P01 CARRIER 38AUD Installation StartUp and Service Instructions.pdf

38AU

Air Cooled Condensing Units 60 Hz With PuronR (R---410A) Refrigerant Sizes 07---14

Installation, Start---Up and Service Instructions

TABLE OF CONTENTS

SAFETY CONSIDERATIONS 2

INSTALLATION GUIDELINES 2

Replacement/Retrofit — R--22 to Puron 2

Rated Indoor Airflow (cfm) 3

Matching 38AU Model to Evaporator Coil 10

INSTALLATION 10 -- 26

Jobsite Survey 10

Step 1 -- Plan for Unit Location 10

Step 2 -- Complete Pre--Installation Checks 10

Step 3 -- Prepare Unit Mounting Support 11

Step 4 -- Rig and Mount the Unit 11

Step 5 -- Determine Refrigerant Line Sizes 11

Step 6 -- Complete Refrigerant Piping Connections 16. . .

Step 7 -- Install Accessories 19

Step 8 -- Complete Electrical Connections 19

Step 9 -- Wind Baffles for Low Ambient Controls 26. . .

PRE-START-UP 26

System Check 26

Turn On Crankcase Heater 26

Preliminary Charge 26

START--UP 26 -- 33

Preliminary Checks 26

Start Unit 27

OPERATING SEQUENCE 34

Base Unit Controls 34

Indoor (Supply) Fan 34

Cooling, Unit Without Economizer 34

38AUDC12, Unit with Hot Gas Bypass (HGBP) 34

Cooling, Unit with Economizer 36

Heating 36

ROUTINE SYSTEM MAINTENANCE 36

Quarterly Inspection (and 30 days after initial start) 36. . .

Seasonal Maintenance 36

SERVICE 36 -- 44

Refrigeration System 36

Compressor Oil 36

Servicing Systems on Roofs with Synthetic Materials 36

Liquid Line Filter Drier 37

Filed Refrigerant Access Ports 37

Factory High--Flow Access Ports 37

Hot Gas Bypass Valve Adjustments 37

Comfort Alert Diagnostic Module 38

Compressor Protection 40

Crankcase Heater 40

Low--Pressure Switch 40

High--Pressure Switch 40

Outdoor Fans 40

Lubrication 40

Routine Cleaning of Round-Tube Plate Fin (RTPF) Coils 43

Fastener Torque Values 44

TROUBLESHOOTING 45 -- 46

APPENDIX A

Air Conditioner & Heat Pump with PuronR — Quick Reference Guide 47

APPENDIX B

Wiring Diagram List 47

APPENDIX C

Low Ambient Option — Factory Installed 48

START--UP CHECKLIST 55 -- 56

SAFETY CONSIDERATIONS

Improper installation, adjustment, alteration, service, maintenance, or use can cause explosion, fire, electrical shock or other conditions which may cause personal injury or property damage. Consult a qualified installer, service agency, or your distributor or branch for information or assistance. The qualified installer or agency must use factory-authorized kits or accessories when modifying this product. Refer to the individual instructions package

Follow all safety codes. Wear safety glasses and work gloves. Use quenching cloths for brazing operations and have a fire extinguisher available. Read these instructions thoroughly and follow all warnings or cautions attached to the unit. Consult local building codes and appropriate national electrical codes (in USA, ANSI/NFPA70, National Electrical Code (NEC); in Canada, CSA C22.1) for special requirements.

It is important to recognize safety information. This is the safety--alert symbol . When you see this symbol on the unit and in instructions or manuals, be alert to the potential for personal injury.

Understand the signal words DANGER, WARNING, CAUTION, and NOTE. These words are used with the safety-alert symbol. DANGER identifies the most serious hazards which will result in severe personal injury or death. WARNING signifies hazards which could result in personal injury or death. CAUTION is used to identify unsafe practices, which may result in minor personal injury or product and property damage. NOTE is used to highlight suggestions which will result in enhanced installation, reliability, or operation.

ELECTRICAL SHOCK HAZARD

Failure to follow this warning could cause in personal injury or death.

Before performing service or maintenance operations on unit, always turn off main power switch to unit and install lockout tag. Unit may have more than one power switch.

! WARNING

UNIT OPERATION AND SAFETY HAZARD

Failure to follow this warning could cause in personal injury,death and/or equipment damage.

PuronR (R--410A) refrigerant systems operate at higher pressures than standard R--22 systems. Do not use R--22 service equipment or components on Puron refrigerant equipment.

! WARNING

PERSONAL INJURY AND ENVIRONMENTAL

HAZARD

Failure to follow this warning could cause in personal injury or death.

Relieve pressure and recover all refrigerant before system repair or final unit disposal.

Wear safety glasses and gloves when handling refrigerants. Keep torches and other ignition sources away from refrigerants and oils.

! WARNING

CUT HAZARD

Failure to follow this caution may result in personal injury.

Sheet metal parts may have sharp edges or burrs. Use care and wear appropriate protective clothing, safety glasses and gloves when handling parts and servicing 38AU units.

CAUTION!

INSTALLATION GUIDELINE

Replacement/Retrofit — R--22 to PuronR

Replacement/retrofit installations require change-out of outdoor unit, metering device, and filter driers.

Change-out of indoor coil (evaporator) and interconnecting tubing is recommended.

Existing evaporator coil – If the existing evaporator coil may be re-used, check with the coil manufacturer to verify the coil construction is suitable for operation with the higher pressures of PuronR (R-410A). Also determine if the existing TXV valve is compatible with R-410A, replace if necessary. The minimum factory test pressure rating must be 250 psig (1725 kPa). Existing coil will need to be purged with Nitrogen to remove as much mineral oil as possible to eliminate cross contamination of oils.

Acid test – If the existing system is being replaced because of a compressor electrical failure, assume acid is in system. If system is being replaced for any other reason, use an approved acid test kit to determine acid level. If even low levels of acid are detected, install a 100 percent activated alumina suction-line filter drier in addition to the replacement liquid-line filter drier.

Remove the suction line filter drier as soon as possible, with a maximum of 72 hr of operation. Recommendation:

Install a ball valve in the liquid line at the filter drier location when installing a suction filter in the suction line.

Existing refrigeration piping – Reuse of existing refrigerant piping involves three issues: quality (strength) of existing tubing, cleanliness and tube size. Inspect all tube segments and joints for signs of damage, corrosion or poor brazing.

Flush the interconnecting piping system with dry Nitrogen to eliminate as much trace of mineral oil as possible.

A U

Same tube sizes are capable of handling higher flowrates (expressed as tons of cooling capacity) with Puron refrigerant compared to R--22 at constant pressure drops.

For example, a 1/2--inch OD liquid line is rated at 33% higher tons with PuronR than with R--22 (at 5_F pressure drop). A 1 1/8--inch OD suction line is rated at 53% higher tons with Puron than with R--22 (at 2_F pressure drop).

Refrigeration lines selected for R--22 use are typically oversized for Puron applications. Carefully check the existing suction line size against the table for maximum size (see Table 8); replace vertical riser segments if necessary.

Check existing liquid line size against sizing data in Table 5 or 6; replace with smaller lines when feasible.

