Is it the intent of R2804.1 to require tankless water heaters to have relief valves ?
P2804.1Relief valves required.
Appliances and equipment used for heating water or storing hot water shall be protected by one of the following:
1.A separate pressure-relief valve and a separate temperature-relief valve.
2.A combination pressure-and-temperature relief valve.
Interpretation #8732
Published February 15, 2023
Original Request
- Code Version
- 2021
- Code
- RESIDENT
- Code Description
- Chapter
- Section
- 2804.1
- Topic
- relief valve
Question
Answer Published 02/15/2023 at 8:56 AM
The relief valve requirements of R2804.1 and its corresponding plumbing code section 504.4 are intended to pertain to storage-type water heaters operating above atmospheric pressure. According to the IPC Commentary, this section does not address relief valve requirements for instantaneous (tankless) water heaters. Those requirements can be found in the applicable standards for instantaneous water heaters. Gas-fired instantaneous water heaters are covered by ANSI Z21.10.3, which requires overtemperature protection as part of the burner control system, and overpressure protection by installation of a pressure relief valve (normally provided by the manufacturer). Electric instantaneous water heaters are covered by UL 499, which requires overprotection to be built into the temperature control system, but does not require overpressure protection. Always refer to the manufacturer’s installation instructions.
Commentary
None.