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Author Topic: Hot water overflow  (Read 14083 times)

Tom

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Re: Hot water overflow
« Reply #30 on: March 13, 2005, 07:50:35 PM »
Thanks all for the help. I didn't get to look at the problem this weekend, but will be getting to it during the week.
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Ron

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Re: Hot water overflow
« Reply #31 on: March 13, 2005, 09:44:03 PM »
Does the water still leak out before you turn on the water heater?  If it doesn't it is a pretty good indication you have NO head of air in the water heater.
Ron & Sam-home is where we park it. Currently located   HERE

Tom

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Re: Hot water overflow
« Reply #32 on: March 13, 2005, 10:08:34 PM »
Ron

It only comes out when the heater has been on for some time. If I then shut off the heater and run a hot faucet for a short while, effectivly cooling the water in the tank, it stops. That's why I originally thought the thermostat wasn't doing its job and the water overheating.
« Last Edit: March 13, 2005, 10:10:10 PM by Tom »
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Ron

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Re: Hot water overflow
« Reply #33 on: March 13, 2005, 10:19:15 PM »
As the water it expands with nor head of air the water cannot compress so the excessive pressure causes the pressure relief valve to open.  First thing I would recommend is restore a air head by either opening the pressure relief valve till the water stops runnng out or using one of the other recommended in this thread.  I'm quite sure that will correct the anomaly.
Ron & Sam-home is where we park it. Currently located   HERE

Tom

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Re: Hot water overflow
« Reply #34 on: March 13, 2005, 10:24:25 PM »
That should be easy to try Ron (and free).
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Ron

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Re: Hot water overflow
« Reply #35 on: March 13, 2005, 10:25:18 PM »
Not even consultation fees. ;D
Ron & Sam-home is where we park it. Currently located   HERE

Lou Schneider

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Re: Hot water overflow
« Reply #36 on: March 14, 2005, 02:33:43 AM »
You can put a head of air in the hot water heater, but that's really just a band-aid.

The real problem is the RV has a sealed water system , with checkvalves at the water pump and at the city water system.   The water in the hot water tank expands as it heats up.  In a conventional house the expanding water can backflow into the cold water inlet line, eventually dissipating through the main water inlet to the house.   In a RV the checkvalves prevent backflow, so when the water expands in the hot water tank, there's nowhere for it to go.  The system pressure rises until the overtemp/overpressure valve weeps.

An air bubble in the top of the hot water tank will eventually be absorbed into the water.   The permanent solution is to install an accumulator tank on the cold water side of the system.  The accumulator has a membrane seperating the air from the water so the air pocket stays intact.  The easiest place to install an accumulator is usually at the outlet of the water pump, but it could be installed anywhere in the system.  The permanent airspace in the accumulator gives the expanding water some place to go, so the system pressure stays normal instead of popping off the overflow valve.
« Last Edit: March 14, 2005, 02:35:54 AM by Lou »

Tom

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Re: Hot water overflow
« Reply #37 on: March 14, 2005, 03:04:34 AM »
Lou

I have an accumulator tank after the dual water pumps. Now you have me wondering why it doesn't act as the equivalent of an air pocket and allow expansion of the water.
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Ron

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Re: Hot water overflow
« Reply #38 on: March 14, 2005, 09:04:34 AM »
You have to make sure there is no check valve between the accumulator and the water tank. What Lou mentioned about the head of air dissipating happens.  However, in our case between letting air from the hose enter the system as some described ealier and flushing the water heater twice a year we never have any trouble with the head of air in the water heater dissipating.

Ron & Sam-home is where we park it. Currently located   HERE

Tom

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Re: Hot water overflow
« Reply #39 on: March 14, 2005, 09:16:28 AM »
OK thanks Ron. Looks like I have long list of stuff to fix &/or install this week (month?)
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Ned

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Re: Hot water overflow
« Reply #40 on: March 14, 2005, 09:54:35 AM »
Ask me at Moab about my adventure in draining the HWT last summer.
-- Ned -- Fulltimer 1997-2013
1997 Holiday Rambler Endeavor LE
2007 GMC Canyon

Tom

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Re: Hot water overflow
« Reply #41 on: March 14, 2005, 09:55:32 AM »
Will do Ned. Do I see a HFWPOH award?
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Ned

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Re: Hot water overflow
« Reply #42 on: March 14, 2005, 10:21:28 AM »
No, just a simple job gone awry.  It involves the relief valve, too, and the rule "Never start a plumbing job on a Sunday".
-- Ned -- Fulltimer 1997-2013
1997 Holiday Rambler Endeavor LE
2007 GMC Canyon

Karl

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Re: Hot water overflow
« Reply #43 on: March 14, 2005, 06:01:41 PM »
I'll second that, and never remove (or try to remove) a nylon drain plug unless you already have a new one. And plan on spending a few hours removing the old one after you've twisted the head off it with a wrench.
Karl (Cheesehead) Kolbus   Life's journey is not to arrive at the grave safely in a well preserved body, but rather to skid in sideways, totally worn out, shouting "...holy cow ...what a ride!"

Ned

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Re: Hot water overflow
« Reply #44 on: March 14, 2005, 06:10:44 PM »
I broke the nylon plug in Louisiana a few years ago.  This episode involved the relief valve.
-- Ned -- Fulltimer 1997-2013
1997 Holiday Rambler Endeavor LE
2007 GMC Canyon

Ron

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Re: Hot water overflow
« Reply #45 on: March 14, 2005, 07:03:36 PM »
I broke the nylon plug in Louisiana a few years ago.  This episode involved the relief valve.


Does that mean rule two is to have a spare nylon plug when ever you drain & flush the tank? ::) ??? ::)
Ron & Sam-home is where we park it. Currently located   HERE

Ned

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Re: Hot water overflow
« Reply #46 on: March 14, 2005, 09:58:10 PM »
No, have a new, brass, plug on hand first.  I got one with a petcock for draining and anode rod too.
-- Ned -- Fulltimer 1997-2013
1997 Holiday Rambler Endeavor LE
2007 GMC Canyon

Ron

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Re: Hot water overflow
« Reply #47 on: March 14, 2005, 10:06:26 PM »
No, have a new, brass, plug on hand first.  I got one with a petcock for draining and anode rod too.

I remove the  the plug to flush the tank.  I don't see how the tank can be flushed though a petcock.  I do keep a spare nylon plug on hand.  and have replace one once just because I figured it was time.  However I still have the old plug on board somewhere to just in case. ;)
Ron & Sam-home is where we park it. Currently located   HERE

Karl

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Re: Hot water overflow
« Reply #48 on: March 15, 2005, 12:49:07 AM »
Quote
I remove the  the plug to flush the tank.  I don't see how the tank can be flushed though a petcock.  I do keep a spare nylon plug on hand.  and have replace one once just because I figured it was time.  However I still have the old plug on board somewhere to just in case.
I totally agree with Ned. Get a brass petcock w/anode. You can use the petcock to renew the "head" by opening it and the pressure relief valve to suck some air in, or remove it completely for flushing. Don't forget your teflon tape. I would also recommend you find that old nylon plug and toss it.
Karl (Cheesehead) Kolbus   Life's journey is not to arrive at the grave safely in a well preserved body, but rather to skid in sideways, totally worn out, shouting "...holy cow ...what a ride!"

 

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