Installation –

1. Remove the existing evaporator coil or fan coil and install the replacement coil when appropriate.

2. Drain oil from low points and traps in suction line tubing (and hot gas bypass tubing if appropriate) and evaporator if they were not replaced. Removing oil from evaporator coil may require purging of the tubing with dry nitrogen.

3. Unless indoor unit is equipped with a Puron approved metering device, change the metering device to a thermal expansion valve (TXV) designed for PuronR (R-410A).

4. Remove the existing outdoor unit. Install the new out-door unit according to these installation instructions.

5. Install a new field-supplied liquid-line filter drier at the indoor coil just upstream of the TXV or fix orifice metering device.

6. If a suction line filter drier is also to be installed, in-stall suction line drier downstream of suction line ser-vice valve at condensing unit.

UNIT DAMAGE HAZARD

Failure to follow this caution may result in equipment damage or improper operation.

Never install suction--line filter drier in the liquid--line of a PuronR system.

CAUTION!

7. If required, install a 100% activated alumina suction line filter drier at the outdoor unit.

8. Evacuate and charge the system according to the in-structions in this installation manual.

9. Operate the system for 10 hr. Monitor the pressure drop across the suction line filter drier. If pressure drop exceeds 3 psig (21kPa), replace suction-line and liquid-line filter driers. Be sure to purge system with dry nitrogen and evacuate when replacing filter driers. Continue to monitor the pressure drop across suction-line filter drier. Repeat filter changes if neces-sary. Never leave suction-line filter drier in system longer than 72 hr (actual time).

Rated Indoor Airflow (cfm)

The table below lists the rated indoor airflow used for the AHRI efficiency rating for the units covered in this document.

38AUZ with 40RUA

Model Numbers Full Load Airflow (cfm)

38AUZ*07 --- 40RUA*07 2400

38AUZ*08 --- 40RUA*08 3000

38AUZ*12 --- 40RUA*12 4000

38AUZ*14 --- 40RUA*14 4375

38AUD with 40RUA

Model Numbers Full Load Airflow (cfm)

38AUD*12 --- 40RUA*12 4000

38AUD*14 --- 40RUA*14 4400

Identify Factory Options —

Factory options will affect 38AU unit pipe sizing selections.

Coil type impacts liquid lift limits; Hot Gas Bypass impacts the selection of suction tube size in vertical riser segments.

Check this unit’s Model Number against the Model Number Nomenclature, Fig. 1. Determine the significance of this unit’s values in Position 9 (Coil type) and Position 6 (Hot Gas Bypass, 38AUDC12 only). Copy the unit’s Model Number from the unit’s dataplate into the open line in the header above Fig. 1 to facilitate this step.

Model Type 38AU= Carrier Condensing Unit Puron® R---410A Refrigerant

Type of Coil

D = Dual Circuit, A/C Scroll Compressor Z = Single Circuit, A/C Scroll Compressor

Refrigerant Options A = None B = Low Ambient C = Hot Gas Bypass (38AUD size 12 only)

Nominal Tonnage 07 = 6 Tons 08 = 7.5 Tons 12 = 10 Tons 14 = 12.5 Tons

Not Used A = Not Used

Not Used 0 = Not Used

3Example 8 A U D C 1 2 A 0 A 6 A 0 A 0 A 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

Packaging 0 = Standard

1 = LTL

Electrical Options A = None C = Non-Fused Disconnect

Service Options 0 = None 1 = Un-powered Convenience Outlet 2 = Powered Convenience Outlet

Not Used A = Place Holder

Design Rev A = Initial Release

Voltage 1 = 575/3/60 5 = 208/ 230/3/60 6 = 460/3/60Coil Options

RTPF

A= Cu/Al B = Precoat (Cu/Al) C = E-Coat (Cu/Al)

M= Cu/Al with Louvered Hail Guard E = Cu/Cu

N = Precoat (Cu/Al) with Louvered Hail Guard P = E-Coat (Cu/Al) with Louvered Hail Guard R = Cu/Cu with Louvered Hail Guard

Base Unit Controls 0 = Electro-Mechanical Controls

Position

Enter this unit’s Model Number

C150027

Fig. 1 -- Model Number Nomenclature

DESIGNATESPOSITION

Week of manufacture (fiscal calander)

Manufacturing location5 Sequence number

Year of manufacture (”12” = 2012) 1−2

6−10

3−4

POSITION NUMBER

TYPICAL

1 2 3 4 5 6 7 8 9 10 0 5 1 2 C 1 2 3 4 5

C12439

Fig. 2 -- Serial Number Nomenclature

C11092

UNIT

STD. UNIT WT. CORNER A CORNER B CORNER C CORNER D CENTER OF GRAVITY UNIT HEIGHT

lbs. kg. lbs. kg. lbs. kg. lbs. kg. lbs. kg. X Y Z H

38AUZ*07

(RTPF) 389 176 141 64 96 44 62 28 91 41 18

[457.2]

[609.6]

[533.4] 42 3/8 [1076.0]

38AUZ*08

(RTPF) 391 177 142 64 96 44 62 28 91 41 18

[457.2]

[609.6]

[533.4] 42 3/8 [1076.0]

38AUZ*12

(RTPF) 490 222 177 80 120 54 78 35 114 52 18

[457.2]

[609.6]

[609.6] 50 3/8 [1279.2]

38AUZ*14

(RTPF) 598 271 195 88 142 64 110 50 151 68 20

[508.0]

[635.0]

[609.6] 50 3/8 [1279.2]

38AUD*12

(RTPF) 516 234 185 84 117 53 83 38 131 59 19

[482.6]

[584.2]

[609.6] 50 3/8 [1279.2]

38AUD*14

(RTPF) 654 297 214 97 155 70 120 54 165 75 20

[508.0]

[635.0]

[609.6] 50 3/8 [1279.2]

LEGEND: RTPF = Round Tube/Plate Fin coil

Fig. 3 -- 38AU Unit Dimensions

Table 1A — Physical Data — 38AUZ*07-14 Units — 60 Hz English

UNIT SIZE 38AU Z*07 Z*08 Z*12 Z*14

NOMINAL CAPACITY (tons) 6 7.5 10 12.5

OPERATING WEIGHTS (lb)

Round Tube/Plate Fin Coil (Cu/Al) 389 391 490 598

REFRIGERANT TYPE‡ R-410A

RTPF Operating Charge, Typical (lb)† 14.0 17.0 20.0 46.0

RTPF Shipping Charge (lb) 11.0 13.0 16.0 35.0

COMPRESSOR

Qty...Type 1...Scroll 1...Scroll 1...Scroll 1...Scroll

Oil Charge (oz) 56 60 110 110

CONDENSER FANS

Qty...Rpm 2...1100

Motor Hp 1/4

Diameter 22

Nominal Airflow (Cfm Total) 6000

Watts (Total) 610

RTPF CONDENSER COIL

Material (Tube/Fin) Cu / Al

Coil Type 3/8--- in RTPF

Rows/Fins per inch (FPI) 2 / 17 3 / 17

Face Area (sq ft total) 17.5 17.5 25.1 31.8

CONTROLS

Pressurestat Settings (psig)

High Cutout 630 10

Cut-in 505 20

Low Cutout 54 3

Cut-in 117 5

PIPING CONNECTIONS (in. ODS)

Qty...Suction 1...1 1/8 1...1 1/8 1...1 3/8 1...1 3/8

Qty...Liquid 1...3/8 1...1/2 1...1/2 1...5/8

LEGEND

RTPF — Round Tube/Plate Fin ODS — Outside Diameter Sweat (socket)

‡ Unit is factory-supplied with partial charge only.

