Water heater pressure relief dripping

[lindy46]

The pressure relief valve started dripping, so I cleaned and sprayed it with WD40. Still leaked. So I bought a new unit and installed it. Still dripping! Any ideas?

[Camping family]

Did you use plumbers tape around the threads?

[bobbecky]

Your pressure relief valve is working exactly as it should. With the water inlet where you connect city water being a check valve, when the water heater is working, pressure is building up in your plumbing and has no where to go if there wasn't the relief valve, and something would burst. To stop the leaking, you need to drain water from the water heater so the water level is below the relief valve so there is an air pocket in the water heater tamk that can absorb the pressure increase. that will stop the valve from leaking for a while. You will have to do this occasionally as the air disappears, or just ignore the leaking and enjoy camping.

https://www.youtube.com/watch?v=PopWaPMra6A

[chuckster57]

Originally Posted by lindy46

The pressure relief valve started dripping, so I cleaned and sprayed it with WD40. Still leaked. So I bought a new unit and installed it. Still dripping! Any ideas?

Never spray any oils on/in the potable water system, unless it’s oil fit for human consumption.

[Ramtop]

How high is your water pressure coming into the camper? Could be too much pressure

[lindy46]

Originally Posted by Camping family

Did you use plumbers tape around the threads?

Not leaking at the threads.

[lindy46]

Originally Posted by Ramtop

How high is your water pressure coming into the camper? Could be too much pressure

On the fresh water tank and pump.

[lindy46]

Originally Posted by bobbecky

Your pressure relief valve is working exactly as it should. With the water inlet where you connect city water being a check valve, when the water heater is working, pressure is building up in your plumbing and has no where to go if there wasn't the relief valve, and something would burst. To stop the leaking, you need to drain water from the water heater so the water level is below the relief valve so there is an air pocket in the water heater tamk that can absorb the pressure increase. that will stop the valve from leaking for a while. You will have to do this occasionally as the air disappears, or just ignore the leaking and enjoy camping.

I replaced the unit so water level was below level of the valve. After installation, turned water back on with the valve open and when water started coming out, shut the valve. Let it fill then opened and closed valve quickly several times. That is how I've always done it. Didn't leak until water heated up.

[jxnbbl]

Originally Posted by lindy46

I replaced the unit so water level was below level of the valve. After installation, turned water back on with the valve open and when water started coming out, shut the valve. Let it fill then opened and closed valve quickly several times. That is how I've always done it. Didn't leak until water heated up.

Even at my house, the only time I use the relief valve with water heater maintenance/replacement is to open it up when draining the tank. I the tub/sink etc the furthest away with the strainer removed to let the air escape. This allows a natural buffer of air to remain in the tank. For an RV I guess I would use the outdoor shower if I didn't want to fill the gray tank. But if there was major plumbing work (replace the HWH) I probably would go through my normal sanitation routine and end up filling the system 2x anyways.

These relief valves leak when the there is no room for the water to expand. It usually when a boiler has a 'relief valve problem' it is a expansion tank bladder problem.

[JRTJH]

Originally Posted by lindy46

I replaced the unit so water level was below level of the valve. After installation, turned water back on with the valve open and when water started coming out, shut the valve. Let it fill then opened and closed valve quickly several times. That is how I've always done it. Didn't leak until water heated up.

The process you are using is contradictory to the process outlined in the Suburban Water Heater Manual. The same process is outlined in the Atwood manual. Essentially, what you are doing is "filling the water heater tank COMPLETELY with water and eliminating the "required air gap" which is the only means for the water heater to allow for expansion as the water heats. So, you are "forcing the relief valve to leak when you turn it on. Steps 5 and 6 in the instructions are "essentially the opposite" of what you say you're doing.

Here's the instructions for establishing an air gap from the Suburban manual. Note that the method used is to open the relief valve to allow the tank to drain below the valve level, then "snap the valve closed" and turn on the water (which forces the air to pressurize at the top of the tank). This air gap should be BELOW the relief valve, so it no longer leaks "water" but only dissipates some of the air from the air gap. As the air gap reduces, then repeat the process to re-establish the air gap. On my water heater, I re-establish the air gap about monthly when the trailer is in use and I always drain the water heater using the anode fitting if the water heater will not be used for more than a couple of weeks. This prevents the water in the tank from continuing to "corrode the porcelain lining". I would do the same on an Atwood water heater because the tank is an aluminum alloy which serves as its own anode (the tank corrodes to protect itself).

