Revised SPECIFICATIONS 657-27-107

SECTION 22 34 00 – Domestic Water Heaters (DHW Generator Systems)

SECTION 22 34 00

DOMESTIC WATER HEATERS (DHW GENERATOR SYSTEMS)

PART 1 – GENERAL

1.1 SUMMARY

A. Provide complete Domestic Hot Water (DHW) Generator Systems including semi‑instantaneous or instantaneous steam‑to‑water double‑wall heat exchangers; DHW storage tanks; DHW recirculation pumps; thermostatic mixing valves; expansion tanks; steam PRV stations, traps and condensate accessories; instruments/sensors; BAS/ECC integration; commissioning; flushing/disinfection; and all incidental work to deliver a fully functional, code‑compliant DHW system.
B. Design, products, and installation shall comply with VA PG‑18‑10 requirements for DHW systems, including temperature control, Legionella mitigation, recirculation, commissioning and BAS monitoring.

1.2 RELATED REQUIREMENTS

A. Section 22 11 00 – Facility Water Distribution (piping, valves, insulation, identification). B. Section 01 35 26 – Safety Requirements (shutdowns, escorts, ICRA). C. Section 13 05 31 – Seismic Restraint Requirements (equipment and piping).

1.3 REFERENCES

A. VA Plumbing Design Manual PG‑18‑10 (September 1, 2026). B. VA Design Submission Requirements PG‑18‑15.
C. VA Seismic Design Handbook H‑18‑8.
D. ASSE 1017 (Master Thermostatic Water Mixing Valves), ASSE 1016 (Combination Pressure‑Balancing/Thermostatic Shower Valves), ASSE 1070 (POU tempering valves). E. AWWA C651 (disinfection).

1.4 ADMINISTRATIVE REQUIREMENTS

A. Coordination: Coordinate shutdowns, phasing, escorts, and infection control with COR/CO per Section 01 35 26.
B. Pre‑installation meeting: Review rigging routes, access/maintenance clearances, BAS points, commissioning sequence, and eradication test procedures; record minutes.

VA St. Louis HCS – John Cochran Division | Project 657-27-107JC

SECTION 22 34 00 – Domestic Water Heaters (DHW Generator Systems)

1.5 SUBMITTALS

A. Product Data: Heat exchangers (double‑wall), DHW tanks, recirculation pumps, thermostatic mixing valves, expansion tanks, steam PRVs/traps/condensate units, instruments and BAS devices. B. Shop Drawings: System layout; piping schematics with valves/bypasses; equipment rigging and maintenance clearances; control diagrams; BAS/ECC point lists and alarm matrix. C. Calculations: expansion tank sizing; recirculation balance (heat‑loss method); eradication flow verification (≥30 gpm at 170–180°F).
D. Commissioning Plan: Functional tests, BAS trending, temperature verification, eradication run, and disinfection plan.