MM700 - MECHANICAL CONTROL SYSTEMS.pdf

OCCUPIED MODE:

The occupancy mode will be controlled via a network input (OCC-SCHEDULE). The occupancy mode can also be overridden by a network input (OCC-OVERRIDE).

UNOCCUPIED MODE:

The unit will cycle to maintain unoccupied zone setpoints (CLGUNOCC-SP & HTGUNOCC-SP) during unoccupied periods.

SUPPLY FAN CONTROL:

The variable speed supply fans (SFx-C) will be started based on occupancy schedule (OCC-SCHEDULE). When either supply fan status (SFx-S) indicates a fan started, the control sequence will be enabled. The supply fans (SFx-O) will modulate in unison to maintain the duct static pressure (DA-P) at setpoint (DAP-SP). Upon a loss of airflow (SFx-S) on either fan, the fan will stop until the unit is manually reset (SYS-RESET).

RETURN FAN CONTROL:

After the supply fan has been started, the variable speed return fan will be started. The return fan (RF-O) will modulate in conjunction with the supply fan. The return fan will lag the supply fan by a percentage differential.

ECONOMIZER CONTROL:

The BAS shall use the Outside Air Temperature (OA-T) and Outside Air Relative Humidity (OA-H) along with the Return Air Temperature (RA-T) and Return Air Relative Humidity (RA1-H, RA2-H) to calculate the Enthalpies of the Outside and Return Air at any given point. When the Outside air Enthalpy is less than that of the Return Air, the economizer mode shall be enabled. The Outside Air, Return Air and Relief Air Dampers shall modulate in unison to provide the first stage of cooling in sequence with the DX Cooling Coil.

PREHEAT COIL:

The preheat (PH-O) will modulate to maintain the discharge air temperature at the discharge air temperature setpoint. When the unit is shutdown, the preheat coil will be commanded to a preset position should the outdoor air temperature (OAT) fall below the low outdoor air temperature setpoint (OALT-SP).

COOLING COIL:

The cooling coil (CLGx-C) will be staged in sequence to maintain the discharge temperature (DA-T) at the discahrge temperature setpoint.

MINIMUM OA CONTROL:

The fresh air intake of the unit will be limited to prevent the preheat temperature (PH-T) from falling below the low limit setpoint (OALT-SP).

DUCT STATIC PRESSURE SETPOINT RESET:

The BAS shall poll all terminal units every 5 minutes (adj.). If the maximum damper position is greater than 90% open, increase the duct static pressure setpoint by 0.1" W.C. (adj.) up to the maximum discharge static setpoint determined by the TAB contractor. If the maximum damper position is less than 50% open, decrease the static pressure setpoint by 0.05" W.C. (adj.) until the minimum static pressure setpoint determined by the TAB contractor.

DISCHARGE AIR TEMPERATURE RESET:

The discharge air temperature setpoint (DAT-SP) will be reset as the outdoor air temperature (OA-T) changes.

HUMIDIFICATION:

The humidifier valve (HUM-O) will modulate to maintain the return air relative humidity setpoint (HUM-SP) as sensed by the average of the two return air relative humidity sensors (RA1-H,RA2-H).

UNIT PROTECTION:

• Discharge Air High Humidity Limit – humidification shall be disabled whenever the supply air humidity exceeds 80% (adj.) as measured by the high limit humidity sensor located in the supply duct (HUMHI- A). Alarm at the BAS.

• Return Air Humidity (RA1-H,RA2-H) – the two return air humidity sensor readings shall be compared, if the difference in readings is greater than 5% (adj.) alarm at the BAS.

ADDITIONAL POINTS MONITORED BY THE FMS:

• Outdoor Air Temperature (OA-T)

• Outdoor Air Humidity (OA-H)

• Return Fan Status (RF-S)

• Prefilter Diff Pressure (PFILT-DP)

NAME DESCRIPTION SIGNAL POINT TYPE DATA TYPE

CLG1-C Cooling Stage 1 Command 24VAC Maintained Output Binary CLG2-C Cooling Stage 2 Command 24VAC Maintained Output Binary DA-T Discharge Air Temperature Nickel 1K RTD Input Analog DA-P Duct Static Pressure 0-10VDC Input Analog EAD-O Exhaust Air Damper Output 0-10VDC Output Analog OA-H Outdoor Air Humidity 0-10VDC Input Analog OA-T Outdoor Air Temperature Nickel 1K RTD Input Analog OAD-O Outdoor Air Damper Output 0-10VDC Output Analog PFILT-DP Pre-Filter Differential Pressure 0-10VDC Input Analog RA-H-1,2 Return Air Humidity 1,2 0-10VDC Input Analog RAD-O Return Air Damper Output 0-10VDC Output Analog RF-O Return Fan Output 0-10VDC Output Analog RF-C Return Fan Command 24VAC Maintained Output Binary RF-S Return Fan Status Dry Contact Maintainted Output Binary SF-O Supply Fan Output 0-10VDC Output Analog SF-C Supply Fan Command 24VAC Maintained Output Binary SF-S Supply Fan Status Dry Contact Maintainted Output Binary

The unit shall operate on an occupancy schedule as defined by the BAS.

OCCUIPED MODE:

Whenever the zone temperature sensor senses a space temperature (ZN-T) below the occupied setpoint, the unit fan is activated and the heating control valve is fully opened. Once the zone temperature rises the setpoint, the unit fan is disabled and the heating coil control valve is fully closed.

