Water pressure going up with heater

[NXR]

What is the make and model of your water pump?

If you don't know what water pump you have, turn city water off and run the pump and see what happens.

Our SHURFLO 4088 water pump turns ON when the pressure DROPS to 40 PSI and turns off when it reaches 55 PSI, +/- 2 PSI.

It kind of sounds like you're trying to chase a non-problem.

Ray

[Old-Biscuit]

Originally Posted by Arizona

There is usually a back flow preventer in a fitting at the water heater. A few years ago mine broke and wouldn’t let cold water in to heat. I took it out. Since then the pressure increases on the whole system when the water gets hot. Actually pretty nice as my water filter outlet starts to drip, letting me know when I can take my shower.

Originally Posted by David 70

My inlet check valve fell apart also and stopped the water from getting into the water heater. I took it apart, removed the insides and replaced it. I've been meaning to repair it but it is a pita to get at. I've gotten a larger mid-section since then so I don't know if I could even get in there.

Winnebago is one of the FEW RV MFGs that install check valves in WH Tank Cold Inlet.
Many RV MFGs only install a check valve in HOT Outlet

My RV Water Heater didn't have ANY Check valves

Originally Posted by cm2785

So is this something that happens to everyone or no? When the heater is done there is a couple seconds of higher pressure but not much?

Yes.....it is Normal

[cm2785]

Hey guys, so I installed the accumulator tank and it seems to help a little as there isn’t a real noticeable flow from the faucet in the beginning anymore but I checked today and my water pressure going into the rig is 40psi and after the heater ran and finished it was about 58 psi, once I opened the faucet it went back to 40… is there something I’m missing here? I don’t even want to know what it was before the accumulator tank but I really want to get this resolved. Thanks!

[l1v3fr33ord1]

Christopher-

You have another thread on this issue:

Accumulator tank

Between this thread and that one, what questions are not answered to your satisfaction?

[cm2785]

Originally Posted by l1v3fr33ord1

Christopher-

You have another thread on this issue:

Accumulator tank

Between this thread and that one, what questions are not answered to your satisfaction?

Well I’ve had to replace gaskets all over because of this so I was hoping someone has figured this out. I’ve been doing alot of research and it seems like some tanks just can’t keep this air bubble, so I was hoping someone would have figured this out, maybe with a check valve or something. I’ve found and ordered a slightly cooler thermostat, but many people here had mentioned it may be normal, so I wanted to reply back after following the advice of one of the posters who mentioned to add a pressure gauge and say that I did and this is what the actual numbers are, so maybe someone could confirm if 18psi with an accumulator tank is a normal increase or not. I hope I haven’t offended you.

[Ray,IN]

Originally Posted by cm2785

Thanks guys! I am not running on the pump at the moment I am on city water, but my regulator is brand new and set to 45. I thought if the TP valve weeps a little it can allow the air bubble to be lost but maybe not leaking enough to have water come out?

Anyway, it has just been a little strange to me because I’ve had to replace three of the cone rings in three fittings that have started to drip/leak when the pressure goes up, but again, when I turn the faucet on after the heater is done it’s not like it’s blasting out of there, I can tell the pressure is a little higher for maybe two seconds but it’s not a difference enough that someone not knowing would say oh wow or anything like that… it’s just a slight bit higher pressure coming out…

That's no how the over-pressure/over-temperature device works. When you pull the lever open it expels hot water that can scald you; always turn off water supply then open a faucet to relieve pressure.
Now the T&P valve can be opened, if water is expelled there isn't enough head space/air in the tank, leave the valve open until water stops flowing. The the valve is closed by allowing the lever to snap closed.
If the valve leaks, repeat the open/close snap until it stops leaking.
RV water heaters should have a check valve on the cold water inlet, some RV mfgrs also put a check valve on the hot water outlet pipe.
Sometimes a visual reference helps:

[l1v3fr33ord1]

Christopher-

No offense taken. I just wanted to be sure what question you were asking. I believe it goes like this:

"I've had leaks in my water system. My Atwood water heater is a 10-gallon unit. I've installed a 0.75-liter accumulator and placed a pressure gauge in the water line. The cold water pressure is 40 psi. When heated from cold, the pressure rises to 58 psi. After opening a hot water faucet, the pressure drops to 40 psi. Is this 18 psi pressure rise something about which I should be concerned?"

The answer is "You should not be concerned. By itself, an 18 psi rise is not excessive, and 58 psi is within a 'nominal' range of maximum pressure for the water system. This 'shot' of water on opening a faucet after the water heater has heated the water is common."

If this is your only remaining symptom, you're OK. If others crop up, post them here, along with the pressure gauge reading(s).

[cm2785]

Originally Posted by l1v3fr33ord1

Christopher-

No offense taken. I just wanted to be sure what question you were asking. I believe it goes like this:

"I've had leaks in my water system. My Atwood water heater is a 10-gallon unit. I've installed a 0.75-liter accumulator and placed a pressure gauge in the water line. The cold water pressure is 40 psi. When heated from cold, the pressure rises to 58 psi. After opening a hot water faucet, the pressure drops to 40 psi. Is this 18 psi pressure rise something about which I should be concerned?"

The answer is "You should not be concerned. By itself, an 18 psi rise is not excessive, and 58 psi is within a 'nominal' range of maximum pressure for the water system. This 'shot' of water on opening a faucet after the water heater has heated the water is common."

If this is your only remaining symptom, you're OK. If others crop up, post them here, along with the pressure gauge reading(s).

Awesome! Thank you SO much!!

[twinboat]

Originally Posted by David 70

I use my TP relief valve all the time to vent the tank when filling or draining. I have done that on several of my rv's with no problem. Perhaps that is because it gets exercised regularly, like people say a generator needs?

Maybe reading this post will change you way of thinking about venting your water heater.