Atwood water heater leaking question

[mikf]

I have a 2002 Adventure 35u. Atwood gch10a-3e. We are are on a 3 month trip and noticed the floor in the compartment next to the water heater getting wet. Visual inspection of connections on back could not see any leak. Wrapped tissue paper around connections, still nothing. I put a wash rag at the bottom behind the heater and mopped all the water. Left rag there and again was soaked with water. If it is a pin hole in bottom I hope it doesn’t worse before we get home and I can remove heater to inspect the bottom. I am puzzled that when I wring the rag out it is always cold water, not even warm. Am I missing something that I can check without removing the heater? Does the electric heating element have a gasket or seal that could be leaking? But if it was leaking there it seems like the water I am mopping out would at least be warm. Thanks for any input as to what to look for without removing it until I get home. Also it doesn’t seem to make a difference if using the pump or shore water. When using the pump I never hear it cycle on when not running at faucet.

[Morich]

Just guessing but I might ask about the parts at the left side of the heater (as we look from outside!)
There are a lot of connections there and the little plastic filter on the water pump is pretty fragile.
Water gets tricky as it can come out one place and fall on something like another line and run to the spot we find it!
Maybe a close look there?


Also there appears to be a metal panel there with a couple angles screwed in to hold it? Any chance one could get that out for a better look under the heater?

[navnaz]

One year ago I had the same experience with the same model Atwood water heater. A mobile RV tech found a pin hole leak. Water was collecting in the bottom of the water heater compartment. It was replaced with a Dometic model similar to the old model but without the travel heater option. Works good, no leaking now

[mikf]

Originally Posted by Morich

Just guessing but I might ask about the parts at the left side of the heater (as we look from outside!)
There are a lot of connections there and the little plastic filter on the water pump is pretty fragile.
Water gets tricky as it can come out one place and fall on something like another line and run to the spot we find it!
Maybe a close look there?
Attachment 188342

Also there appears to be a metal panel there with a couple angles screwed in to hold it? Any chance one could get that out for a better look under the heater?
Attachment 188343

Thanks for the reply. I have wrapped paper towels at all of those places, including the water pump and clear filter on the pump. We just got back from breakfast and I checked all of the paper towels and nothing wet. That panel on the side is wood and I had that off a few years ago when I had trouble with the electric side not working, which turned out to be a broken wire, so I did not have to mess with the heating element. I cut a piece out of the panel at that time so that I could get a better view of the back. Also what am I missing on my signature? Or do I need something different on my avatar?

[mikf]

Unless the leak gets worse I do not want to remove and or replace the whole unit until I get home. I would want to clean that area under the tank and repaint it. The bottom looks to be rusty.

[Morich]

Signature looks good and complete from here.
It gives us all the info for looking at any of the online info as they are listed year first, then model like Adventurer and finally the floorplan (35U). Some will have an early and late year build but I don't see that for your RV.

It is just one way to cut straight to the chase if it is all posted on each post without having to remember to do it manually! Looks like you have it all covered.
Now the problem is still, "what's leaking?"

A thought on the leak might be that you have the "motoraid" if I remember right? That lets engine coolant run to the water heater to use engine heat.
No smell of antifreeze that might say leaking from that system? That might help to explain why no water pump cycling if it were engine coolant instead of fresh water?
Maybe engine running builds pressure which after parked for a bit, it is cool and may stop as the pressure bleeds off?

Not much help if you still can't see it! Maybe somethings as simple as a clamp getting loose but still a pain if you have to pull it all out to get to the clamp!!