Here is the procedure from the Suburban manual:

[dutchmensport]

Agree with others.... don't bleed the air out of the water heater by lifting the pressure relief valve. Turn on a hot water faucet somewhere and let the air purge itself out, creating the necessary air pocket at the top of the water heater.

The only time that valve should be flipped open is when draining the tank. Never when filling.

[lindy46]

Originally Posted by JRTJH

The process you are using is contradictory to the process outlined in the Suburban Water Heater Manual. The same process is outlined in the Atwood manual. Essentially, what you are doing is "filling the water heater tank COMPLETELY with water and eliminating the "required air gap" which is the only means for the water heater to allow for expansion as the water heats. So, you are "forcing the relief valve to leak when you turn it on. Steps 5 and 6 in the instructions are "essentially the opposite" of what you say you're doing.

Here's the instructions for establishing an air gap from the Suburban manual. Note that the method used is to open the relief valve to allow the tank to drain below the valve level, then "snap the valve closed" and turn on the water (which forces the air to pressurize at the top of the tank). This air gap should be BELOW the relief valve, so it no longer leaks "water" but only dissipates some of the air from the air gap. As the air gap reduces, then repeat the process to re-establish the air gap. On my water heater, I re-establish the air gap about monthly when the trailer is in use and I always drain the water heater using the anode fitting if the water heater will not be used for more than a couple of weeks. This prevents the water in the tank from continuing to "corrode the porcelain lining". I would do the same on an Atwood water heater because the tank is an aluminum alloy which serves as its own anode (the tank corrodes to protect itself).

Here is the procedure from the Suburban manual:

followed the procedure from the Suburban manual and still had some dripping, but it eventually stopped. I'll see what happens.

[JRTJH]

Originally Posted by lindy46

followed the procedure from the Suburban manual and still had some dripping, but it eventually stopped. I'll see what happens.

If you've got a "well used" pressure relief valve that you've held open repeatedly to fill the tank completely with water, you may have some buildup around the relief valve seal. If so, it may leak until that buildup is broken away (if it's a calcium type solid buildup). So "snapping the relief valve lever" several times while the tank is empty might speed up removal of that buildup.

This is "just a thought" about why your current relief valve may have been leaking when you first established an air gap after not doing so for a prolonged time.

[Dipstick]

Probably needs s new flapper dapper.

[GlasNav]

Replacements are less than $20, as a matter of fact CW presently has them on sale for $16.34

[JRTJH]

Originally Posted by GlasNav

Replacements are less than $20, as a matter of fact CW presently has them on sale for $16.34

In his first post, the OP stated that he bought and installed a new relief valve. What I didn't see through the thread is whether he switch back to the old one when the new one also leaked, when he installed the new one (possibly last year ???) and any indication of which one is currently in the water heater, the old one with WD40 on it or the new one and how old the new one really is....

[GlasNav]

Just reread the OPs posts, in post 12, it stopped leaking!

[JRTJH]

Yep...

Hopefully establishing the air gap is his "end of problem fix"... If he has issues later on, hopefully he will post that as a follow up in this thread.

[bobbecky]

The reason the S/B water heaters don't have the problem like in the RV is that there usually isn't a check valve on the incoming water line, so when the water heater heats up, the excess pressure just backs up some water back into the water line coming from the street. It's the check valve on the RV where you connect your water hose that retains the water and causes the pressure to build up and makes the T&P valve vent pressure when there isn't an air pocket to absorb the expansion.

[jxnbbl]

Originally Posted by bobbecky

The reason the S/B water heaters don't have the problem like in the RV is that there usually isn't a check valve on the incoming water line, so when the water heater heats up, the excess pressure just backs up some water back into the water line coming from the street. It's the check valve on the RV where you connect your water hose that retains the water and causes the pressure to build up and makes the T&P valve vent pressure when there isn't an air pocket to absorb the expansion.

Very good point! I never thought about that.