Slow but steady drip from Hot Water Heater

[Jillian]

Hi everyone,

Took my Forester out for it's maiden voyage and discovered a slow, but steady drip coming from the water heater. I hadn't previously noticed it, so it could be intermittent. The culprit is this brass valve pictured here. I tried to press it in (what a [literal] hot mess!) to reset it but it still seemed to drip at stead rate. You can see some of the spray on the back panel.

The heater was on electric mode. Anything I can do or should I just accept this slow drip?

[ependydad]

I believe that if you open that and let a fair bit of water come out, it'll restablish an air pocket and that should stop the water from dripping.

https://www.google.com/search?q=subu...ter+air+pocket

[phillyg]

The pressure relief valve spring is probably too weak and can't provide a good seal; easy to replace.

[HangDiver]

Since its new I'll bet there was some construction debris left in one of the water lines and its stuck in the pressure relief valve. I would turn the HW heater off and let the water cool some (so you don't burn yourself), then throttle that pressure relief valve lever open and closed a few times to hopefully free up whatever might be stuck in there, if that is indeed the case.

Congratulations on the new camper.

EDIT: After reading ependydad' post again, that may resolve your issue. Good luck.

[Bill and Gail]

X2

Originally Posted by ependydad

I believe that if you open that and let a fair bit of water come out, it'll restablish an air pocket and that should stop the water from dripping.

https://www.google.com/search?q=subu...ter+air+pocket

[Jillian]

Thanks for the responses! I'll give this solution a try and report back.

[Larry-NC]

The real reason for a drip from the temperature/pressure valve is simply expansion of cold water when it is heated. It often happens when you are connected to city water via a backflow preventer.

It happens less frequently when you are using water from the fresh water tank since the initial pressure is lower. Nothing is broken. Nothing needs fixing.

[Witch Doctor]

Originally Posted by Larry-NC

The real reason for a drip from the temperature/pressure valve is simply expansion of cold water when it is heated. It often happens when you are connected to city water via a backflow preventer.

It happens less frequently when you are using water from the fresh water tank since the initial pressure is lower. Nothing is broken. Nothing needs fixing.

really? I been owning some sort of TT or MH for over 20 years. I never had that problem, but I do open it when the water is cold and hooked to city water, it resets the seal . To say this offend happens means somebody didn’t understand the purpose of the valve or the operation of the water heater. I agree with letting cool and open it a couple of times to reseat it. I might have heard of 1 or 2 times it needed to be replaced. It shouldn’t leak at all.

[Larry-NC]

Originally Posted by Witch Doctor

really? I been owning some sort of TT or MH for over 20 years. I never had that problem, but I do open it when the water is cold and hooked to city water, it resets the seal . To say this offend happens means somebody didn’t understand the purpose of the valve or the operation of the water heater. I agree with letting cool and open it a couple of times to reseat it. I might have heard of 1 or 2 times it needed to be replaced. It shouldn’t leak at all.

This has been discussed a bunch of times on this forum. City water is at a relatively constant pressure based on the height of the water level in the city water tank above the trailer ("head"). If you are hooked up to city water (home or trailer), when the water in the heater expands you simply push a few ounces of clean fresh water back into the main.

That is, until some uneducated bureaucrat in Washington decides that this is somehow dangerous. Then backflow preventers ("check valves" or "one-way valves") get installed all over the place. When that happens, the water in the heater can expand enough to exceed the release pressure of the Temperature & Pressure safety valve. The valve does what it is supposed to do and relieves the excess pressure.

The little volume at the top of the 6-gallon tank is not enough to account for six gallons expanding, and there's virtually nothing else to expand (maybe the hose feeding the trailer from the city water tap). In your home or in your trailer, the only solution is to install a additional, larger expansion tank somewhere on the system. It should be on the cold side (for longer lifetime) and can be anywhere in the system (since pressure is constant throughout).

Depending on the local pressure, the need could be greater or lesser. Around here, the city water pressure is 140 psi. Every homeowner is expected to install Pressure Reducing Valve (PRV) to take the pressure down to about 70 psi. I can assure you that when the PRV fails, all you have to do is run the dishwasher or a load of wash and several minutes later you will see water from the T&P valve. I finally gave in and installed a 2-gallon Expansion tank.

My 2-gallon tank is rated for water heaters up to 50 gallons. Scaling this,
2 *6/50 = .24 gallons = 1 pint. The air space at the top of the SW6Dxx series of heaters is barely a pint (visually) and is therefore marginally adequate. You would most likely see this when the water is really cold.

[Witch Doctor]

Originally Posted by Larry-NC

This has been discussed a bunch of times on this forum. City water is at a relatively constant pressure based on the height of the water level in the city water tank above the trailer ("head"). If you are hooked up to city water (home or trailer), when the water in the heater expands you simply push a few ounces of clean fresh water back into the main.

That is, until some uneducated bureaucrat in Washington decides that this is somehow dangerous. Then backflow preventers ("check valves" or "one-way valves") get installed all over the place. When that happens, the water in the heater can expand enough to exceed the release pressure of the Temperature & Pressure safety valve. The valve does what it is supposed to do and relieves the excess pressure.

