Construction Schematics_1-23-17.pdf
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- Solicitation number
- DQ1 IHKA 2017000952 1
- Issued by
- Garfield County, Denver City, Colorado
About this file
This is a Construction Schematics document detailing proposed modifications to a domestic hot water system for an unspecified state or local facility. The project involves comprehensive piping modifications to replace and reconfigure existing boiler systems, hot water storage tanks, and distribution loops. Key components include the installation of new storage tanks (minimum 200 gallons), a single hi/lo flow thermal mixing valve (Lawler 804/model 86306), multiple multi-turn balancing valves at various connection points, and replacement of existing check valves with silent, spring-loaded alternatives. The existing boiler system consists of two Laars "Pennant" PNCH0500NACK2BJN units with 500 MBH input capacity. The scope includes demolition of existing thermostatic mixing valve assemblies, boiler water return and supply piping, storage tanks, and various valves and pumps, followed by re-piping to create identical flow paths between boilers and connections to new storage tanks. The modifications establish a common boiler injection loop with a new make-up loop incorporating the expansion tank, with all connections designed for equal length and identical fittings to ensure balanced flow distribution.
The schematic specifies detailed operational requirements including continuous operation of the circulation pump (CP-1), automatic lead/lag sequencing of both boilers cycling on and off to maintain constant hot water supply temperature of 180 degrees Fahrenheit (adjustable between 150 and 180 degrees), and weekly or hourly alternation of the lead boiler. All piping connections must be copper or brass with full-port isolation ball valves and unions at tank connections. The project requires balancing the boiler injection loop to 37.5 gallons per minute per boiler and establishing specific flow rates across multiple branch connections (5 gpm system balance, 1.5 gpm and 0.75 gpm at designated lines). Pressure specifications include 125 psig working pressure for storage tanks and 160 psig maximum for boilers, with expansion tank pre-pressurization at 40 psig. The document does not specify contract pricing, award dates, or term information.
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NOTES FOR DEMO SCHEMATIC (A)
A. SUCTION SIDE OF “GENERATING LOOP”
B. PRESSURE SIDE OF “GENERATING LOOP”
1. Incoming 3” cold water from (N) RPBP outside.
2. Remove (E) RPBP and OS&Y valves. Repair pipe.
3. (E) 2” (180 DHW) high temperature water (to kitchen & laundry)
4. Demolish (E) 2-stage thermostatic mixing valve assembly and undersized connections.
5. (E) 3” strainer to remain.
6. Demo electric high temp shut-off valve.
7. Cut 3” DCW make-up connection to 3” HWS on generating loop. Demo 3” check valve (to be replaced by new silent check valve). Maintain connection from 1” THW HWC
8. Remove 2” Boiler Water Return (BWR) and supply (BWS) from Boiler B-1 for future installation of close-coupled common 3” BWR&S at 3” HWS on generating loop. See Detail C.
9. Cut 2” (BWR &S) for Boiler B-2 at 3” HWS and cap.
10. Remove (E) ½” HWC by-pass (to TMV).
11. Remove (E) check valve and balancing valve on 2” DCW (to TMV).
12. Demo (E) 1” connection from DHW HWC (high temp) to 3” HWS on generating loop. Cap connection @ generating loop. (HWC to be extended).
13. Demo (E) or otherwise provide space for (N) multi-turn balancing valve for each of (4) THW
HWC branch connections. Remove check valves.
14. Demo (E) P-2 (supplementary THW HWC pump) and repair piping.
NOTES (CONT.)
15. Demo existing Storage Tanks.
16. Remove (E) aquastat controller for boilers. Relocate to common HWS to storage tanks (see
Detail C).
17. Demo (E) CP-1 pump assembly to provide room for multi-turn balancing valve (or replace with
(N), correctly-sized pump).
18. Demo (E) HWR/S & 180º DHW for connection to (N) tanks, typical.
NOTES FOR PROPOSED MODIFICATIONS SCHEMATIC (B)
A. SUCTION SIDE OF “GENERATING LOOP” B. PRESSURE SIDE OF “GENERATING LOOP” C. NEW COMMON BOILER INJECTION LOOP (See Detail C)
D. NEW MAKE-UP LOOP (WITH HWC & EXPANSION TANK)
1. Incoming 3” cold water from (N) RPBP outside.
2. (E) 2” (180 DHW) high temperature water (to kitchen & laundry)
3. (N) Single Hi/Lo flow Thermal Mixing Valve equivalent to Lawler 804/model no. 86306 (with vert. discharge and Optional THW shut-off & Thermometer):
a. ASSE 1017 and Leadfree certified.
b. Valve shall provide automatic protection against hot, cold or thermostat failure.
c. Bronze body employing sliding piston control mechanism. 1-1/2” DHW & DCW connection, 2” THW outlet connection.
d. 110 to 140º setpoint range. Set to 120º.
e. Provide optional Test Connection (including hose end connection, shut-off valve and thermometer).
f. Minimum 0.5 gpm flow rated (when installed in recirculation system)
g. Maximum 5 psi pressure drop @ 52 gpm; maximum 20 psi pressure drop at 100 gpm.
h. Provide manufacturer’s recommended clearance + 6-inches (for service) – above, and below valve cylinder, and integral stops.
i. Provide minimum 30” heat trap.
j. All piping smaller than indicated pipe sizes shall be threaded brass.
