Atwood hot-water heater mixing valve

[fishon]

Hi, I’ve been visiting this forum for several years and it’s been a wealth of information. I bought my Excel used over a year ago and have not had hot water over 100 degrees since I’ve had it. Not hot enough for showers or doing dishes. The problem was the mixing valve. $260. Plus labor at the dealership. Atwood has tried to make the valve tamper proof. The mixing valve is on the back of the water heater and mine has a red knob. I had to remove the valve because I did not know they had put glue inside the screw hole where the torch bit went. That’s the tamper proof part of it. I think I could have done the job without removing the valve if I had known this. After the knob has been removed its very self- explanatory. You will see two sets of spines. The small one is to adjust the temperature and the larger one is to lock the knob to prevent it from being adjusted. Since I had to remove the valve I also had to remove two lines. When I put them back on I had leaks. The washers were bad. So be prepared for that. Went to the hardware store and bought some plugs for the bypass line for a temporary fix. When I came back home I went to HD and bought two 1/2 “by 12” flexible faucet hoses to be replaced when I go back to the camper next week. It’s nice to have hot water again. BE CARE. YOU WILL NEED TO MAKE SEVERAL AJUSTMENTS to get the temperature where you want it. When I go back next week I’ll follow up with a post with what size torch bit size you will need. Thanks for a great forum.

[Jim Stewart]

Great post, several Members have had similar problems with the Atwood heater that mixes ambient temperature water with the hot water from the Atwood to increase total hot water capacity. This may help several Members understand the problem.

Thanks for the thread!

[BookIIRoadtrash]

fishon, First I'd like to give you a warm welcome to the Excel Forum and then congratulate you on your Excel. I find your thread and first post here very interesting, you have done some research or had knowledge about this temperature control. Please keep us update on your findings and fix for this.

[rockintom]

Thanks fishon for the info. This is a age old problem with GXT Atwood WH. That said, we had one for 5 years and never had a problem with it. We also use a water softener and I service/flush the tank every 2-3 months. We FT, so we never did a winterization on our rig. Many WH folks complain of mix valve issues shorty after winterizing. I believe the issues stems mainly from calcium build up. Just my .02 worth. Oh BTW, the mixing valves on '05 model have 2 hoses connecting, and '06 and newer only have one hose. I think the later valve hooks up to the earlier model with a modification kit. rockin'

[pcurt23]

Yes the glue in the screw hole is a nice touch. I was able to get the glue out and turn the screw with an allen wrench. I'm not sure that I could have cleared the valve by opening up the valve all the way. I will try that method if it plugs up again. I think that the mixing valve should be the first thing to check when the hot water goes away.

The orifice was completely blocked with debris. I am not sure if it came from the water system of from stuff left over in the water system that finally broke loose. I do have a filter system.

[rockintom]

Pcurt23,
As I had mention previously in this thread, I used a water softener on our old '05 rig with the GE16EXT....went almost 5 years FTing and I serviced (flushed) the WH about about every 2 months. No problems all the way up to trade in last Dec. I believe that's why I didn't have any problems.....just my .02 worth. Thanks for the update on your unit. rockin'

[Tom SKP]

Quote:

Originally Posted by pcurt23 Yes the glue in the screw hole is a nice touch. I was able to get the glue out and turn the screw with an allen wrench. I'm not sure that I could have cleared the valve by opening up the valve all the way. I will try that method if it plugs up again. I think that the mixing valve should be the first thing to check when the hot water goes away...

OK, add me too!!! After my first winter of storage (with RV antifreeze in mixing valve etc and HW tank flushed) for our first 3 nights of this years camper usage, the mixing valve worked great. So I figured I was over the hump! WRONG!!!
Night 4 we had the 'luke warm shower' too. We had to check out of our CG the next morning, so learning from all of you....
I could not get all the glue out of the screw hole, so I got out my drill and drilled into the end of the screw and gradually increasing drill sizes, until I drilled off the screw cap head. Now the red plastic cap pulled off. I then turned the mixing valve open a couple of turns and the water finally got hot. I backed it off until the temperature was what wife said was safe and we moved on down the road.
Now almost a week later it is still working OK. Thanks for all the forum advice!!! And this drilling technique might help the next guy.