The little volume at the top of the 6-gallon tank is not enough to account for six gallons expanding, and there's virtually nothing else to expand (maybe the hose feeding the trailer from the city water tap). In your home or in your trailer, the only solution is to install a additional, larger expansion tank somewhere on the system. It should be on the cold side (for longer lifetime) and can be anywhere in the system (since pressure is constant throughout).

Depending on the local pressure, the need could be greater or lesser. Around here, the city water pressure is 140 psi. Every homeowner is expected to install Pressure Reducing Valve (PRV) to take the pressure down to about 70 psi. I can assure you that when the PRV fails, all you have to do is run the dishwasher or a load of wash and several minutes later you will see water from the T&P valve. I finally gave in and installed a 2-gallon Expansion tank.

My 2-gallon tank is rated for water heaters up to 50 gallons. Scaling this,
2 *6/50 = .24 gallons = 1 pint. The air space at the top of the SW6Dxx series of heaters is barely a pint (visually) and is therefore marginally adequate. You would most likely see this when the water is really cold.

all that is find and dandy, but in all my years at home or a CG it has happened once to me. Don’t mean to say your wrong but I have never but once experienced it and I just open and closed it and it reset, people over think simple things was my point only you have an opinion and that is great but other do to.

[KyDan]

Turn off water supply.
Open faucet to relieve pressure.
Open drippy valve on water heater all the way and let it
snap shut.
Turn water supply back on.
Go get a cold one and happy camping!

[campers302]

Originally Posted by Jillian

Hi everyone,

Took my Forester out for it's maiden voyage and discovered a slow, but steady drip coming from the water heater. I hadn't previously noticed it, so it could be intermittent. The culprit is this brass valve pictured here. I tried to press it in (what a [literal] hot mess!) to reset it but it still seemed to drip at stead rate. You can see some of the spray on the back panel.

The heater was on electric mode. Anything I can do or should I just accept this slow drip?

Before you do anything else, be sure to turn the heater off, turn off the water to the TT outside, open the hot water faucet to relive pressure on the tank. Now go out to the heater and flip the lever on that valve a few times letting it snap into place. Many times something will get caught just enough to hold it open just enough. A piece of sand, calcium etc.
Good luck.

[NJKris]

yup, just work the valve. something preventing good seal. I exercise my valve routinely by opening valve as I fill water heater to let most of air vent out. I don't flood entire tank, because it's important to have a little air at top of tank for expansion. As soon as a little water begins to spit out, I let it snap back shut. I also hold that valve open when draining the tank so it comes gushing out nice, pulling mineral deposits out as it drains.

[NavyLCDR]

About all of this talk about backflow preventers. Every RV that I know of has the backflow preventer built into the city water connection at the outside wall of the trailer. That's what keeps water from spitting out the city water connection when you are not connected to city water and running off your water pump.

[KyDan]

Just in case no one has mentioned it.... open the drippy valve and let it snap shut. (but you should turn off water supply and relieve pressure first.)
Just thought I'd mention that.... you know.... in case it hasn't come up yet...

[5picker]

Originally Posted by KyDan

Just in case no one has mentioned it.... open the drippy valve and let it snap shut. (but you should turn off water supply and relieve pressure first.)
Just thought I'd mention that.... you know.... in case it hasn't come up yet...

This thread only has 15 posts but I'm not going to read through them.
I don't know if this was mentioned or not but I agree with Dan.... open the T&P valve and let it snap shut.

[campers302]

Originally Posted by Jillian

Thanks for the responses! I'll give this solution a try and report back.

Ummm, so, what did you find?

[Jillian]

Originally Posted by campers302

Ummm, so, what did you find?

I tried the trick mentioned above to open the valve (after turning off the heater and relieving pressure) and letting it snap shut. i did this about six times. We'll see how it worked this upcoming weekend!

[NJKris]

wouldn't be a bad idea to let heater fill up with water till it is gushing out of relief valve to flush possible debris out, then release some of the water out of anode hole to re-establish air cushion at top of tank.

[Larry-NC]

Originally Posted by NJKris

wouldn't be a bad idea to let heater fill up with water till it is gushing out of relief valve to flush possible debris out, then release some of the water out of anode hole to re-establish air cushion at top of tank.

You have it exactly backwards there, Kris.

The debris in the bottom of the water heater has the nearly the density of gravel. You are not going to magically float it out the relief valve. To get it out you have to bypass the water heater, remove the anode rod, and and flush it. Some people use a wand, I just spray in with a hose nozzle. I suppose you could also turn the water on with the anode rod removed and flush it back to front. (If you are thinking there's debris in the T&P valve, just opening it under pressure should be enough to flush it.)

The T&P valve (on one end) and the hot water outlet (on the other end) are not at the absolute top of the tank. They are both down just a little from the top. The air cushion is automatically established. If it needed to be re-established, you could turn the water off and open the T&IP valve. Any water above the valve level would run out as air is drawn in through the valve (glug, glug). You could speed this up by opening a hot water tap at the same time. Three steps.

• Water off
• Open hot water tap
• Open T&P valve until flow stops.