† Typical operating charge with 25 ft of interconnecting piping.

Table 1B — Physical Data — 38AUZ*07-14 Units — 60 Hz SI

UNIT SIZE 38AU Z*07 Z*08 Z*12 Z*14

NOMINAL CAPACITY (kW) 21.1 26.4 35.1 44

OPERATING WEIGHTS (lb)

Round Tube/Plate Fin Coil (Cu/Al) 176 177 222 271

REFRIGERANT TYPE‡ R-410A

RTPF Operating Charge, Typical (kg)† 6.4 7.7 9.1 20.9

RTPF Shipping Charge (kg) 5.0 5.9 7.3 15.9

COMPRESSOR

Qty...Type 1...Scroll 1...Scroll 1...Scroll 1...Scroll

Oil Charge (oz) 1.7 1.8 3.3 3.3

CONDENSER FANS

Qty...r/s 2...18

Motor Hp NEMA 1/4

Diameter (mm) 560

Nominal Airflow (L/s) 2832

Watts (Total) 610

RTPF CONDENSER COIL

Material (Tube/Fin) Cu / Al

Coil Type 3/8--- in RTPF

Rows/Fins per Meter (Fins/m) 2 / 670 3 / 670

Face Area (sq m total) 1.6 1.6 2.3 3.0

CONTROLS

Pressurestat Settings (kPa)

High Cutout 4347 70

Cut-in 3482 138

Low Cutout 372 21

Cut-in 807 34

PIPING CONNECTIONS (in. ODS)

Qty...Suction 1...1 1/8 1...1 1/8 1...1 3/8 1...1 3/8

Qty...Liquid 1...3/8 1...1/2 1...1/2 1...5/8

LEGEND

RTPF — Round Tube/Plate Fin NEMA — National Electrical Manufacturers Association ODS — Outside Diameter Sweat (socket)

‡ Unit is factory-supplied with partial charge only.

† Typical operating charge with 25 ft of interconnecting piping.

Table 2A — Physical Data — 38AUD*12-14 Units — 60 Hz English

UNIT SIZE 38AU D*12 D*14

NOMINAL CAPACITY (tons) 10 12.5

OPERATING WEIGHTS (lb)

Round Tube/Plate Fin Coil (Cu/Al) 516 654

REFRIGERANT TYPE‡ R-410A

RTPF Operating Charge 1/2, Typical (lb)† 11.0 / 11.0 23.0/23.0

RTPF Shipping Charge 1/2 (lb) 8.0 / 8.0 17.0/17.0

COMPRESSOR

Qty...Type 2...Scroll 2...Scroll

Oil Charge 1/2 (oz) 42 60

CONDENSER FANS

Qty...Rpm 2...1100

Motor Hp 1/4

Diameter 22

Nominal Airflow (Cfm Total) 6000

Watts (Total) 610

RTPF CONDENSER COIL

Material (Tube/Fin) Cu / Al

Coil Type 3/8--- in RTPF

Rows/Fins per inch (FPI) 2 / 17 3 / 17

Face Area (sq ft total) 25.1 31.8

CONTROLS

Pressurestat Settings (psig)

High Cutout 630 10

Cut-in 505 20

Low Cutout 54 3

Cut-in 117 5

PIPING CONNECTIONS (in. ODS)

Qty...Suction 1/2 1...1 1/8 / 1...1 1/8 1...1 3/8 / 1...1 3/8

Qty...Liquid 1/2 1...3/8 / 1...3/8 1...1/2 / 1...1/2

LEGEND

RTPF — Round Tube/Plate Fin ODS — Outside Diameter Sweat (socket)

‡ Unit is factory-supplied with partial charge only.

† Typical operating charge with 25 ft of interconnecting piping.

Table 2B — Physical Data — 38AUD*12-14 Units — 60 Hz SI

UNIT SIZE 38AU D*12 D*14

NOMINAL CAPACITY (kW) 35.1 44

OPERATING WEIGHTS (kg)

Round Tube/Plate Fin Coil (Cu/Al) 234 297

REFRIGERANT TYPE‡ R-410A

RTPF Operating Operating 1/2 (kg) 5.0 / 5.0 10.4 / 10.4

RTPF Shipping Charge 1/2 (kg) 3.6 / 3.6 7.7 / 7.7

COMPRESSOR

Qty...Type 2...Scroll 2...Scroll

Oil Charge 1/2 (L) 1.2 1.7

CONDENSER FANS

Qty...r/s 2...1100

Motor Hp NEMA 1/4

Diameter (mm) 560

Nominal Airflow (Cfm Total) 6000

Watts (Total) 610

RTPF CONDENSER COIL

Material (Tube/Fin) Cu / Al

Coil Type 3/8--- in RTPF

Rows/Fins per Meter (Fins/m) 2 / 670 3 / 670

Face Area (sq m total) 2.3 3.0

CONTROLS

Pressurestat Settings (kPa)

High Cutout 4347 70

Cut-in 3482 138

Low Cutout 372 21

Cut-in 807 34

PIPING CONNECTIONS (in. ODS)

Qty...Suction 1/2 1...1 1/8 / 1...1 1/8 1...1 3/8 / 1...1 3/8

Qty...Liquid 1/2 1...3/8 / 1...3/8 1...1/2 / 1...1/2

LEGEND

RTPF — Round Tube/Plate Fin NEMA — National Electrical Manufacturers Association ODS — Outside Diameter Sweat (socket)

‡ Unit is factory-supplied with partial charge only.

† Typical operating charge with 7.62 m of interconnecting piping.

Matching 38AU Model to Evaporator Coil

The Model 38AUZ is a single-circuit unit design, requiring one set of refrigeration piping. This model can be connected to an evaporator coil with one circuit or with two circuits (by manifolding the evaporator connections into a single piping system).

The Model 38AUD is a dual-circuit unit design that requires two sets of refrigeration piping between the outdoor unit and the evaporator coil (or coils). This model can only be connected to an evaporator coil that has two refrigeration circuits (or to two separate evaporator coils).

The Model 38AUD CANNOT be connected to a single-circuit evaporator coil. The Model 38AUD CANNOT be field-converted to a single-circuit design.

Table 3 – Evaporator Coil Connections

Evaporator Coil has Connect to Model Notes

Single Circuit 38AUZ ONLY

Two Circuits 38AUZ Manifold evaporator circuits into single piping system

Or

38AUD Use two separate piping systems

Before unpacking this new 38AU model, compare the evaporator coil design to the 38AU model.

.INSTALLATION

Jobsite Survey

Complete the following checks before installation.

1. Consult local building codes and the NEC (National Electrical Code) ANSI/NFPA 70 for special installa-tion requirements.

