ASHRAE Standard 118.1 provides test procedures for rating directly heated commercial service water heating equipment.
The revised 2022 edition of the standard:
- Updated the scope to be consistent with the Department of Energy's July 11, 2015, final rule that establishes new definitions for "commercial" and "residential duty commercial" water heaters.
- Revised the definition of "heat-pump water heater."
- Updated the classification for Type III water heaters.
- Section 7.2, "Water Piping," was updated and defined visually in Figures 1 through 14.
- Updated venting requirements.
- Reviewed and revised all equations as appropriate for I-P and SI units.
- Revised apparatus for testing AS-HPWH with ducted discharge air.
- Revised test tolerances (Table 1).
- Updated supply water temperatures for testing heat pumps (Table 3).
- Revised test methods and calculations for all heat-pump water heaters (including air source) to be steady state, consistent with Types I, II, and III water heaters.
- Updated setting outlet water temperature for heating capacity for Types 1 through V water heaters.
- Added water heaters with multiple outlet water connections.
- Added new standby loss test method and calculations for Types II and III water heaters.
- Updated references and appendices.
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