Hot Water Heater Leaking from pressure relief valve

[ClydesdaleKevin]

Hey guys.  I did a message search, and couldn't find this topic addressed.

Yesterday our neighbor noticed water leaking badly from our water heater door.  So I opened it, and once the water heater gets up to near top temperature, hot water starts to pour out of the red painted pressure relief valve.

Now, this is the original water heat in the rig.  Still works great, and its peizoelectric.  Its the motor aid type, an atwood, and we love it.

The pressure relief valve also has a whole bunch of crystaline buildup all around the opening. 

Do you think the valve is bad?  I'm hoping that is all it is!  There doesn't seem to be any way to adjust the temperature on this model. 

If its the valve, does anyone know where I can get a replacement?  We aren't anywhere near an RV dealer down here in Eminence, KY.  Will a standard water heater pressure relief valve work, or is this an Atwood and/or RV specific part?

Thanks guys!

Kev

[DaveVA78Chieftain]

RV water heater uses a 1/2" pipe thread.  If memory serves me home units use 3/4".
RV unit is set at higher temp due to size.

http://www.adventurerv.net/water-heater-temperature-and-pressure-relief-valve-p-1177.html

[ClydesdaleKevin]

Adventure RV must be having website problems...can't get on at all.

So its an RV specific part is what you are saying, which means its going to be bloody expensive when I can find one...lol.

Kev

[DaveVA78Chieftain]

Not expensive at all.  That adventure net link says normal price $21.09, current sale price is $12.99.  Add a small amount of shipping and your done.

EBAY Listings: http://www.ebay.com/sch/i.html?_trksid=p3984.m570.l1313&_nkw=atwood+water+heater+pressure+relief+valve&_sacat=0

Biggest hassel with them is getting a wrench on it to remove/install it.  May have to remove other parts of heater to access it.

Dave

[Elandan2]

Or try your local hardware store.  I have always been able to find the correct ones there.  Rick

[JDxeper]

Another source
http://www.amazon.com/s/ref=nb_sb_ss_i_0_22?url=search-alias%3Daps&field-keywords=atwood+pressure+relief+valve&sprefix=Atwood+pressure+relief%2Caps%2C769

[ClydesdaleKevin]

Thanks guys!  When I'm out and about today, I'll keep on the lookout for one...although I've never seen an RV dealer anywhere around here.  If I can't find one, I'll order a new one tonight.

Kev

[DaveVA78Chieftain]

Posible source for heater valve
Guist Creek Marina
11990 Boat Dock Rd, Shelbyville, KY 40065
(502) 647-5359

On Guist Creek Lake

Dave

[ClydesdaleKevin]

So I went ahead and ordered one from Ebay, since I have a substantial amount sitting in my Paypal account.  Came out to around 20 bucks with the shipping...sweet!  I sprayed the old one around the threads with PBBlaster and am going to let it sit until the new one gets here.  It looks like the old one will be easy to remove...I can stick a breaker bar right down its opening to turn it.  I'll of course have to be more careful installing the new one.

By the way, water heaters made prior to 2003 use 1/2 pipe threads...newer models use 3/4 pipe threads...at least with Atwood water heaters.  Fortunately mine was a no brainer...still has a metal tag on it that says 1/2 inch with all the specs.

Kev

[ClydesdaleKevin]

So I replaced the pressure relief valve and drained the water heater tank and refilled it...then dried all the connections with my wife's blow dryer...and fired it up.  It turned right on...and then as soon as it got hot, it started leaking from the NEW valve and the water extinguished the flame again...

I called Atwood directly and got some good news...according to their techs, if it is lighting and firing up, the circuit board is good...which is the good news, since that part is over 120 bucks! 

They were VERY helpful and supportive over the phone.  They said it could be one of 2 things.  Either there is so much scale and crusty stuff built up in the thank that it is shielding the thermostat from getting a true reading of the temperature, or the thermostat is bad.  They recommended filling the tank with 3 gallons of white vinegar and 2 gallons of water and leaving it for 24 hours, then draining it out...which will remove all the scale.

So just in case, and since they are cheap parts, I ordered the thermostats...there are 2 side by side on this unit.  When we take a day trip to Indiana next week, I'll do the vinegar thing, and then replace the thermostats the next day.

I also ordered an anode rod to help keep the scale from coming back.

I'll let y'all know how it works out!

Kev

[DaveVA78Chieftain]

Anode rod for an Atwood?  Because of the inner cladded construction they do not use them. Did Atwood suggest this?
http://rialtainfo.com/thebaldy/winnebago/winnebago_images/water_heater_care_and_maintenance.pdf

Dave

[ClydesdaleKevin]

Nope Dave, that was my idea...its an aftermarket anode rod that replaces the drain plug on the Atwood.  I figure if Atwood said I more than likely have significant scale buildup in the water heater, then if I'm going to flush it out with vinegar, it won't hurt anything to use said anode rod, and might just help keep the sediment and scale from returning.