2. Determine unit location (from project plans) or select unit location.

3. Check for possible overhead obstructions which may interfere with unit lifting or rigging.

Step 1 — Plan for Unit Location

The 38AU units are designed and approved for outdoor installation only. Do not locate these units indoors. Do not add ducting to unit fan system.

Select a location for the unit and its support system (pad, rails or other) that provides for the minimum clearances required for safety. This includes the clearance to combustible surfaces, unit performance and service access below, around and above unit as specified in unit drawings.

See Fig. 4.

NOTE: Local codes may require different clearances than specified in Fig. 4. It is the responsibility of installers to be knowledgeable in local codes and to modify the recommended clearances to satisfy local codes.

NOTE: Consider also the effect of adjacent units on airflow performance and control box safety clearance.

REAR:

Min 18” (457 mm) requried for service

Note: Observe requirements for 39” (914 mm) operating clearance on either Left or Rear coil opening.

RIGHT:

Min 18” (457 mm) requried for service

LEFT:

Min 18” (457 mm) requried for service

FRONT:

42” (1067 mm) requried for service

C110201

Fig. 4 -- Service Clearance Dimensional Drawing

Do not install the outdoor unit in an area where fresh air supply to the outdoor coil may be restricted or when recirculation from the condenser fan discharge is possible.

Do not locate the unit in a well or next to high walls.

Evaluate the path and required line length for interconnecting refrigeration piping, including suction riser requirements (outdoor unit above indoor unit), liquid line lift (outdoor unit below indoor unit) and hot gas bypass line. Relocate sections to minimize the length of interconnecting tubing.

DO NOT BURY REFRIGERATION LINES.

Although unit is weatherproof, avoid locations that permit water from higher level runoff and overhangs to fall onto the unit.

Step 2 — Complete Pre-Installation Checks

Check Unit Electrical Characteristics: Confirm before installation of unit that voltage, amperage and circuit protection requirements listed on unit data plate agree with power supply provided.

Un--crate Unit: Remove unit packaging except for the top skid assembly, which should be left in place until after the unit is rigged into its final location.

Inspect Shipment: File a claim with shipping company if the shipment is damaged or incomplete.

Consider System Requirements:

S Consult local building codes and National Electrical Code (NEC, U.S.A.) for special installation requirements.

S Allow sufficient space for airflow clearance, wiring, refrigerant piping, and servicing unit. See Fig. 3 for unit dimensions and weight distribution data.

S Locate the unit so that the outdoor coil (condenser) airflow is unrestricted on all sides and above.

S The unit may be mounted on a level pad directly on the base channels or mounted on raised pads at support points. See Tables 1A through 2B for unit operating weights. See Fig. 3 for weight distribution based on recommended support points.

NOTE: If vibration isolators are required for a particular installation, use the data in Fig. 3 to make the proper selection.

Step 3 — Prepare Unit Mounting Support

Slab Mount —

Provide a level concrete slab that extends a minimum of 6

in. (150 mm) beyond unit cabinet. Install a gravel apron in front of condenser coil air inlet to prevent grass and foliage from obstructing airflow.

Step 4 — Rig and Mount the Unit

UNIT DAMAGE HAZARD

Failure to follow this caution may result in equipment damage.

All panels must be in place when rigging. Unit is not designed for handling by fork truck.

CAUTION!

Rigging: These units are designed for overhead rigging.

Refer to the rigging label for preferred rigging method.

Spreader bars are not required if top crating is left on the unit. All panels must be in place when rigging. As further protection for coil faces, plywood sheets may be placed against the sides of the unit, behind cables. Run cables to a central suspension point so that the angle from the horizontal is not less than 45 degrees. Raise and set the unit down carefully.

If it is necessary to roll the unit into position, mount the unit on longitudinal rails, using a minimum of 3 rollers.

Apply force to the rails, not the unit. If the unit is to be skidded into position, place it on a large pad and drag it by the pad. Do not apply any force to the unit.

Raise from above to lift the unit from the rails or pad when unit is in its final position.

After the unit is in position, remove all shipping materials and top crating.

Step 5 — Determine Refrigerant Line Sizes

Select the recommended line sizes for 38AUZ and 38AUD unit from the appropriate tables.

Determine the linear length of interconnecting piping required between the outdoor unit and indoor unit (evaporator). Consider and identify also the arrangement of the tubing path (quantity and type of elbows in both lines), liquid line solenoid size, filter drier and any other refrigeration specialties located in the liquid line. Refer to the indoor unit installation instructions for additional details on refrigeration specialties devices.

Determine equivalent line length adjustments for path and components and add to linear line lengths. See Table 4, Equivalent Lengths for Common Fittings, for usual fitting types. Also identify adjustments for refrigeration specialties. Refer to Part 3 of the Carrier System Design Manual for additional data and information on equivalent lengths.

Table 4 – Equivalent Lengths for Common Fittings (ft)

Nominal Tube OD

Elbows

90 Std 90 Lrad 90 Street 45 Std 45 Street 3/8 1.3 0.8 2.2 0.6 1 1/2 1.4 0.9 2.3 0.7 1.1 5/8 1.6 1 2.5 0.8 1.3 3/4 1.8 1.2 2.9 0.9 1.5 7/8 2 1.4 3.2 0.9 1.6

1 1/8 2.6 1.7 4.1 1.3 2.1

1 3/8 3.3 2.3 5.6 1.7 3

1 5/8 4 2.6 6.3 2.1 3.4

2 1/8 5 3.3 8.2 2.6 4.5

Nominal Tube OD

Tees

Branch Flow

Straight-Thru

No Reduct Reduce 25% Reduce 50% 3/8 2.6 0.8 1.1 1.3 1/2 2.7 0.9 1.2 1.4 5/8 3 1 1.4 1.6 3/4 3.5 1.2 1.7 1.8 7/8 4 1.4 1.9 2

1 1/8 5 1.7 2.3 2.6

1 3/8 7 2.3 3.1 3.3

1 5/8 8 2.6 3.7 4

2 1/8 10 3.3 4.7 5

NOTE: Equivalent line lengths will vary based on tube diameter. Calculate equivalent line length for each pipe by adding equivalent length adjustments to linear lengths for each pipe.

Enter the appropriate table to select the recommended line sizes.

Model/ Position #6 Table Quantity of Line Sets

38AUZ / all 5 1

38AUD / A,B 6 2

38AUD / C 7 2

Liquid Lift —

A liquid lift condition exists when the outdoor unit is located below the indoor (evaporator) unit and liquid flows vertically up in a portion of the liquid line. The vertical column of liquid reduces the available state point subcooling at the evaporator coil’s thermal expansion valve. This effect reduces the length of liquid lift (feet of elevation) that a liquid line size can accommodate. Longer linear tube lengths will also reduce the amount of liquid lift possible.

Check Tables 5 (38AUZ), 6 (38AUD) and 7 (38AUDC12) for maximum liquid lift capabilities for line sizes. Reselect the liquid line tube size if necessary. If maximum available tube size cannot provide the required lift distance on this installation, relocate the outdoor unit to reduce the equivalent line length or the lift requirement.