I guess the next question is what to do next? I'm still under warrantee for the next 11 months but I've got it working and probably can free it up by playing with the adjustment if it blocks up again. Or should I have it replaced and probably revisit this next year or so???

[rockintom]

Thanks Tom for the update.

Does any one hear me say WATER SOFTENER?????

[Still Working "NOT"]

Quote:

Originally Posted by rockintom Thanks Tom for the update. Does any one hear me say WATER SOFTENER?????

Ok SKIA, do you think the Water Softener helps more then flushing the Hot Water Tank every month or so, actually helped you not have problems with the mixing valve??

My thoughts are cleaning the water tank is the reason. I have a water softner in the house and I end up with lime/salt buildup in the faucets and have to clean them every so often. When ever I flush the hot water heater I break loose lots of deposit from the tank, with some ending up inthe water lines unless I flush the tank for 10 minutes or more. If I only flush the tank for a few minutes I seem to have more of a problem with the faucets.

[rockintom]

Quote:

Originally Posted by Still Working "NOT" Ok SKIA, do you think the Water Softener helps more then flushing the Hot Water Tank every month or so, actually helped you not have problems with the mixing valve?? My thoughts are cleaning the water tank is the reason. I have a water softner in the house and I end up with lime/salt buildup in the faucets and have to clean them every so often. When ever I flush the hot water heater I break loose lots of deposit from the tank, with some ending up inthe water lines unless I flush the tank for 10 minutes or more. If I only flush the tank for a few minutes I seem to have more of a problem with the faucets.

I don't know for sure Still. When I flush my WH the deposits are soft, white and slimmy. The mineral deposits never seem to crystalize.... maybe they never get hard enough to stop up the orifice in the mixing valve. Just my guess. rockin'

[davydee]

Quote:

Originally Posted by Tom SKP OK, add me too!!! After my first winter of storage (with RV antifreeze in mixing valve etc and HW tank flushed) for our first 3 nights of this years camper usage, the mixing valve worked great. So I figured I was over the hump! WRONG!!! Night 4 we had the 'luke warm shower' too. We had to check out of our CG the next morning, so learning from all of you.... I could not get all the glue out of the screw hole, so I got out my drill and drilled into the end of the screw and gradually increasing drill sizes, until I drilled off the screw cap head. Now the red plastic cap pulled off. I then turned the mixing valve open a couple of turns and the water finally got hot. I backed it off until the temperature was what wife said was safe and we moved on down the road. Now almost a week later it is still working OK. Thanks for all the forum advice!!! And this drilling technique might help the next guy. I guess the next question is what to do next? I'm still under warrantee for the next 11 months but I've got it working and probably can free it up by playing with the adjustment if it blocks up again. Or should I have it replaced and probably revisit this next year or so???

Tom & Rockin', would you all post a picture of the valve in your units? We've got the same issue, but I'm not confident where that value is located or what I'm looking at. Besides, the mixing valves are on back order (wonder why ). David

[davydee]

Quote:

Originally Posted by Tom SKP I guess the next question is what to do next? I'm still under warrantee for the next 11 months but I've got it working and probably can free it up by playing with the adjustment if it blocks up again. Or should I have it replaced and probably revisit this next year or so???

At least call SC and get a new one (when they come in) sent it to you as a backup. David

[rockintom]

Quote:

Originally Posted by davydee Tom & Rockin', would you all post a picture of the valve in your units? We've got the same issue, but I'm not confident where that value is located or what I'm looking at. Besides, the mixing valves are on back order (wonder why ). David

This is what it looks like in my 2010 33RSO. They are all located differently in each floorplan. From very easy to get to all the way up to you have to remove and replace the WH assy. to gain access. Even if you have to R&R it....it's not that bad a job. Just annoying that it has to be done. Make sure you have some new rubber seals for the hose ends....they tend to leak after replacing the mixing valve. Oh did I mention.....water softener (ala Virg) HTHs rockin'

[JerseyShore]

Got bit for $200 and had to change this on my unit when opening up this year. I changed it over this past weekend and it worked but didn't find this forum until today. At least I'm not the only one who has had this problem!

I was concerned that I did not winterize properly. I am thinking at the end of this season I may remove the whole thing.

Below is a picture of my setup. Thanks to everyone here for the terrific information.

Old valve


Installed