[mikf]

Morich, I have a clear view of the motor aid hoses and it is not antifreeze, it is cold water. I think that I will try redoing the connections on the cold water side, but will wait for a week day incase I break something and have to go to the hardware store. Closest RV parts store is 50 mile. I misread your first post about my signature . I saw your signature and thought you was talking about mine. If I figure out how to attach a photo I will send a picture of the fittings. I am not sure if there are rubber O rings or some kind of seal in them. that is just a shadow on the paper towel

[Morich]

No biggie with the signature! Confusion is part of life!
Want something to make you laugh a bit while trying to figure it out?
Check this post of me trying to get the cover off the fuse box!
https://www.winnieowners.com/forums/...ck-353197.html

Something that make be more help? There are lots of parts on the plumbing that are standard issue hardware parts! So if there is a big box store closer, try them first.

You are a wise person not to mess with anything to do with plumbing until it's early in the day and every store is open. It seems to make it certain I will break something!

[Sierradave]

I have a 2006 33V Adventurer. I had a cold water intermittent leak coming from behind my Atwood heater. I was from a cracked fitting at the elbow near a check valve. I have a rubber-like inspection cover (about 4" x 8") underneath the backside of my heater and found the leak that way. I had to crawl under the rig to access it. It leaked when I had more than 40 psi pressure. I finally accessed the leak area by removing the adjacent metal divider panel (wall). This allowed me to get my hands behind the heater and replace the cracked fitting. Actually, I needed my son-in-law's hand to hold a wrench thru the inspection slot underneath the rig.

[Duner]

I would bet a dime to donuts that your leak is a pin hole in the bottom of the tank. My coach is a couple of years newer than yours and I had two pin holes in the bottom. Took it to a local weld shop and hit in two places with a heliarc, pressure tested it over night, picked up next day for $65. That was two years ago and no more leaks.

When I was pressure testing at home before I reinstalled it, what I noticed is that my cold water supply pressure was 65 psi. But after the tank heated up the pressure went up to 120 psi. So my advice to you is turn the heater off until you get home to slow down the leak. Heat water on the stove for cooking and washing. Temporally turn it on to take showers and turn back off.

Good luck,
Bill

[Morich]

Originally Posted by Duner

I would bet a dime to donuts that your leak is a pin hole in the bottom of the tank. My coach is a couple of years newer than yours and I had two pin holes in the bottom. Took it to a local weld shop and hit in two places with a heliarc, pressure tested it over night, picked up next day for $65. That was two years ago and no more leaks.

When I was pressure testing at home before I reinstalled it, what I noticed is that my cold water supply pressure was 65 psi. But after the tank heated up the pressure went up to 120 psi. So my advice to you is turn the heater off until you get home to slow down the leak. Heat water on the stove for cooking and washing. Temporally turn it on to take showers and turn back off.

Good luck,
Bill

This would not be something I would favor doing.
Most rv water regs hold the pressure down around 40PSI and if you are getting to 120PSI, you are really getting close to the pressure relief valve popping off to release the pressure.
The main concern I would have is that it is putting lots of pressure on things like compression fittings like shown in the picture above! Those fittings are only held together by the pressure of the rubber compressed onto the tubing and at 120PSI, I would think they are near blowing apart!
Have you tested the overpressure valve lately to be sure it is not stuck?

Maybe they stay together or maybe not but I don't like to go that close to the edge of a major water line blowout!

[Duner]

Originally Posted by Morich

This would not be something I would favor doing.
Most rv water regs hold the pressure down around 40PSI and if you are getting to 120PSI, you are really getting close to the pressure relief valve popping off to release the pressure.
The main concern I would have is that it is putting lots of pressure on things like compression fittings like shown in the picture above! Those fittings are only held together by the pressure of the rubber compressed onto the tubing and at 120PSI, I would think they are near blowing apart!
Have you tested the overpressure valve lately to be sure it is not stuck?

Maybe they stay together or maybe not but I don't like to go that close to the edge of a major water line blowout!