Table 5 – 38AUZA/B 07-14 Piping Recommendations (Single-Circuit Unit) R---410A Linear Length Ft 0---25 25---50 50---75 75---100 100---125 m 0---8 8---15 15---23 23---30 30---38

Equivalent Length

Ft 0---38 38---75 75---113 113---150 150---188 m 0---12 12---23 23---34 34---46 46---57

Model 38AUZA/B07 Liquid Line 3/8 3/8 or 1/2 1/2 1/2 or 5/8 1/2 or 5/8

Max Lift (ft) RTPF 25 50 or 50 75 100 or 100 125 or 125 Suction Line 7/8 or 1-1/8 7/8 or 1-1/8 1-1/8 1-1/8 1-1/8 Suction PD (_F) 1.0 or 0.3 2.1 or 0.6 0.9 1.2 1.5 Charge (lbs) RTPF 14.0 15.2 or 16.7 18.6 20.6 or 24.4 22.5 or 28.2

38AUZA/B08 Liquid Line 1/2 1/2 1/2 1/2 1/2 Max Lift (ft)

RTPF 25 50 75 100 93

Suction Line 7/8 or 1-1/8 1-1/8 1-1/8 1-1/8 1-1/8 Suction PD (_F) 1.8 or 0.5 1.0 1.4 1.9 2.4 Charge (lbs)

RTPF 18.6 19.7 21.7 23.8 25.5

38AUZA/B12 Liquid Line 1/2 1/2 1/2 or 5/8 1/2 or 5/8 1/2 or 5/8 Max Lift (ft) RTPF 25 50 57 or 75 61 or 100 47 or 99 Suction Line 1-1/8 1-1/8 1-1/8 1-1/8 or 1-3/8 1-1/8 or 1-3/8 Suction PD (_F) (Cap Red)

0.7 1.4 2.1 2.8 or 1.0 (-1.4%)

3.5 or 1.2 (-2.6%)

Charge (lbs) RTPF 19.8 21.8 23.5 or 26.2 26.2 or 29.9 DNU or 33.0

38AUZA/B14 Liquid Line 1/2 1/2 or 5/8 1/2 or 5/8 1/2 or 3/4 1/2 or 3/4 Max Lift (ft) RTPF 25 50 or NR 75 or NR 100 or NR 125 or NR Suction Line 1-1/8 1-1/8 1-3/8 1-3/8 1-3/8 Suction PD (_F) 1.2 2.4 1.3 1.7 2.2 Charge (lbs) RTPF 46.0 47.9 or NR 50.4 or NR 56.3 or NR 59.3 or NR

Legend:

Linear Length Linear tubing length, feet

Equivalent Length Equivalent tubing length, including effects of refrigeration specialties devices

Liquid Line Tubing size, inches OD.

Max Lift Maximum liquid lift (indoor unit ABOVE outdoor unit only), at maximum permitted liquid line pressure drop S Linear Length Less than 75 ft (23 m): Minimum 2.0° F subcooling entering TXV S Linear Length Greater than 75 ft (23m): Minimum 0.5° F subcooling entering TXV

Suction Line Tube size, inches OD

Suction PD (_F) Suction Line Pressure Drop, saturated temperature, _F

(Cap Red) Capacity Reduction caused by suction line PD greater than 2_F

Charge Charge Quantity, lbs. Calculated for both liquid line sizes (where applicable), but only with larger suction line size (where applicable)

DNU Do Not Use (pressure drop exceeds available subcooling in this model)

NR Not Recommended (use smaller liquid tube size)

NOTE: For applications with equivalent length greater than 188 ft (57 m) and/or linear length greater than 125 ft (38 m), contact your local Carrier representative.

Table 6 – 38AUDA/B 12-14 Piping Recommendations (Two-Circuit Unit)

NOTE: 38AUDA/B requires TWO sets of refrigeration piping R---410A Linear Length Ft 0---25 25---50 50---75 75---100 100---125 m 0---8 8---15 15---23 23---30 30---38 Equivalent Length

Ft 0---38 38---75 75---113 113---150 150---188 m 0---12 12---23 23---34 34---46 46---57

Model 38AUDA/B12 Liquid Line 3/8 3/8 3/8 or 1/2 3/8 or 1/2 3/8 or 1/2

Max Lift (ft) RTPF 25 50 75 or NR 83 or 100 62 or 125 Suction Line 7/8 7/8 1-1/8 1-1/8 1-1/8 Suction PD (_F) 1.1 2.1 0.9 1.2 1.5 Charge (lbs) (ea circuit) RTPF 13.3 14.3 15.8 or NR 16.9 or 20.0 18.1 or 22.0

38AUDA/B14 Liquid Line 3/8 3/8 3/8 or 1/2 3/8 or 1/2 3/8 or 1/2 Max Lift (ft) RTPF 25 50 75 or NR 54 or 100 45 or 125 Suction Line 7/8 7/8 1-1/8 1-1/8 1-/8 Suction PD (_F) 1.1 2.2 1.0 1.3 1.6 Charge (lbs) (ea circuit) RTPF 23.0 24.0 27.8 or NR 26.6 or 29.7 27.8 or 31.7

Legend:

Linear Length Linear tubing length, feet

Equivalent Length Equivalent tubing length, including effects of refrigeration specialties devices

Liquid Line Tubing size, inches OD.

Max Lift Maximum liquid lift (indoor unit ABOVE outdoor unit only), at maximum permitted liquid line pressure drop S Linear Length Less than 75 ft (23 m): Minimum 2.0° F subcooling entering TXV S Linear Length Greater than 75 ft (23m): Minimum 0.5° F subcooling entering TXV

Suction Line Tube size, inches OD

Suction PD (_F) Suction Line Pressure Drop, saturated temperature, _F

(Cap Red) Capacity Reduction caused by suction line PD greater than 2_F

Charge Charge Quantity, lbs. Calculated for both liquid line sizes (where applicable), but only with larger suction line size (where applicable)

DNU Do Not Use (pressure drop exceeds available subcooling in this model)

NR Not Recommended (use smaller liquid tube size)

NOTE: For applications with equivalent length greater than 188 ft (57 m) and/or linear length greater than 125 ft (38 m), contact your local Carrier representative.