Kev

[DaveVA78Chieftain]

Once you get things back together, get a meat thermometer and draw some hot water out of the tank to see what the temperature is.  This may be an issue where the heat is not being transfered correctly through the tank to the thermostat so that it has to get hotter than it is supposed to to open the thermostat.  Thats what the scale build up would cause.

Dave

[salplmb]

a anode rod for your heater would be kind of wierd. they are a sacraficial part usually for a glass lined steel tank. like in your house (i know u full time ). i thought most rv heaters where made of aluminum so they dont need one. i am a plumber by trade and have seen many a anode rod melt away and turn into some wierd jelly like substance that clogges up faucets and fixtures. changing the thermostats sounds like the right fix for u. check to see that if u let off presaure dose the drip stop even though its hot? this could mean that there is a preasure problem. thermal expansion can sometimes cause this to happen in a closed loop system. good luck.
hope this helps a little.
sal

[TommyM]

I agree with the above about not needing an anode rod.  An anode rod is intended to sacrificially corrode away, preventing a steel tank from corroding.  It will do nothing for a scale problem, which is a build-up of minerals from the water.

If you have a petcock drain valve, you should probably remove it (rather than open it) when you drain your vinegar solution, and then flush with a ton of water to get all the scale that breaks loose out.

Tommy

[ClydesdaleKevin]

Well, I can't return the anode rod...lol...so its going in, since it won't hurt anything. 

Still waiting for the thermostat to come in, which probably won't be here until Thursday, so I'll do the vinegar thing in Wednesday morning and flush the tank out thoroughly with a garden hose on Thursday morning.

Hopefully this will fix the problem completely.

Kev

[ClydesdaleKevin]

So early this afternoon, I turned off the water to the coach, drained the water heater tank, reinstalled the drain plug, removed the pressure valve, and using a new funnel, I poured in the 3 gallons of white vinegar.  Then I tried to pour in the 2 gallons of water, but low and behold, only a half gallon would fit!  Hmmmmm...the pressure valve is near the top of the tank, but not AT the top of the tank, so that explains it, unless there is a LOT of sediment in my hot water tank from 1989 to present day!  I had a solution, so I reinstalled the pressure valve.

The Solution was to fill the tank the way it would fill anytime you drain it.  I turned the water back on, turned the kitchen sink faucet on hot all the way, and let the air purge from the tank, which didn't take long.  Okay, tank filled.  Water off.  Cold water turned on at the bathroom sink to depressurize the system.  Done.

Tomorrow I'll go ahead, around noon, and dump out the water tank.  Leaving out the drain plug, I'll remove the pressure valve again and purge the system with a garden hose until the water runs clean.  I have a hose nozzle that is cone shaped that will fit right in the opening where the pressure valve goes.

Then later in the afternoon, when everything is dry, I'll install the new thermostat and ECO switch which arrived today, the new drain plug with the anode built in, using teflon tape on the threads of course, and fire it up.

Hopefully that will be it, and my hot water heater will work like new again!

Kev

[ClydesdaleKevin]

Oh yeah, we also bought 10 gallons of drinking water, in gallon jugs, so we could rinse dishes, brush teeth, flush the john, etc...since the water is turned off until tomorrow afternoon.

Kev

[ClydesdaleKevin]

BINGO!  All fixed!

When I drained out the vinegar, it was white like skim milk with all the dissolved solids...and then when I stuck a garden hose in the opening where the pressure relief valve goes, a whole lot of chucks of white crystals came out...and I had to use a LOT of water to flush it until it ran clear and nothing but water was coming out.

When all was said and done with the flushing process, I installed the new anode drain plug with teflon tape, reinstalled the new pressure relief valve with teflon tape, and then set up a blower fan in front of the open heater door to dry everything out while I worked on another project.

A couple hours later, it was dry enough to install the new ECO and thermostat switches, which was very easy to do.  It had to be dry though, since there is a foam overlay that protects the switches that is self adhesive and sticks over the whole shebang.  A new one comes with the thermostat and ECO switches.  I also had to reglue the gasket over the propane pipe inlet and the gasket around the drain plug with rubber cement, since they came off during the flushing process.

Now it was ready to test.  Water hooked back up to rig and turned on, air purged and hot water tank filled by turning on the hot water at the kitchen sink, switch turned on.

It fired right up!

It shut itself off prematurely 3 times, with the red light coming on in the RV...but the 4th time it stayed lit all the way up to temperature, shut down with no leaks, and the green light stayed on, meaning all was well.

Then we went to dinner and a movie, so I shut it off while we were away, to make sure it would fire right back up.

It did!  And stayed on all night, and cycled normally this morning.

My guess is that there were still some wet connections in there during the preliminary start-up...and everything dried out completely as the heater reached full temperature.

So its fixed!  No leaks, cycling normally...SWEET!

Kev

[burt6666]

Glad to hear !!!!