Water Heater Relief Valve

Are you looking for information on water heater relief valve? On this

page you'll learn what a hot water heater relief valve is, how to check it,

how to replace it and what you should do if its opening on its own.

TPR Valve

Temperature and pressure relief valve.
Also known as- t&p; valve (temperature and pressure) valve
and tpr valve (temperature pressure relief) valve.

water heater relief valve

Water heater pressure relief valves
are safety devices designed to relieve
pressure from a water heater in case
of extreme temperature/pressure rise.

Water expands as it is heated.
If a water heater thermostat
malfunctions and continues to heat
water non stop the tank would eventually explode if it didn't have a
relief valve to relieve the pressure.

Watch a water heater explosion when the pressure relief valve fails.

Why is water slowly leaking out of the relief valve discharge (drain) line?

The pressure relief valve itself may be the problem, especially if its
an older valve.

Relief valves will release water slowly if their is to much pressure in the tank. This happens on closed water systems ( check valve somewhere in the system).

First replace your relief valve if it is an older one. If the new valve is allowing water to leak out you may need to install an expansion tank on the cold water inlet line near your water heater.

Expansion tanks are designed to absorb the pressure from your water heater.

The water pressure regulator valve may be at fault.

Why is my relief valve sporadically releasing large amounts of water?

This happens when the valve is opened because of high temperatures.
Replace faulty thermostat.

How to check a tpr valve

1. To check for a leaking valve feel
the drain line with your hand to see if
its hot (see pic). The drain line may
be warm near the valve, this is normal.
If the line is hot the relief valve is opening.

2. Raise the test lever on the
relief valve (see pic).
You should hear water discharging
out the relief valve drain line.
If you do then your valve is working

If you do not hear a discharge or your test lever 

won't raise (don't force it) replace the relief valve

as soon as possible.

Check your water heater relief valve at least once or 

twice a year to be sure its working properly.

How to replace a water heater relief valve

Electric water heater - turn the water heater breaker off.

Gas water heater - set the temperature knob to its lowest setting.
Turn the control knob to the pilot setting.

Turn the water supply off at the water heater.

Open the nearest hot water faucet to relieve the pressure on the tank.

If the pressure relief valve is mounted on the side of the tank you'll have to

drain the tank until the water level is below the valve.

If the relief valve is mounted on top of the tank your ready to start.

How to replace a relief valve

Remove the drain line that's
attached to the relief valve.

Cut the line and unscrew it
from the relief valve.

Remove valve with an adjustable wrench

You can remove the relief valve
with an adjustable wrench. Tap the
end of the wrench with a hammer
to loosen the valve.

Lift tpr valve from water heater

Remove the old relief valve.

Install new relief valve

Use telfon tape or pipe dope
and install the new relief valve.

Reinstall the valve drain line.

Refill the water heater. Leave the hot water faucet open until

all the air is out of the line. Check for leaks.

Electric water heater - turn the power on.

Gas water heater - set the control knob to the on position.
Turn the temperature control knob to the normal setting.

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