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Old 05-01-2022, 06:12 PM   #1
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Suburban WH pressure relief valve.

Ok, so I have a stupid question. Back in October we bought a new (2022) Salem FSX, it has a Dometic propane only water heater. We have taken it out 5 or 6 weekends now, we donít leave the water heater on all day/night, kinda only as needed. This weekend I noticed that every time I turn it on and it gets hot, it drips from the pressure relief valve until I release some pressure then maybe a hour later drips again. Is this common with the propane only WHís? My other camper has a Dometic 120/LP WH. I guess Iím trying to wrap my head around this pressure relief valve already gone bad (since itís 6 months old) already..
Ideas?
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Old 05-01-2022, 06:34 PM   #2
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Pressures increases in water heater relief valve relives pressure . I think opening the relief valve is not a good thing added stress to the spring and seal . water heater should have an air bubble at the top to absorb some pressure . I never use the tp valve on the water heater for any reason . of course it could be a temperature problem .
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Old 05-01-2022, 06:41 PM   #3
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Without any pressure in the tank you might try opening the toggle (pull straight up) and then just allowing the toggle to snap back (swipe with finger) into position. It may reset it enough. They are allowed to leak some though.
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Old 05-01-2022, 06:48 PM   #4
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Without any pressure in the tank you might try opening the toggle (pull straight up) and then just allowing the toggle to snap back (swipe with finger) into position. It may reset it enough. They are allowed to leak some though.


I actually did do that after we got back home today.. though I havenít hooked it up the the water to turn it back on to test that just yet.. thanks
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Old 05-01-2022, 07:22 PM   #5
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Replace the relief valve. Donít use it to relieve pressure. The relief valve is only designed to work once.
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Old 05-01-2022, 07:51 PM   #6
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Dometic pressure relief valve.

Quote:
Originally Posted by Nascon View Post
Replace the relief valve. Donít use it to relieve pressure. The relief valve is only designed to work once.


LOL, thanks, I might replace it if it does it again, but, youíre 100% wrong on the statement that they only are designed to work once.
I just read ( from the dometic manual) on how to reset the air pocket it the tank, is to release valve (while cold) until it pops back, all the while with the closet hot water faucet on. Pretty much what ďbubblesĒ said.. Iíll try it out tomorrow but thanks for your input.
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Old 05-01-2022, 07:58 PM   #7
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Quote:
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Replace the relief valve. Donít use it to relieve pressure. The relief valve is only designed to work once.
Where is this coming from? Even your home water heater relief valve (same as in the RV) should be tested once a year.
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Old 05-01-2022, 08:05 PM   #8
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Quote:
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Replace the relief valve. Donít use it to relieve pressure. The relief valve is only designed to work once.
Sorry you have been misinformed.

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Old 05-01-2022, 08:12 PM   #9
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As told to me by a retired union plumber and later inspector. Iím just the messenger.
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Old 05-02-2022, 09:32 PM   #10
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As told to me by a retired union plumber and later inspector. Iím just the messenger.
Probably from the same school that produces union electricians that wire a NEMA 30TT outlet for 220V.
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Old 05-02-2022, 10:47 PM   #11
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Where is this coming from? Even your home water heater relief valve (same as in the RV) should be tested once a year.
How do you test the relief valve?
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Old 05-03-2022, 06:27 AM   #12
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How do you test the relief valve?
google "how to test water heater pressure relief valve" and a plethora of how's will be available to you.
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Old 05-03-2022, 07:52 AM   #13
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As told to me by a retired union plumber and later inspector. Iím just the messenger.
Consider yourself shot!
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Old 05-03-2022, 08:15 AM   #14
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Relief valves are money makers

I'll impart a couple "tricks of the trade" at no cost to you. Now that I'm retired the 'tips" will not affect my income producing activities.

As a plumber I learned early on the way to increase sales and generate work (especially on a slow day) was to "test" the relief valve. That test procedure typically left a valve leaking in approximately 95% of the "tests."

I also learned to "NOT CREATE YOUR OWN PROBLEM." Have you ever heard the expression "lets sleeping dogs lie"? How about "if it ain't broke don't fix it"?
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Old 05-03-2022, 09:49 AM   #15
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google "how to test water heater pressure relief valve" and a plethora of how's will be available to you.
Well they say that lifting the latch and watching waywr flow is "testing" it. But how does that relate to what pressure or temperature it will actually relieve at?
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Old 05-03-2022, 10:21 AM   #16
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Well they say that lifting the latch and watching waywr flow is "testing" it. But how does that relate to what pressure or temperature it will actually relieve at?
It's not certification testing, it's testing to make sure it isn't frozen in place.
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Old 05-03-2022, 10:27 AM   #17
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You need an air pocket in the top of the water heater. Without the air pocket the hot water tends to make the pressure valve weep.

To replace the air pocket:

1. Leave the pressure valve alone. Do you mess with this at home? Didn't think so.

2. Drain and then refill the water heater by removing the anode. Leave the pressure valve alone. Turn any water pressure Off and open a faucet to depressurize the system or expect to search your lawn for the anode.)

3. Leave the pressure valve alone.

As I hope you've guessed opening the pressure release valve removes the necessary air pocket.

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Old 05-03-2022, 08:20 PM   #18
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You need an air pocket in the top of the water heater. Without the air pocket the hot water tends to make the pressure valve weep.

To replace the air pocket:

1. Leave the pressure valve alone. Do you mess with this at home? Didn't think so.

2. Drain and then refill the water heater by removing the anode. Leave the pressure valve alone. Turn any water pressure Off and open a faucet to depressurize the system or expect to search your lawn for the anode.)

3. Leave the pressure valve alone.

As I hope you've guessed opening the pressure release valve removes the necessary air pocket.

-- Chuck


Well Chuck, this is what Dometic says, and says nothing about pulling drain/anode to get the air pocket reset.. your way might work, but seems more of a PIA.
I did this and it seems too have worked so far.. if need be Iíll install a new P&T valve..

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Old 05-03-2022, 08:56 PM   #19
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The Dometic method works fine to restore the required air pocket.

But it fools with the pressure release valve and you only have to pull the release lever that one time it doesn't reset and you'll realize the need to leave it alone! Yep happened to me! Always good to drain the hot water tank occasionally (a surprising amount of crud will flush out) and that resets the air pocket automatically.

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Old 05-12-2022, 06:40 PM   #20
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Gee Iím confused, think Iíll leave mine alone as I always have.
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