Table 7 – 38AUDC12 HGBP Piping Recommendations (Two-Circuit Unit)

NOTE: 38AUDC units require TWO sets of refrigeration piping

R-410A

Linear Length Ft 0-25 25-50 50-75 75-100 100-125 m 0-8 8-15 15-23 23-30 30-38

Equivalent Length

Ft 0-38 38-75 75-113 113-150 150-188 m 0-12 12-23 23-34 34-46 46-57

Model

38AUDC12 Liquid Line 3/8 3/8 3/8 3/8 1/2 3/8 1/2 Pressure Drop 1.8 3.5 5.2 8.7 1.2 8.7 1.5

Max Lift 25 50 75 65 100 62 125

Pressure Drop 3.8 7.5 11.3 12.2 9.4 13.7 11.7

Suction Line

Circuit 1: VAPOR RISER REQUIRED, NOT GREATER THAN 20 FT (6.1 M) --- See Fig. 5)

Tube S 5/8 1-1/8 1-3/8 1-3/8 1-3/8 Tube A 5/8 5/8 5/8 5/8 5/8 Pressure Drop 2.0 2.0 1.9 2.0 2.0

Circuit 1: VAPOR RISER GREATER THAN 20 FT (6.1 M) --- See Fig. 6)

Tube S 5/8 7/8 7/8 1-1/8 1-1/8 Tube A 5/8 5/8 5/8 5/8 5/8 Tube B NR 1/2 5/8 5/8 5/8 Pressure Drop 2.0 1.6 1.7 1.7 2.1

Circuit 1: NO VAPOR RISER REQUIRED 7/8 7/8 1-1/8 1-1/8 1-1/8

Circuit 2: 7/8 7/8 1-1/8 1-1/8 1-1/8 Pressure Drop 1.1 2.1 0.9 1.2 1.5

Charge (lbs) 1/2 13.3 14.3 15.8 16.9 20.0 18.1 22.0

Legend:

Equivalent Length Equivalent tubing length, including effects of refrigeration specialties devices

Linear Length Typical linear tubing length (50% added to linear to define Equivalent Length for this table)

Liquid Line Tubing size, inches OD.

Max Lift Maximum liquid lift (indoor unit ABOVE outdoor unit only), at maximum permitted liquid line pressure drop — S Linear Length Less than 75 ft (23 m): Minimum 2.0° F subcooling entering TXV S Linear Length Greater than 75 ft (23m): Minimum 0.5° F subcooling entering TXV

Suction Line Tube size, inches OD

Charge Charge Quantity, lbs. Calculated for both liquid line sizes (where applicable), but only with larger suction line size (where applicable)

NOTE: For applications with equivalent length greater than 188 ft (57 m) and/or linear length greater than 125 ft (38 m), contact your local Carrier representative.

Suction Riser —

A suction riser condition exists when the outdoor unit is located above the indoor (evaporator) unit and suction vapor must flow vertically up to return to the compressor.

Oil return is a concern when the suction tube size is too large to produce the minimum refrigerant velocity to ensure oil return at minimum load conditions.

38AUZ (All) and 38AUD (A,B) WITHOUT HGBP Check Table 8 for maximum suction tube size for 38AU units at minimum load conditions. Consider suction speed riser (reduced tube size for vertical segment only) or double suction riser arrangement if the planned suction tube size does not provide necessary minimum flowrates for this riser.

Table 8 – 38AU Maximum Suction Pipe Size

Model: Unit Size Maximum Tube Size

38AUZA,B 07 1 3/8

08 1 5/8

12 1 5/8

14 2 1/8

38AUDA,B 12 1 3/8

14 1 5/8

38AUDC 12 See Table 7

38AUDC12 WITH OPTIONAL HOT GAS BYPASS

Special consideration for suction riser requirements must be considered when applying this factory--installed hot gas bypass. It is extremely important to consider the lowest possible refrigerant tons of refrigerant flow when hot gas bypass is functioning to assure proper oil return up suction risers.

Table 7 provides recommended tube sizes for model 38AUDC12 unit which includes the factory--installed hot gas bypass system on Circuit 1. The selections in this table are based on evaluations of system minimum load operating conditions for comfort cooling applications, with compressor saturated suction pressure to 28_F (--2.2_C) minimum.

Table 7 includes liquid line size selections based on use of RTPF coil option only.

Table 7 includes three different suction line size selections for Circuit 1 based on the elevation difference conditions between the 38AUD unit and the evaporator coil location.

Outdoor unit ABOVE evaporator coil: This installation will have at least one suction riser segment. If the vertical elevation difference is less than 20--ft (6.1 m) linear feet and requires only one or two segments, consider a speed riser selection for Circuit 1; use the line marked VAPOR

RISER REQUIRED; NOT GREATER THAN 20 FT

(6.1 M). See Fig. 5. Tube S is the horizontal line size;

tube A is the reduced diameter riser size.

CONDENSING

UNIT

20-FT (6.1 M) MAX

A

A - Suction Riser Without Trap

LEGEND

S - Suction Line to Condensing Unit

S

C12404

Fig. 5 -- Suction Line Piping -- Speed Riser

If the vertical elevation difference is greater than 20--ft (6.1--m) linear feet or requires more than two short lift segments, select the Circuit 1 suction line size from Double Suction Riser lines data under VAPOR RISER GREATER THAN 20 FT (6.1 M). See Fig. 6. Tube S is the horizontal line size. Tube A is the reduced diameter riser size without bottom trap; Tube B is the parallel riser size with bottom oil trap.

FROM

EVAPORATOR

A

A - Suction Riser Without Trap

B - Suction Riser With Trap

S - Suction Line to Condensing Unit

LEGEND

B

S

S

C12405

Fig. 6 -- Suction Line Piping -- Double Riser

Outdoor unit BELOW evaporator coil and no vertical riser segments: Select Circuit 1 suction line size from NO VAPOR RISER line.

Circuit 2 suction line: Because there is no hot gas bypass system in Circuit 2, no special riser selections are necessary. Select Circuit 2 suction line from bottom line for all 38AUDC installations.

Vertical Separation (outdoor unit above indoor unit) –

Vertical elevation difference of 200 ft (60 m) is permitted when the outdoor unit (38AUZ or 38AUD) is located above the indoor unit.

Step 6 — Complete Refrigerant Piping Connections

IMPORTANT: Do not bury refrigerant piping underground.

IMPORTANT: A refrigerant receiver is not provided with the unit. Do not install a receiver.

Provide Safety Relief —

If local codes dictate an additional safety relief device, purchase locally and install locally. Installation will require the recovery of the factory shipping charge before the factory tubing can be cut and the supplemental relief device is installed.

Model 38AUD has two separate refrigeration systems. If required, each circuit will require a field-supplied/installed supplemental relief device.

Check 38AU Model with Evaporator Coil Connections —

Confirm before installation of unit that the evaporator coil connections are consistent with this 38AU model. See Table 3 on page 10.

Insulate Suction Lines —

Apply closed-cell tubular insulation to all suction lines between evaporator coil connection and 38AU unit’s suction service valve.

38AUD Piping Connections —

The 38AUD’s two circuits are designated Circuit 1 and Circuit 2. Circuit 1 is controlled by the thermostat’s Y1 (or TC1) contact and will be the first circuit on and last circuit off. Circuit 2 is controlled by the thermostat’s Y2 (or TC2) contact and this circuit is always the “lag” circuit.

See Fig. 7 for location of Circuit 1 and Circuit 2 service valves and field piping connections. Circuit 1 is on the right-hand side of the service valve compartment; Circuit 2 is on the left.

When a single piece evaporator coil with two separate circuits is connected to a 38AUD, the lower coil circuit should be connected to the 38AUD’s Circuit 1 so that the evaporator’s lower coil segment is first-on/last-off (to avoid re-evaporation of condensate on dry lower coil segments).

Circuit 1 Connections

Circuit 2 Connections

CKT

2 CKT

C10912 Fig. 7 -- 38AUD Service Valve Locations

Plan the Circuit 1 and Circuit 2 tubing segments carefully, mark each segment and check constantly as piping systems are assembled to avoid piping errors.

