Elect/Propane Water Heater Combo

[dkottum]

The new (and some previous Classics) Airstreams have a combination electric/propane water heater as standard equipment. Heats water fine but here is the question.

When in full hookups with water and electric, the water heater makes a "gurgle" noise when the cold or hot water is turned on, after the water has not been used for an hour or so. It looks like a "burp" of steam is escaping out the water heater pressure release valve making the noise.

Thinking of elementary physics, I'm guessing when I turn on the water, pressure is released from the hot water tank, lowering the boiling point and making a bit of steam that raises the pressure of the tank for a moment? We are in Tucson, some altitude but not much, if that matters.

Or is the damn heater just getting too hot. Or both? I don't see any heat adjustments. Anyone else?

doug k

[markdoane]

Maybe you have a diabatical water heater!

Seriously, perhaps it is cold water entering the vessel allowing steam to mix with the non-condensible gases in the headspace,

[Silver Goose]

Originally Posted by dkottum

... I don't see any heat adjustments. ...

Most modern water heaters use a small non-adjustable button shaped thermal switch that needs to be in physical contact with the tank surface or over temp can occur. The thermal switch can also be defective. I think mine has a pair of these thermal switches. Have you measured the temperature of the hot water as it comes out of the nearest hot faucet?

Do you observe this behavior in electric or gas mode?

I would ask your dealer to look at it, if they are not convenient, any repair shop authorized to service Atwood (or Suburban depending on yours) should be able to inspect and correct under warranty. I see yours is a 2012 model.

[Mike Leary]

Originally Posted by dkottum

It looks like a "burp" of steam is escaping out the water heater pressure release valve making the noise.Or is the damn heater just getting too hot.

A tiny bit of "spit" is normal. The PRV might have taken some grunge water, causing it to open. That's a pretty fresh coach, but, I'd follow the manual and drain and flush the system. The PRV should be opened, drained and "snapped" shut. Draining the system and testing the PRV should be a normal part of being self-contained.

[dkottum]

Lewster provided the solution.

The newly-filled water heater had an air bubble trapped inside, causing the gurgling sound when using the water. He suggested shutting off heating and letting the water heater cool, then opening the T & P valve (pop-off valve) until you get a solid flow of water. Then let it snap back closed. Water system is silent and heater works like a charm.

Lew knows his systems and offers good advice. Thanks Lew!

doug k