Water heater relief valve.

[Skypod]

Hi all
I have a Surveyor Legend. When I select electric hot water every time it trips the pressure relief valve and I get about a quarter of a cup of water that comes out. I do not have this problem when I use propane to heat the water. Any suggestions or thoughts would be greatly appreciated thank you.

[Skip12]

You may get other opinions but if if only happens once per trip, I wouldn't give it a second thought..

[Capt. Mike]

I think what the OP is saying is that it happens every time he tries to run his water heater on electric, but does not happen when he runs the water heater on propane.

You don't say what year your Surveyor is. Did you buy it new or used? Maybe somebody before you put in the wrong heating element and it is overheating the water. That will make the pressure relief valve "pop".

[nomad297]

Originally Posted by Capt. Mike

Maybe somebody before you put in the wrong heating element and it is overheating the water. That will make the pressure relief valve "pop".

Using the wrong element wouldn’t make a difference in this case. The thermostat will shut down the power to the element once it reaches temperature no matter which element is installed.

I would start by measuring the temperature of the hot water. If it gets up to 210 degrees, the T&P valve will open, as it should. This will tell you that you have a malfunctioning thermostat. If the T&P valve opens at less than 210 degrees, the T&P valve could be bad or the the water is getting hot enough to increase the tank (and system) pressure to above 150psi.

Since it is only happening when being heated with electricity, and not happening when being heated with propane, I would guess that the thermostat needs to be replaced. It sounds like the thermostat for the propane side is shutting down when it is supposed to and the thermostat for the electric side is not.

Bruce

[FleckDreher]

You may have an air bubble in the heater tank at the relief valve.

Try manually burping the valve to release the air before turning on the electric heater element.

[nomad297]

Originally Posted by FleckDreher

You may have an air bubble in the heater tank at the relief valve.

Try manually burping the valve to release the air before turning on the electric heater element.

No.

Bruce

[Sealyn]

Originally Posted by FleckDreher

You may have an air bubble in the heater tank at the relief valve.

Try manually burping the valve to release the air before turning on the electric heater element.

This is actually backwards, an air pocket in the top of the tank is needed as an expansion area when the water heats. Dripping from the valve is fixed by opening when the tank is cold and releasing water reestablishing the air pocket. Read the manual.

[FleckDreher]

The thermal performance of the relief valve is based on "water" being present at the valves thermal element.

If no water is present the valve will not operate as designed.

It's designed thermal performance conditions will not be satisfied.

That is why it works after opening once.

Believe it or not.

[Sealyn]

Water level is at the valve, but proper operation requires an air pocket in the tank. This is maintained by opening the valve and letting excess water drain from the tank, per the operating manual. Believe it or not.

[FleckDreher]

My explanation is correct.

You may not understand it.

[rockfordroo]

Assuming you have a Suburban WH (you never said who made it), you have two thermostats; one for the 120VAC electric element and a 12VDC one for the gas. Never of of it before, but it's POSSIBLE that the T-stat for your electric has drifted high somehow. However, the standard T-stat is set to 130F, but they also make a 140F T-stat, so it seems doubtful that could be your problem.

In the past, I've found the Suburban part numbers below.

The first 2 are what you should have as standard. The next two are the hotter ones. I could only find one lower one; I THINK 120VAC, but not certain.

Standard
232306, 130 deg, 120VAC
232282, 130 deg, 12VDC

Higher
232319, 140 deg, 12VDC
232317, 140 deg, 120VAC

Lower
520788, 120 deg, 120VAC??

You could also try replacing the TP valve.

[MR.M]

Originally Posted by FleckDreher

You may have an air bubble in the heater tank at the relief valve.

Try manually burping the valve to release the air before turning on the electric heater element.

If there was a air bubble as you put it . T&P valve not immersed in water then how does he lose water out of it when on electric ?

[Sealyn]

Originally Posted by FleckDreher

My explanation is correct.

You may not understand it.

It seems that several others here are also so dense that we realize you are the one that is wrong. As in your signature, read the manual, by design, the water level will be above the valve and opening it is to let excess water (not air) out of the tank.

[Mr. Dan]

The site team has closed this thread while we review several guidelines violations.

[wmtire]

OK, the T&P valve (which stands for Temperature AND Pressure) will open if the temperature and/or the pressure gets too high. Higher temperatures will also result in higher pressures.

There may be some confusion, but it appears some are talking about temperature and some are talking about pressure. I think everyone is correct in their own way.

Suburban/Aircel sent us over some great videos awhile back on the operation and use of their brand of tank type water heaters. If the OP has an Atwood/Dometic brand I would feel they would operate in a similar fashion. We keep all 5 of the Suburban videos as a sticky in the FAQ subsection at this link.

http://www.forestriverforums.com/for...es-135977.html

Mark Polk explains the function/use of the T&P valve, as well as the valve dripping. Here it is again below:

Water Heater Series 01: Video 02 – Pressure Relief Valve Function

https://www.youtube.com/watch?v=ilEt4PROv2A&t=14s

The fact it is doing it only on electric is kind of interesting. The thermostat and the hi-limit/ECO thermostat would both have to fail for the temp to get over 165 degrees (but this could happen easily if the thermostat assembly was not snug against the tank wall and ASSUMING the OP has a Suburban). I would think the OP would notice if the water was that hot as it would be unbearable.

Anyhow, we are going to reopen this thread. Please remember that this is a friendly forum, and we are all here to share collective wisdom. You may disagree with someone else's opinion, but it's 'HOW" you express this disagreement that's key.

[Skypod]

Thank you all for your replies. I will work this tomorrow. It’s a new 2019 Survey legend. I’ll test the water temperature. I always felt that it is very hot. Has anyone changed out the temp limit switch?
Thanks