Water heater relief valve dripping

Straight from the user manual:

WATER WEEPING OR DRIPPING FROM PRESSURE RELIEF VALVE

You may experience water weeping or dripping from your water heater’s Pressure
and Temperature (P & T ) relief Valve when your water heater is operating. Water weeping or dripping from the P & T Valve does not always mean the P & T Valve is defective. As water is heated, it expands. The water system in a recreational vehicle is a closed system and does not allow for the expansion of heated water. When the pressure of the water system exceeds the relieving point of the P & T Valve, the valve will relieve the excess pressure.

Suburban recommends that a check valve not be installed directly at the inlet to
the water heater tank. This will increase weeping of the pressure relief valve.
WARNING! Do not remove or plug the relief valve.

One way to reduce the frequency of this occurrence is to maintain an air pocket
at the top of the water heater tank. This air pocket will form in the tank by design. However, it will be reduced over time by the everyday use of your water heater.

To replenish this air pocket:

1. Turn off water heater.
2. Turn off cold water supply line.
3. Open a faucet in the RV.
4. Pull out on the handle of the Pressure Relief (P & T) Valve and allow water to flow from the valve until it stops.
5. Release handle on P & T Valve - it should snap closed.
6. Close faucet and turn on cold water supply; as the tank fills, the air pocket
will develop.

Repeat this procedure as often as needed to reduce the frequency of the weeping
of the P & T Valve. If the weeping persists after following this procedure, you may elect to install an expansion or accumulator tank in the cold water line between the tank and check valve to relieve the pressure caused by thermal expansion

I have seen a small leak before, and I think that is common. But if it is really dripping steady, I don't think that is normal. perhaps trash in the relief valve, replace relief valve, and or thermostat not cutting off correctly. When mine did it, I replaced the valve and the thermostat sensor. No more drip.

donn0128 wrote:
Might be as simple as no air space in the tank. Turn off the water and water heater, drain the tank completely. Open and close the relief valve a couple of times to make sure it is seated properly. Close everything. Turn the water back on. Open a hot faucet tap until you get good flow. Turn on heater and wait. If that was the problem, you should have hot water in about 30 mijutes and jo drip. If it still drips, go to a big box store and buy a new one. P&T reliev valves rarely fail, so I doubt thats the problem.

X2, most common cause and fix in my experience...

Mine aso did that. I just went to a store and bought a new one. Unscrewed it and put the new one in. Did use pipe seal and bring the old one with you to check clearance. To the cover on the unit

Many leak when heating the water. Its not a problem.

Might be as simple as no air space in the tank. Turn off the water and water heater, drain the tank completely. Open and close the relief valve a couple of times to make sure it is seated properly. Close everything. Turn the water back on. Open a hot faucet tap until you get good flow. Turn on heater and wait. If that was the problem, you should have hot water in about 30 mijutes and jo drip. If it still drips, go to a big box store and buy a new one. P&T reliev valves rarely fail, so I doubt thats the problem.