Open Roads Forum

Print  |  Close

Topic: Atwood Mixing Valve issues - New Hot Water Tank

Posted By: BobsYourUncle on 05/29/10 11:38am

I am set up in a park in BC's Okanogan Valley for a few days when one of my neighbors had his Atwood HWT fail.

He somehow managed to find an identical replacement in a nearby town and bought the unit. I pulled the old one and installed the new one for him.

I hope someone here knows a lot about the Atwood mixing valve.

Here is the problem:

The new unit has a mixing valve on the back of the tank. The box had been opened at the RV parts dealer and the valve had been played with by various people, turned in and out. We were told we would have to adjust it to get the mix right. No big deal.

I had to do a little plumbing to get the water lines in the right spot - no problem with that. I checked for leaks, everything was OK.

A couple hours later after the tank had heated up on its first load of water, we found water spraying out of the mixing valve, soaking everything in his basement compartment. He's not happy, I'm not happy because I did him a favor and installed the thing.

This is a brand new unit and there is water coming out of the mixing valve. Both of us have adjusted the valve to get his water at the correct temperature at the outlets. He had turned the bypass valve to stop the water flow to the tank. I reached in and turned the mixing valve back and forth with no pressure on the lines and it turned in and out easily. Then I turned the water back on and then turned the valve again. It was a lot harder to turn it in and out. I cranked it in and out, with water spewing out of the valve. When I turned it all the way in clockwise, the leak stopped. We have left it in this position so he can use his hot water. He is 750 miles from home and we need to correct this for the balance of his trip.

Can any of you with knowledge of these valves shed some light on the subject?

I cannot seem to find any info on the correct method of operating and adjusting these valves.

I am hoping I didn't mess up the valve somehow and that the leak is a factory defect.


2007 GMC 3500 dually ext. cab 4X4 LBZ
Duramax / Allison
Fire Red

1997 Triple E Topaz 27' Bunkhouse TT

81 Citation 25' "Tail dragger" "Under construction"

"Workin' man's rig"

Bob's Trucks


Check Out My Rebuild Project

Project Feedback



Posted By: Rob's on 05/29/10 09:46pm

This is the only instructions the traning manual gives us there are pictures I didn't include if your wondering.

1. Remove water lines (1), flexible hoses (2), mixing valve (3) and inlet plumbing components (4).
2. Install new mixing valve (5) with teflon tape. Use three wraps and pipe thread sealer to leading threads and install to minimum 35 fl/lbs.
3. Install male/male 90 degree fitting with a minimum of three wraps of teflon tape, stopping at approximately 1 o’clock on last turn.
4. Assemble tee to ball valve using a minimum of three wraps of teflon tape.
5. Install valve/tee assembly to elbow using a minimum of three wraps of teflon tape.
6. Finish turn on completed elbow/valve/tee assembly to horizontal position.
7. Adjust tee and valve so valve handle operates and tee is pointing branch thread upward.
8. Install flexible hose following instructions on hose tag.
9. Reconnect water lines. Apply Valve Position Sticker on back near valve.
10. Pressurize system to maximum 50 psi and check all connections for leaks with leak detecting solution.


Rob
RV Tech


Posted By: 1rooster on 05/30/10 06:29am

I am not familiar with the HWT model. I have an EXT model Atwood. I thought that the EXT models were the only one's with the mixing a valve. I have replaced 3 mixing valves on my '06 Discovery. The valve that I have only has 3 inputs and you can't adjust the the temp knob on top. If you want to see a picture of the valve I'm using send me a PM with an email address that I can attach a picture.


Posted By: BobsYourUncle on 05/30/10 10:05am

1rooster wrote:

I am not familiar with the HWT model.


Thanks,
HWT is an acronym for Hot Water Tank


Posted By: MPD56 on 05/30/10 10:22am

Bob: My mixing valve just stop working properly, I don’t know if Atwood installed it or Jayco. I guess I’ll find out Monday. All the mixing valves that I have seen have been set at the factory and the knob has a rivet holding it on so that you can’t adjust it. Behind the knob are locking teeth and if you force it, you break the knob. Haven’t had time to look the valve up, but it the dealer won’t fix it free, I think I’m going to remove it and hook up a regular by-pass system.

Good Luck!!


Posted By: BobsYourUncle on 05/30/10 12:39pm

MPD56 wrote:

Bob: My mixing valve just stop working properly, I don’t know if Atwood installed it or Jayco. I guess I’ll find out Monday. All the mixing valves that I have seen have been set at the factory and the knob has a rivet holding it on so that you can’t adjust it. Behind the knob are locking teeth and if you force it, you break the knob. Haven’t had time to look the valve up, but it the dealer won’t fix it free, I think I’m going to remove it and hook up a regular by-pass system.

Good Luck!!


This one here rotates freely and did so when the HWT was still in the box at the dealers parts dept. It appears that it had been played with by several others before we got it.

As for the bypass on yours, I suggest being careful there. I have learned that the water in the tank itself is set much hotter than normal and that the purpose of the mixing valve is to blend a little cold with it as it goes into the system so you can stretch a 10 gallon tank to 16.
If you introduce water that is too hot into the plastic lines, there is a greater risk of having leaks from something softening and coming apart under pressure.
If you do the bypass, I suggest changing the built in thermostat switch to a cooler one so the tank shuts off sooner and your water is at a usable temperature instead of way too hot.
I'm beginning to think we messed up the valve by turning it when the unit was under pressure but I cannot locate any info on the operation and adjustment of the valve.
I'm pulling out of the park tomorrow morning so he will be on his own to figure it out. I just want to make sure that it is serviceable for the trip home without dumping a ton of water in the storage bay area.


Posted By: BobsYourUncle on 05/30/10 12:41pm

Rob,
Thanks for the info from the training manual. I appreciate any and all info I can find.


Print  |  Close