38AUD unit cannot be field-piped as a single-circuit/tandem system.

Final Tubing Check. 38AUD —

Before completing the field piping connections to the 38AUD unit service valves, confirm that the suction line to the indoor coil’s first--on/last--off circuit (and its companion liquid line) are correctly identified as Circuit 1 use for the 38AUD unit. If a suction riser is required, it must be in Circuit 1.

Connecting 40RU to 38AUD: The 40RU fan coil in sizes 12, 14 and 16 is a face-split coil design that also has its circuits designated as 1 and 2. See Fig. 8. Note that the lower coil segment changes as the arrangement of the 40RU changes. In a vertical arrangement, the 40RU’s lower coil segment is segment 2; this segment should be connected to the 38AUD’s Circuit 1. In a horizontal arrangement, the 40RU’s lower segment is now segment 1; this segment should be connected to the 38AUD’s Circuit 1.

Note that refrigerant suction piping should be insulated.

40RU

Arrangement

Cooling Stage

40RU Coil Segment

Connect to

38AUD

Vertical Y1 Y2

Circuit 1 Circuit 2

Horizontal Y1 Y2

Circuit 1 Circuit 2

FIRST ON/LAST OFF = 2

VERTICAL INSTALLATION

FIRST ON/LAST OFF = 1

HORIZONTAL INSTALLATION

C10071

Fig. 8 -- Typical Evaporator Coil Connections (40RU)

Install Filter Drier(s) and Moisture Indicator(s) —

Every unit MUST have a filter drier in the liquid line.

38AUD models require two filter driers (one in each liquid line). Locate the filter drier(s) at the indoor unit, close to the evaporator coil’s thermal expansion valve (TXV) inlets.

38AU units include one (38AUZ) or two (38AUD) Puron-duty filter drier(s), shipped in cartons attached to the unit basepan. Remove the filter drier(s) and prepare to install in the liquid line(s) at the evaporator coil. Do not remove connection fitting plugs until ready to connect and braze the filter drier into the liquid line position.

Table 9 – Puron-duty Filter Drier(s)

Model-Size Qty Liquid Line OD

Desiccant Volume

Part Number Ref

38AUZ*07 1 3/8-in 8 cu. in. KH43LG091 38AUZ*08 1 1/2-in 16 cu. in. KH43LG085 38AUZ*12 1 1/2-in 16 cu. in. KH43LG085 38AUZ*14 1 5/8-in 16 cu. in. KH43LG086 38AUD*12 2 3/8-in 8 cu. in. KH43LG091 38AUD*14 2 1/2-in 16 cu. in. KH43LG085

Installation of liquid line moisture indicating sightglass in each circuit is recommended. Locate the sightglass(es) between the outlet of the filter drier and the TXV inlet.

Refer to Table 10 for recommendations on refrigeration specialties.

In some applications, depending on space and convenience requirements, it may be desirable to install 2 filter driers and sight glasses in a single circuit application. One filter drier and sight glass may be installed at A locations (see Fig. 9) or 2 filter driers and sight glasses may be installed at B locations (see Figs. 9 and 10).

Select the filter drier for maximum unit capacity and minimum pressure drop. Complete the refrigerant piping from the indoor unit to the outdoor unit before opening the liquid and suction lines at the outdoor unit.

Install Liquid Line Solenoid Valve —

It is recommended that a solenoid valve be placed in the main liquid line (see Figs. 9 and 10) between the condensing unit and the evaporator coil. Locate the solenoid valve at the outlet end of the liquid line, near the evaporator coil connections, with flow direction arrow pointed at the evaporator coil. Refer to Table 10. (A liquid line solenoid valve is required when the liquid line length exceeds 75 ft [23 m].) This valve prevents refrigerant migration (which causes oil dilution) to the compressor during the off cycle, at low outdoor ambient temperatures. Wire the solenoid in parallel with the compressor contactor coil (see Figs. 9 and 10). This means of electrical control is referred to as solenoid drop control.

INDOOR

COIL CKT 2

AIRFLOW

INDOOR

COIL CKT 1

AIRFLOW

15 DIAMS

MIN 10

DIAMS

8 DIAMS

MIN

TXV

SENSING

BULB

EQUALIZER LINE

SIGHT GLASS

A LOCATION

SIGHT

GLASSES

B LOCATION

TXV

CKT 2

FILTER DRIER

A LOCATION

FILTER

DRIERS

B LOCATION

FLOWTXV

SENSING

BULB

TXV

CKT 1

8 DIAMS

MIN

15 DIAMS

MIN 10

DIAMS

Single Circuit Coil Piping Configuration For single compressor condensing units

Dual Circuit Coil Piping Configuration For single compressor condensing units

15 DIAMS

MIN 10

DIAMS

8 DIAMS

MIN

INDOOR

COIL CKT

AIRFLOW

TXV

SENSING

BULB

EQUALIZER LINE

SIGHT GLASS

A LOCATION

TXV

FILTER DRIER

A LOCATION

LIQUID LINE

SOLENOID

VALVE

FLOW

LIQUID LINE

SOLENOID

VALVE

C10202

Fig. 9 -- Location of Sight Glass(es) and Filter Driers Typical 38AUZ Systems

AIRFLOW

SUCTION

CIRCUIT 2

SUCTION

CIRCUIT 1

AIRFLOW

15 DIAMS

MIN 10

DIAMS

8 DIAMS

MIN

TXV

SENSING

BULB

EQUALIZER LINE

SIGHT

GLASSES

TXV

CKT 2

FILTER

DRIERS

LIQUID LINE

SOLENOID VALVE

CIRCUIT 2

FLOW

LIQUID LINE

SOLENOID VALVE

CIRCUIT 1

FLOW

TXV

SENSING

BULB

TXV

CKT 1

8 DIAMS

MIN

15 DIAMS

MIN 10

DIAMS

Dual Circuit Coil Piping Configuration For two circuit condensing units

C10072

Fig. 10 -- Location of Sight Glasses and Filter Driers Typical 38AUD Systems

Table 10 – Refrigerant Specialties Part Numbers

LIQUID LINE

SIZE (in.)

LIQUID LINE

SOLENOID VALVE (LLSV)

LLSV

COIL

SIGHT

GLASS

FILTER

DRIER

3/8 EF680033 EF680037 KM680008

provided with unit see Table 9

1/2 EF680035 EF680037 KM680004

5/8 EF680028 EF680032 KM680005

38AUD units require TWO sets of parts.

Solenoid drop control wiring: Control the power to the liquid line solenoid through a Solenoid Valve Relay (SVR) in all units. Use part number HN61PC005 (field--supplied, installed). 38AUZ unit requires one SVR; 38AUD unit requires two relays.

A unit with two liquid line solenoid valves also requires a separate control power transformer for the liquid solenoid valve loads. Select TRAN3 transformer part number according to unit power supply.

