Water heater Petcock drips

[Not a Clue]

Hello,
I have been around for awhile but I don't post much. Just lurk and learn. We have a 2009 Fleetwood Fiesta 29'. We have had our share of warranty issues, but have had everything taken care of. The warranty has now expired (one year). Anyway, the last couple of times we have taken the RV camping, FHU & dry camping, when we fire up the water heater the petcock on the heater will drip. If I hit the lever to release the pressure, just tap it, it stops and is fine for the rest of the weekend. Any ideas what is causing it to drip? I am not sure the brand of water heater and the book is in the coach. Thanks for any ideas.

[Hitchhiker]

Have you tried leaving an air space at the top of the tank to allow for expansion? Read this article, it may help you understand what's transpiring when it's weeping.

[Not a Clue]

Quote:

Originally Posted by Hitchhiker Have you tried leaving an air space at the top of the tank to allow for expansion? Read this article, it may help you understand what's transpiring when it's weeping.

Thanks, that explains what is happening, I wonder why it hasn't done it before now. Unless there had been a bubble in it before and it has disappeared over time.

[Gary - K7GLD]

IF you're talking about the drain petcock, most are pretty simple in design, and inexpensive - ours did the same as yours, and needed a bit more uummmph to fully seal in the off position - looked like it had been doing the weepage bit for quite some time before we got it, no damage, just signs of water puddling and drying - and when the water is heated, expansion of the inner part of the valve became a bit worse.

Had ours out a few weeks ago to fully drain the tank for winter, valve is a simple brass-to-brass valve/seat. Easy to see where it could leak if not fully tightened. You might simply need to lean on it a bit more to seal it, or replace it with another one...

As for the pressure relief valve - we've had a few incidents with those as well - but usually just opening and closing it sharply usually is enough for it to regain a leak-proof seal...

[Not a Clue]

Quote:

Originally Posted by Gary - K7GLD IF you're talking about the drain petcock, most are pretty simple in design, and inexpensive - ours did the same as yours, and needed a bit more uummmph to fully seal in the off position - looked like it had been doing the weepage bit for quite some time before we got it, no damage, just signs of water puddling and drying - and when the water is heated, expansion of the inner part of the valve became a bit worse. Had ours out a few weeks ago to fully drain the tank for winter, valve is a simple brass-to-brass valve/seat. Easy to see where it could leak if not fully tightened. You might simply need to lean on it a bit more to seal it, or replace it with another one... As for the pressure relief valve - we've had a few incidents with those as well - but usually just opening and closing it sharply usually is enough for it to regain a leak-proof seal...

Must be the pressure relief valve, cause opening it and snapping it shut again solves the problem. Thanks

[wa8yxm]

I keep hearing about establishing an air space but I have another theory.

What's the pressure at the city water inlet?

Most RV's are designed to be feed with no more than 45-50 PSI

The city where I often parked,, fed it 80 (I used a Watts Regulator to tame it) and I've seen parks break 100 PSI.

The "petcock" as you call it. is called a TPR valve

Temperature, Pressure, Relief.

If it gets too hot (Depending on the valve 180 to over 200 degrees)

If the pressure gets too high

It vents.

[Not a Clue]

Quote:

Originally Posted by wa8yxm I keep hearing about establishing an air space but I have another theory. What's the pressure at the city water inlet? Most RV's are designed to be feed with no more than 45-50 PSI The city where I often parked,, fed it 80 (I used a Watts Regulator to tame it) and I've seen parks break 100 PSI. The "petcock" as you call it. is called a TPR valve Temperature, Pressure, Relief. If it gets too hot (Depending on the valve 180 to over 200 degrees) If the pressure gets too high It vents.

If I remember I will get a picture of it this weekend. It happens whether we are on hookups or just dry camping. It happens maybe 10 15 minutes after we turn on the hot water heater. Once I release the pressure it doesn't do it anymore. The petcock (or whatever it is) also has a what appears to be a red plastic stopper in the end of it. It is not air tight as when I release the pressure it will release with the stopper in it.

[a k]

Put a small expansion tank on your hot water supply. You can get them at Lowes. It allows the water to expand and keeps the pressure pretty constant.

[Gary RVRoamer]

Quote:

If the pressure gets too high It vents.

Indeed, that IS its function. But the TPR valve is preset to vent at 150 psi, so that is not likely to be the case here. The ECO is going to cut out before it can get hot enough to generate that kind of pressure. Or temperature either.