HELP: Suburban SW12DEL propane issue

[rvexodus]

Having an issue with my sw12del water heater on propane side. Running the burner everything is fine. Gas is flowing. Good flame in the burn chamber. Then at some point the gas starts fluttering almost as if it’s trying to shut off (not sure if that is what’s happening so don’t read into it). Flame starts to appear near the orifice in the main burner assembly (the tube where the air and gas are mixed). At this point, it makes a fluttering popping sound much like a gas flame that’s exhausting or running out of gas.

Also note worthy is my pressure relief valve started dripping (1 drop every 5-10secs). There’s some hard water deposits around the opening. Now I did flush the system around a month ago with a mild vinegar solution. So this could be unrelated to the flame issue but again worth noting. The dripping does happen even with the heater off. So I’m guessing the valve just needs to be replaced.

There was water forming around the orifice from the dripping. Was thinking maybe the water was interfering with the flow of gas but I wrapped a little foil around the pressure release valve to divert the water away from the orifice but still having the flame issue.

Hoping someone else has had a similar issue and / or can provide some recommendations.

[rvexodus]

Ok problem solved. Tried the reverse burp procedure above and that did not resolve it. I did however tap on the pin the operates the valve via the little flip up handle and simply tapping on it seated the valve enough to slow down the drip. This told me it was just a little corroded / gunned up. Could have possible cleaned it in some vinegar but had already received a replacement valve and decided to replace it. Drip drip is gone and since there’s no more water dripping on the 12v solenoid leads the flame hasn’t had any issues either.

Doug, thanks for your feedback and willingness to help. Keep up the great work. Folks like yourselves are invaluable.

[rvexodus]

dougrainer wrote:
Remember, you CANNOT compress Liquid(water), but you can compress air. You have a Dometic/Suburban WH. This type problem is rare on suburbans, but very common on Atwood WH. The Water Heater MUST have a slight air gap inside the tank. When the burner is heating, pressure in the tank builds up, but the air cushion absorbs it. NO AIR cushion and the Pop Off valve drips/seeps. It is very rare for a pop off valve to seep/weep is fairly new. Try this procedure. Doug

PRESSURE-TEMPERATURE RELIEF VALVE
Weeping or dripping of a pressure-temperature relief valve while the water heater is running DOES NOT mean it is
defective. This is normal expansion of water as it is heated in the closed water system of a recreation vehicle. The
Atwood water heater tank is designed with an internal air gap at the top of the tank to reduce the possibility of weeping
and dripping. In time, the expanding water will absorb this air. To replace the air follow these steps:
Step 1: Turn off water heater
Step 2: Turn off incoming water supply
Step 3: Open the closest hot water faucet in the coach
Step 4: Pull handle of pressure-temperature relief valve straight out and allow water to flow until it stops.
Step 5: Allow pressure-temperature relief valve to snap shut, turn on water supply and close faucet

Makes total sense. Actually I’ve had water leaks around pex connectors on the nautilus panel that only occurred while the hot water was reaching temperature. I’ve since fixed those leaks … or that’s what I thought 🙂

I did pick up a new valve but will try your suggestion before I attempt to replace it. Thank you sir. Will update this thread on the results of “reverse burping” the water heater.

[dougrainer]

Remember, you CANNOT compress Liquid(water), but you can compress air. You have a Dometic/Suburban WH. This type problem is rare on suburbans, but very common on Atwood WH. The Water Heater MUST have a slight air gap inside the tank. When the burner is heating, pressure in the tank builds up, but the air cushion absorbs it. NO AIR cushion and the Pop Off valve drips/seeps. It is very rare for a pop off valve to seep/weep is fairly new. Try this procedure. Doug

PRESSURE-TEMPERATURE RELIEF VALVE
Weeping or dripping of a pressure-temperature relief valve while the water heater is running DOES NOT mean it is
defective. This is normal expansion of water as it is heated in the closed water system of a recreation vehicle. The
Atwood water heater tank is designed with an internal air gap at the top of the tank to reduce the possibility of weeping
and dripping. In time, the expanding water will absorb this air. To replace the air follow these steps:
Step 1: Turn off water heater
Step 2: Turn off incoming water supply
Step 3: Open the closest hot water faucet in the coach
Step 4: Pull handle of pressure-temperature relief valve straight out and allow water to flow until it stops.
Step 5: Allow pressure-temperature relief valve to snap shut, turn on water supply and close faucet

[rvexodus]

Bobbo wrote:
Pay close attention to anything dougrainer says. He has been an RV technician for decades. I have seen him be wrong, but it is very, very rare.

Thanks!

[rvexodus]

dougrainer wrote:
Is the WH in a slide room? Also, oily build up in LP systems can cause a problem on just 1 appliance, if that is where the oily build up happens. Also turn on the Range LP burners on HI. Then start the Gas furnace and see what the range burners do. They should not pulsate or diminish. If they do, your LP regulator is bad. Doug

Doug, thanks for the reply. Sorry for the delayed response. Had some work to focus on.

The water heater is not in a slide out. I turned on all burners on hi and kicked on the furnace. Steady Eddy as the heater fired up as well as when it shut off. So the regulator appears ok.

Here’s where it gets interesting. My pressure relief valve was dripping. Originally, I said all the time but mainly cuz the water was hot and I’m in AZ so it takes a while to cool down. It was dripping at full heat about once per 2 secs at its worst. And it was splashing around the orifice as well as on the 12v leads going to the solenoid. No doubt a short would have effected the operation. I wrapped some tin foil around the pressure relief spigot to help redirect water away from the solenoid but apparently didn’t let it dry out enough. Today I ran the water heater with the foil redirecting the drip and everything operated properly. We topically leave the WH on all the time but at the moment for obvious reasons I have it off. I’ll run through a few more tests in the coming days as we turn the WH on as needed.

My new pressure relief valve should deliver today so I’ll replace it this weekend. Do these things just start to drip all of a sudden? I’m guessing it either has some hard water issue or it’s just weakened over time.

[Bobbo]

Pay close attention to anything dougrainer says. He has been an RV technician for decades. I have seen him be wrong, but it is very, very rare.

[dougrainer]

Is the WH in a slide room? Also, oily build up in LP systems can cause a problem on just 1 appliance, if that is where the oily build up happens. Also turn on the Range LP burners on HI. Then start the Gas furnace and see what the range burners do. They should not pulsate or diminish. If they do, your LP regulator is bad. Doug

[rvexodus]

Second Chance wrote:
I'm not sure the drip and the burner problem are related. Could the gas problem be a failing valve - like the solenoid not able to hold the valve open as long as it needs to? Do your furnace and cooktop work OK?

Rob

Thanks Rob. Yes the furnace, stove top, oven all work fine. No pulsing in the flame or anything. I did spray some soapy water on the orifice with the water heater off and there doesn’t appear to be any leakage so the solenoid appears to be closing properly.

My thoughts are:

1. Obstructed orifice or line
2. Bad regulator
3. Bad solenoid
4. Bad 12v thermostat

Not sure how to test any or if it’s just a matter of replacing 1 by 1 until the issue goes away. The orifice tube and the thermostat are cheaper and if left to just guess would be the first items I swap out.

[Second_Chance]

I'm not sure the drip and the burner problem are related. Could the gas problem be a failing valve - like the solenoid not able to hold the valve open as long as it needs to? Do your furnace and cooktop work OK?

Rob