UNOCCUPIED MODE:

The unit fan shall remain off, and the hot water control valve shall remain fully closed unitl the zone temperature sensor senses a temperature below the unoccupied temperature setpoint. Upon sensing a temperature below the unoccupied setpoint, the unit fan is energized and the heating coil control valve is fully opened.

OCCUPIED MODE:

When the zone temperature is between the occupied heating and cooling setpoints inside of the bias, the primary air damper is at the minimum cfm and no mechanical heating runs.

When the zone temperature rises above the cooling setpoint, the primary air damper increases the cfm and no mechanical heating runs.

When a drop in zone temperature below the heating setpoint occurs, the supplemental heating coil is fully used before the reheat heat coil enables, and the damper opens at the minimum cfm.

UNOCCUPIED MODE:

The primary air damper is at the minimum cfm and no mechanical heating runs when the zone temperature is between the unoccupied heating and cooling setpoints inside of the bias.

When the zone temperature rises above the unoccupied cooling setpoint, the primary air damper increases the cfm (if available), and no mechanical heating runs.

When the zone temperature drops below the unoccupied heating setpoint, the supplemental heating coil is fully used before the reheat heat coil enables. The damper is at the minimum cfm.

Unit enable: A network unit enable signal, controls the mode of the box.

The unit shall operate on an occupancy schedule as defined by the BAS.

OCCUIPED MODE:

Whenever the zone temperature sensor senses a space temperature (ZN-T) above the occupied setpoint, the unit fan is activated and the cooling modes are staged in sequence to maintain the space temperature at the setpoint. Once the zone temperature falls below the setpoint, the unit fan is disabled and the heating coil control valve is fully closed.

UNOCCUPIED MODE:

The unit fan shall remain off, and the hot water control valve shall remain fully closed unitl the zone temperature sensor senses a temperature above the unoccupied temperature setpoint. Upon sensing a temperature above the unoccupied setpoint, the unit fan is energized and cooling is staged in sequence to maintain the temperature at the unoccupied setpoint.

Project Number

Building Number

Drawing Number

Project Title

Location

Issue Date Checked Drawn

Drawing Title

Approved:

VA FORM 08 - 6231

A

Office of Construction and Facilities Management

U.S. Department of Veterans Affairs

B

C

D

E

F

A

B

C

D

E

F

21 4 5 6 7 8 9 10

Phase

ARCHITECT/ENGINEER OF RECORD

A/E:

STAMPCONSULTANT

321 4 5 6 7 8 9 10

Consultant:

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.2

M E

P v c h a w k D

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P M

MM700

MECHANICAL CONTROL SYSTEMS

GUIDON

1221 N. PENNSYLVANIA STREET

INDIANAPOLIS, IN 46202

317.800.6388

EHRM TRAINING AND ADMIN

SPACE SUPPORT

5000 West National Avenue, Milwaukee, WI 53295

695-21-703

11/12/2021 CDH DQH

100% BID DOCUMENTS

FULLY SPRINKLERED

NOT TO SCALEMM700

1 TYPICAL AHU SEQUENCE OF OPERATIONS

NOT TO SCALEMM700

2 TYPICAL AHU CONTROLS SCHEMATIC

NOT TO SCALEMM700

6 TYPICAL AHU CONTROL POINTS LIST

NOT TO SCALEMM700

3 TYPICAL CUH CONTROLS SCHEMATIC

NOT TO SCALEMM700

4 TYPICAL CUH SEQUENCE OF OPERATIONS

NOT TO SCALEMM700

5 TYPICAL VAV W RH CONTROLS SCHEMATIC

NOT TO SCALEMM700

7 TYPICAL VAV W REHEAT SEQUENCE OF OPERATIONS

NOT TO SCALEMM700

8 TYPICAL DSS CONTROLS SCHEMATIC

NOT TO SCALEMM700

9 TYPICAL DSS SEQUENCE OF OPERATIONS

Revisions: Date:

LT-A 1

•Low Temperature Alarm (LT-A) - When in "Alarm", the control sequence will stop running, the valve(s) will open and the fan(s) will be disabled via a hard wired shutdown circuit.

TYPICAL OF HOT WATER COILS EXCEPT FOR NO DAMPER,

DAMPER CONTROL, NOR DAMPER SEQUENCE.

The unit shall operate on an occupancy schedule as defined by the BAS.

OCCUIPED MODE:

Whenever the zone temperature sensor senses a space temperature (ZN-T) above the occupied setpoint, the unit fan is activated and the cooling modes are staged in sequence to maintain the space temperature at the setpoint. Once the zone temperature falls below the setpoint, the unit fan is disabled and the heating coil control valve is fully closed.

UNOCCUPIED MODE:

The unit fan shall remain off, and the hot water control valve shall remain fully closed unitl the zone temperature sensor senses a temperature above the unoccupied temperature setpoint. Upon sensing a temperature above the unoccupied setpoint, the unit fan is energized and cooling is staged in sequence to maintain the temperature at the unoccupied setpoint.

NOT TO SCALEMM700

9 TYPICAL DSS SEQUENCE OF OPERATIONS10 SUMP PUMP SEQUENCE OF OPERATIONS

BAS SHALL PICK-UP MONITORING POINTS FROM SUMP PUMP CONTROLLER FOR ALARMING IN THE BAS.

Revision 1 03/21/2022