Hot water heater???

A couple days ago we lost hot water so I looked and the pilot light went out. I lit the heater and it seemed fine. Today I went downstairs and the floor was wet. The water heater was dripping from the T&P valve so I shut the water off to the heater and opened a tap to relieve the pressure. I also opened the T&P to release a little water, into a bucket, and hopefully get it to seal better. It is sealing better but still has a very tiny slow leak. I've heard they can leak a little if the heater goes out. I'll check tomorrow but if it's still leaking, is it best to replace the T&P valve? Thanks. Dave

They as well as the drain valve at the bottom often leak if the water cools down but normaly reseal when water gets hot again. If it doesn't seal within a couple hours,you may as well change t&p valve. Now to the heater going off. There is a remote but dangerous possability the heater went off on over heat protection. For that reason DO NOT PLUG OR OTHERWISE CERCUMVENT T&P VALVE even temporarly. If the heater keeps going out,the two most common causes are #1 Thermocouple ($5 part) #2 Something changed at vent like cap fell off or strong wind or out of unusual direction blew pilot out.

Turn the water back on and fill the heater. Especially if the burners still on!

Just like Da-Bees said it's probably a good idea to go ahead and change the T&P. They're basically designed to be a one time use valve. You take your chances on them resealing after they've blown off.

Is the combustion chamber of your heater sealed off and you have an igniter button to light the pilot? This would be a heater that is probably 6-10 years old I'm thinking??? What I'm getting at is your heater draws air from the base somewhere and should have a removable plastic screen/filter. This may be clogged with dirt or lint and would have caused the pilot to go out.

For no more then they cost Id also consider simply replacing the T & P relief valve. Ive seen many that once they start trickling they dont seal back well. Just turn the water off n drain her down enough n replace it (it dont hurt to turn of the power just in case). Its a good thing to have a drain available at the bottom drain valve and now n then drain n flush them so maybe calcium n crud n lime etc dont accumulate up high in the tank.

John T

I can't imagine any way the pilot light going off can cause the TP valve to leak. I don't doubt it's happening, but don't believe the order of cause-and-effect. More likely some problem caused both to happen, and neither caused the other.

I'm wondering what caused your pilot to go out. Bad thermocoupler? Or thermal shut-down?

As to the TP valve leaking at the same time as no pilot - perhaps a thermal trip in the gas valve because the water got too hot?

All gas heaters have a one-time blow thermal fuse that will go if it really gets hot. But, since you got your's going again, seems something else is going on. The reality is, the water should never have gotten hot enough to trip that TP valve - so either the thermostatic control is bad, or the TP valve is bad.

By the way, my 80 gallon hot water tank that is primarily heated by a wood furnace has dual TP valves on it. I have to replace one or both at least once every winter. That because when my thermo-siphon coils get partially plugged with sediment, and flow slows down, the water overheats. I've found that I can reset the TP valve a few dozen times before they become chronic leakers and I have to replace them.

Are you on rural water that uses a pressure regulator in the meter pit? That's also a check valve and won't allow water to go back to the main when it expands when heated. That will pop the T&P valve often. In that case you need a small expansion tank, probably a couple gallon size some where on the cold water line.

Replacing the T&P valve won't fix this problem.

Gerald J.

Can't help on the T&P. A partially plugged pilot jet can cause a no-fire situation. A plugged jet can make a pilot that is too weak to keep the thermocouple warm enough and it could blow out just from the air draft. Look at the pilot flame to see if it's small and lazy and not making a big enough flame to touch the thermocouple.

This might not be the cause of your problem but it's easy to check out. If you do want to clean the pilot jet do not ream the holes. The larger flame will burn out the thermocouple. Don't ask how I know. Jim

I put a bucket under the hose on the T&P valve and have about 3/8" of water in it after about 12 hours. Otherwise it's working fine. I'll keep monitoring it to see if the leak stops or gets worse. Thanks. Dave

City water. Dave

Many cities are now requiring an antibackflow device on the supply line from the city. This prevents contamination if the city loses pressure.

The expansion tank is a great idea. If they put that valve on my house, I'm getting the tank.

I always thought those things were called "Cold water heaters??" Ya don't have to heat "hot water" do ya? HMMM??

Replace the T&P valve, on my rent houses I always keep a spare around because occassionally one will begin to leak. I have all of my heaters under the house in the house in the crawl space, and I have had that happen and it is a mess. So I have run a line to the outside so I can see if they are leaking. These are not on old heaters because I built or moved all of these houses and everything was new. Doesn"t happen often but I have replaced three so far. They are all electric heaters and are functioning as designed.

Water actually feels "hot" to me above 105* or so. My "hot water" heater kicks on about 115* or so and goes up to 125*. Therefore, I for one have a "Hot" water heater because it actually heats water that is hot to a higher temperature. Old discussion at work that I finally won. Just my 2 cents.
HHHHMMMMMMMMMMMMM.

Mike