You don't have a choice on the pressure when it heats water in the tank. These Atwood's have a fixed temp setting I'm guessing around 120 maybe 125 degrees. The internal tank pressure probably varies some depending on how big the air pocket is in the tank above the water level. There is a check valve on the cold input, so that pressure is not going out into cold water side. I've never seen pressure in my coach anywhere close to 120. My coach came from the factory with water pump psi at 65 and that's what I set my city water pressure regulator to. If it got to 120 every time the water heater kicked on, you would know it right away from the spray intensity.

I've seen water heater over pressure valves weeping many times. Not just my WH, but many others. My educated guess is that the pressure builds up getting close to 150 psi, and then bleeds of the pressure to a safe level. Probably varies over time depending on how much calcium builds up at the valve.

When I measured 120 psi, the tank was out of the coach but close enough to connect the wiring. I had the outlet capped off, and a check valve on the inlet. It held the pressure overnight with no leaks. I was looking for any new "soft spots" that might start leaking. It looked like the erosion is just the bottom 6-8 inches and if a new leak popped up overnight I figured the tank was a goner. But it has held up for more than 2 yrs. I built up a plastic catch basin under the tank, so that if it leaks again, the water runs straight out he front and not down in the adjacent storage compartment (like OP's leak).

[Ray,IN]

All RV water heaters must have an air space in the top/ head space. Since water absorbs air, the head space disappears with time. To reestablish the head space, shut off water supply, open a faucet to relieve pressure, then open the over-temperature/ over-pressure valve lever, f When water stops running out allow the lever to snap back closed to seal properly.
Now close that faucet and turn on water supply. This eliminates the possibility of that valve leaking.
Winnebago has a habit of installing a check valve on both cold water inlet and hot water outlet fittings. If either sticks closed you have no hot water at faucets, so if you have hot water,, the check valves are OK.



Since the tank is aluminum it cannot corrode through, unless the interior coating/anodizing is compromised by an outside source.
Did you make sure the 120V heating element seat to tank is not leaking?

[DancinCampers]

There are cone washers located in the plastic fittings that attach to the brass check valves. They can deteriorate over time, especially the hot water out. I would try and snug that fitting to see if it is eliminated.
I have had pinhole leaks on my tanks, one under the Temp/pres safety valve fitting welded to the tank and one under the drain fitting attached to the tank. These would leak into the foam surrounding the tank. By the time it overflowed to the floor it was no longer hot.

[winnie32v]

Since the tank is aluminum it cannot corrode through, unless the interior coating/anodizing is compromised by an outside source.
Did you make sure the 120V heating element seat to tank is not leaking?[/QUOTE]

In my experience, Aluminum hot water tanks do coorrode......Both from the outside and inside.
The inside of an old hot water tank is normally very rough with signs of many corrosion pits. These corrosion sites are just waiting to break through to the outside creating a "pinhole" leak. These are easily seen by pressurizing the tank with 'city water' using the appropriate adapters. Many have had the pinhole 'patched' by a skilled aluminum welder, but at this stage of decomposition, there is a possibility of other pinholes occuring.

Also, new replacement hot water tanks do not incorporate the engine hot water heat exchanger to heat the tank water while driving.

[Dallasrules]

I have a 2011 winnebago Vista 36D. I have a similar leak. Water collects underneath. But I can't find any leaks from the fittings. We used the tank minimally at the end of season and now it is winterized. I am waiting until spring to investigate further.

Another weird thing is that the bypass valve doesn't seem to be working. No matter which way we turned it while winterizing, water or antifreeze still came out of the tank. It is possible that the valve is bad, but there is resistance when you turn it and usually if it is broken, it just turns freely.

I hadn't considered that it could be welded, but I may give it a try if it turns out to be a pinhole as I suspect.

[mikf]

I finally got around to removing my tank. Got some fittings and aired it up to 40psi and found a pin hole in the side right at the weld. the bottom was corroded and pitted pretty bad, so I am going to find a new tank. Thanks Morich and everyone for your help. Still don't understand why the water that I was mopping up behind the tank was cold (not even warm) when it was leaking out of a tank of hot water.