Model Qty

LSV

Relay SVR Qty---Part Nbr

TRAN3

Primary V:Part Nbr

38AUZ 1 1 --- HN61PC005 N/R

2 2 --- HN61PC005 208/230V:HT01BD202

460V: HT01BD702

575V: HT01BD90238AUDA,B 2 2 --- HN61PC005

38AUDC 2 1 --- HN61PC005* N/R #

LSV: Liquid Solenoid Valve SVR: Solenoid Valve Relay N/R: Not Required N/R #: Not Required / Factory Installed *: Install as SVR---2 (SVR---1 is factory---installed)

Mount the SVR (and transformer TRAN3 when used) in unit control box. Connect per wiring schematic label on unit or per Fig. 28 (38AUZ) or Fig. 29 (38AUD).

NOTE: TRAN3 is provided with the HGBP factory installed option for 38AUDC12 units.

Evaporator Capacity Control Liquid Line Solenoid Valve: Many older unit designs included automatic capacity controls that sensed changes in suction pressure and could increase or decrease compressor capacity automatically as the evaporator load changed. Control systems were used on these units that had the thermostat’s second stage contacts control a capacity control liquid line solenoid valve to open or shutoff a portion of the evaporator surface without any direct connection to the compressor circuit.

This form of system capacity staging control is not possible with 38AU models. If this installation is a retrofit for a unit that included automatic pressure--operated unloading, check the existing thermostat and liquid solenoid valve. When found, convert the evaporator second stage solenoid control into a drop--solenoid control. Use the two SVR relays and transformer as required on 38AUD models (above); wire the SVRs and transformer per two solenoid valve systems as shown in Figs. 18 and 29.

Selecting an Accumulator –

Because all 38AU models use scroll compressors, an accumulator is not required. If an accumulator is to be added, check the accumulator manufacturer’s literature carefully for indication of its suitability for use with R--410A; look for minimum working pressure of 200 psig (1380 kPa). Select the accumulator first on the basis of its cataloged minimum capacity (tons) to ensure oil return from the accumulator, then on tube size or holding capacity.

Make Piping Connections —

Piping connections at the 38AU unit are ball valves with stub tube extensions. Do not open the unit service valves until all interconnecting tube brazing has been completed.

The stub tube connections include 1/4-in SAE service fittings with Schrader valve cores (see Fig. 11). Before making any brazed connections to the unit service valves, remove both Schrader valve caps and cores and save for re-installation. Connect a source for nitrogen to one of these service fittings during tube brazing to prevent the formation of copper oxides inside the tubes at brazed joints.

When connecting the field tubing to the 38AU service valves, wrap the valves in wet rags to prevent overheating.

Pressure-test all joints from outdoor unit connections over to the evaporator coil, using nitrogen as pressure and with soap-and-bubbles.

When pressure-testing is completed, remove the nitrogen source at the outdoor unit service valves and re-install the two Schrader valve cores. Torque the cores to 2-3 in-lbs (23-34 N-cm).

Factory High-Flow Access Port

Service Valve with Stem Cap

Field Service Access Port (Schrader core)

Sweat Connection

C150028

Fig. 11 -- Typical Piping Connection Assembly

Evacuation/Dehydration —

Evacuate and dehydrate the connected refrigeration system(s) (excluding the 38AU unit) to 500 microns using a two-stage vacuum pump attached to the service ports outside the 38AU service valves, following description in GTAC II, Module 4, System Dehydration.

UNIT OPERATION AND SAFETY HAZARD

Failure to follow this warning could cause personal injury, death and/or equipment damage.

PuronR (R--410A) refrigerant systems operate at higher pressure than standard R--22 systems. Do not use R--22 service equipment or components on Puron refrigerant equipment.

! WARNING

This unit is designed for use with Puron (R--410A) refrigerant. Do not use any other refrigerant in this system.

Puron (R--410A) refrigerant is provided in pink (rose) colored cylinders. These cylinders are available with and without dip tubes; cylinders with dip tubes will have a label indicating this feature. For a cylinder with a dip tube, place the cylinder in the upright position (access valve at the top) when removing liquid refrigerant for charging. For a cylinder without a dip tube, invert the cylinder (access valve on the bottom) when removing liquid refrigerant.

Because Puron (R--410A) refrigerant is a blend, it is strongly recommended that refrigerant always be removed from the cylinder as a liquid. Admit liquid refrigerant into the system in the discharge line. If adding refrigerant into the suction line, use a commercial metering/expansion device at the gauge manifold; remove liquid from the cylinder, pass it through the metering device at the gauge set and then pass it into the suction line as a vapor. Do not remove Puron (R--410A) refrigerant from the cylinder as a vapor.

Preliminary Charge —

Before starting the unit, charge R-410A liquid refrigerant into the high side of each 38AU circuit through the liquid service valve(s). The amount of refrigerant added must be at least 80% of the operating charge listed in Tables 5 or 6 for LINEAR line length LESS the factory charge quantity (if factory shipping charge has not been removed). See example below.

Allow high and low side pressures to equalize. If pressures do not equalize readily, charge R-410A vapor (using spe-cial service manifold with expansion device) into the suc-tion line service port for the low side of system to assure charge in the evaporator. Refer to GTAC II, Module 5, Charging, Recover, Recycling, and Reclamation for liquid charging procedures.

Example:

38AUZ*12

60-ft (18.3 m) linear line length

Equivalent line length 90-ft (27.4 m)

Liquid Lift: 20-ft (6.1 m)

Select line sizes from Table 5 (38AUZ):

Liquid 1/2 in

Suction 1 1/8 in.

Charge 23.5 lbs (at 75--ft linear length)

80% of Operating Charge:

0.80 x 23.5 = 18.8 lbs

Factory Shipping Charge: 16 lbs

Field-Charge quantity: 18.8 -- 16.0 = 2.8 lbs

For linear line lengths longer than 125 ft (38 m), contact your local Carrier representative for system charge value.

Step 7 — Install Accessories

Accessories requiring modifications to unit wiring should be completed now. These accessories may include Winter Start controls and Low Ambient controls. Refer to the instructions shipped with the accessory.

Step 8 — Complete Electrical Connections

ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal injury or death.

Do not use gas piping as an electrical ground. Unit cabinet must have an uninterrupted, unbroken electrical ground to minimize the possibility of personal injury if an electrical fault should occur. This ground may consist of electrical wire connected to unit ground lug in control compartment, or conduit approved for electrical ground when installed in accordance with NEC (National Electrical Code); ANSI/NFPA 70, latest edition (in Canada, Canadian Electrical Code CSA [Canadian Standards Association] C22.1), and local electrical codes.

! WARNING

NOTE: Check all factory and field electrical connections for tightness. Field-supplied wiring shall conform with the limitations of 63F (33C) rise.

Field Power Supply —

If equipped with optional Powered Convenience Outlet:

The power source leads to the convenience outlet’s transformer primary are not factory connected. Installer must connect these leads according to required operation of the convenience outlet. If an always-energized convenience outlet operation is desired, connect the source leads to the line side of the unit-mounted disconnect. (Check with local codes to ensure this method is acceptable in your area.) If a de-energize via unit disconnect switch operation of the convenience outlet is desired, connect the source leads to the load side of the unit disconnect. On a unit without a unit-mounted disconnect, connect the source leads to compressor contactor C and indoor fan contactor IFC pressure lugs with unit field power leads..

Field power wires…