The temperature and pressure (T&P) relief valve is the primary safety device on a storage water heater. It opens automatically if tank pressure exceeds 150 PSI or water temperature exceeds 210 degrees F, releasing hot water through the discharge pipe and preventing tank over-pressurization. Camco T&P valves meet the same ANSI Z21.22 standard as Watts, Honeywell, and Cash Acme valves and are a direct replacement for any 3/4" NPT 150 PSI/210 degree F rated valve.
Specifications
- Thread: 3/4" NPT
- Pressure rating: 150 PSI
- Temperature rating: 210 degrees F
- Standard: ANSI Z21.22 certified
When to replace
- The valve drips continuously at normal operating temperature and pressure
- The lever is corroded and will not lift for an annual test
- The valve is more than 5-6 years old as a proactive replacement
- Discharge pipe was blocked or capped -- the valve must be replaced once it has been unable to discharge freely
Annual test procedure
- Place a bucket under the discharge pipe.
- Lift the test lever and hold for 3 seconds. Water should flow freely from the discharge outlet.
- Release the lever. Flow must stop completely within a few seconds.
- A valve that continues to weep after release requires immediate replacement.
Replacement
Shut off power or gas to the heater and allow the water to cool to a safe handling temperature. Drain the tank several gallons below the valve port. Unscrew the old valve with a pipe wrench. Wrap threads with PTFE tape and install the new Camco valve. Reconnect the discharge pipe to a floor drain or exterior point. Never cap the discharge pipe.
Cost
- Camco T&P relief valve: $15-25