4. (N) ST-1 Storage Tanks. Min. 200 gallon, max. 34”Φ (O.D.), max. 93” high (inc. flexible anode rod access requirements). 125 psig work. press., ASTM P&T relief, jacketed & insulated (per ASHRAE 90.1), glass-lined steel. OUTLETS: Min. sizes on schematic plus min. 1” top or side for sensor. Provide HEV for drain @ lowest connection (if not provided on tank). Submit anode(s) selection with tank submittal (submit recent local water test from utility to tank mfr. for type selection and sizing).
5. Re-pipe boilers such that total flow pathway from each boiler are exactly the same. See Detail C.
6. Rework (E) piping assembly for CP-1 to install multi-turn balancing valve between pump discharge and isolation valve. Balance to 100 gpm. (Existing pump rated for approximately 80 gpm @ 30’ head to 140 gpm @ 12’ head – and is too large for application (without valve). Any new replacement pump shall be sized for 100 gpm @ 6’ head).
7. (E) expansion tank EX-1. Provide (N) full-port ball service valve, union, & hose end drain. Drain and pre-pressurize airside to 40 psig.
Route (N) 1-1/2” to (N) 3” make-up line.
8. (N) ¾” HWC in alignment of demo’d ½” HWC. Install (N) full port isolation ball valve and check valve as shown. Do not install a balancing valve.
9. Provide (N) 3” make-up line, and extend (E) HWS/HWR & DHW mains to connect to (N) ST-1 storage tanks as shown.
a. Mains shall be 3” full length in “header” configuration, with “tee” for each take-off.
b. All connections shall be 2” to tanks and shall be equal length with same number of fittings. Provide union and full-port ball valve and connect to threaded tank openings as shown. All plumbing copper or brass.
c. Adjust piping as necessary such that the branch piping for each tank’s service (DCW/HWR; HWS & DHW) is exactly the same as similar service for other tanks (in length and fittings); AND as similar as is practicable for each service.
NOTES (CONT)
10. Provide (N) high capacity air vent at high point of common (E) 3” DHW.
11. Provide (N) full-size multi-turn balancing valve at each existing THW HWC branch connection.
Provide @ Memory Care connection, if necessary, too.
a. Balance (E) ¾” line to 1.5 gpm.
b. Balance (E) ½” line to 0.75 gpm.
c. Balance system to 5 gpm.
12. Rework (E) piping assembly for P-1 to install multi-turn balancing valve between pump discharge and isolation valve. Balance to 5 gpm.
13. Rework (E) piping assembly for P-3 to install multi-turn balancing valve and non-slam check valve between pump discharge and isolation valve. Balance to 5 gpm.
14. Replace (E) check valve and balancing valve with new, full size multi-turn balancing valve and non-slam check valve, typical. Balance flow as recommended by TMV manufacturer (during start-up).
15. Replace (E) check valve with 3” (N) spring-loaded non-slam check valve.
ALL CHECK VALVES SHALL BE “SILENT”, SPRING-LOADED CHECK VALVES SUITABLE FOR
ORIENTATION SHOWN.
NOTES FOR BOILER PIPING DETAIL (C)
A. (E) BOILERS: Laars “Pennant” PNCH0500NACK2BJN, 2-stage copper tube with dedicated heat exchanger pumps. 500 MBH input (350 MBH output at altitude). 160 psig max. working pressure, minimum inlet temperature 120º F. [Serial No.s C 11233029 & C 12243389]
REPIPE boilers as shown to have identical flow path lengths (and pressure drops) for dedicated 2”; and common 3” BWS&R. Provide (N) or re-pipe CP-1 as shown on Schematics
1. Provide (N) multi-turn balancing valve in (E) BWR piping, typical each boiler.
2. Provide (N) non-slam check valve in (E) BWS piping, typical each boiler.
3. Provide (N) or re-use (E) controls to provide automatic lead/lag operation of boilers and control of common HWS temp to meet Sequence of Operation.
4. Balance (E) boiler injection loop for 37.5 gpm each (both pumps energized).
SEQUENCE OF OPERATION:
a. CP-1 SHALL OPERATE CONTINUALLY.
b. BOILERS B-1 & B-2 SHALL CYCLE ON & OFF AND SELECT HIGH AND LOW
FIRE TO MAINTAIN A CONSTANT HWS TEMPERATURE OF 180º (adjustable 150º to 180º)
c. STAGE BOILERS ON & OFF IN LEAD/LAG SEQUENCE AS RECOMMENDED BY
MANUFACTURER.
d. ALTERNATE LEAD BOILER ON WEEKLY (DATE) OR RUN-TIME (HOURLY)
BASIS.
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