Revisiting the Atwood mixing valve issue

[Caffeinated]

So…Covid has upset a lot of plans over the last year and a half. But we finally got out in our trailer for a few days at the OR coast to escape the heat. And while there we experienenced the classic mixing valve problem, low flow on the hot water side and tepid water turning to cold.

Brought the trailer home and tried to take off the valve but for the life of me, I could not budge it. That sucker is on there tight.

While doing that I noticed the bypass was in the off/perpendicular position, and had the thought that that could be the whole problem. I know, I’m a genius. Not. Anyway,I reconnected my water lines, and now the hot water line has a little drip which I hope to fix with more Teflon tape.

But if the valve stills acts like it needs to be cleaned, why not drain all the water out of the system, and put in ten-twelve gallons of vinegar in the fresh water tank, cost less then ten bucks, pump it through the lines, sit over night and flush. Shoukd clean out the valve, yes? Lots easier than trying to get that @#$* valve off the tank.

What say the brain trust?

Mike

[Dennis C]

Did you try a plumber’s pipe wrench to remove the valve? I needed a 10” pipe wrench to remove mine.

Another option might be one of those cleaning “snakes” that attach to your hose and go into the hot water tank through the drain opening.

I think your vinegar idea sounds interesting, but it might be kind of a pain in the butt, and it may not remove larger pieces of debris. I had to use a Q-Tip on the screen of my valve when I cleaned it. This helped remove some of the larger, flaky particles.

[Caffeinated]

Unfortunately, I do not have the physical space under the sink in the bathroom where my hot water tank is to use a larger pipe wrench.

Mike

[GCinSC2]

Mike,

Don't have same, just curious. Got a pic of the situation?

Gary

[Caffeinated]

Originally Posted by GCinSC2

Mike,

Don't have same, just curious. Got a pic of the situation?

Gary

I don’t know how to post pics here. The situation with space is that the sink area butts up to a wall, that is part of the pantry. So I can only rotate the pipe wrench about a inch befotpre it runs into said wall.

But, I’ve fixed the leak on the hot water line, and now, with the bypass open, I have both good water pressure and hot water. So I’m good for now.

I’m still thinking it won’t hurt to run vinegar through the system to try and lengthen the time before I really do have to figure out how to remove the valve.

Mike

[SSquared]

I have done the vinegar thing once. In my case, my mixing valve was still working OK but I was hearing crackling noises from the water heater, and had other signs of calcium build-up. (I was getting water from a well in a limestone mountain). Based on something I saw on this forum, I used a 60/40 blend of vinegar and distilled water. I cycled the water heater with the mixture in it and let it soak for about twelve hours.

Afterwards, I flushed a bunch of chunks of calcium (calcite?) out of the water heater.

After rinsing out the vinegar, I got a water softener, and had no more trouble for the rest of my four month stay on the mountain.

[Oldtrapper]

I use a coffee machine descaler called Durgol to descale mine in place. I disconnect the adjacent plumbing and fill it will Durgol using a big syringe. Easy peasy and works for me.

Try putting some Durgol in a scaled up kettle or something and compare the reaction rate with vinegar.

[RamTruck]

Mike,

I have a 2020 27' Globetrotter. Our water systems are very likely to be the same. I had different symptoms causing my concern. I removed the mixing valve yesterday with 10" channel locks. It was very firmly secured.

Upon removal and inspection, I am convinced I need a new valve.

Please see the photos of what I found. I use a water softener that gets recharged at regular intervals. Seems that there's just still enough hardness in the water to foul the mixing valve. In my case, the cold water line was pressurizing after the water heater had come to temperature. I suspect the calcium buildup in the mixing valve is preventing the valve from fully closing and allows hot/pressurized water to return backwards in the cold water line. I solved this all by placing a check valve in the supply line to the water heater.

Also the 10$ hose attachment from Camco to rinse out the water heater tank is a valuable tool, if you don't already have it. Every 3 months I rinse and am continually surprised by all the junk that comes out.

I wish you well.

[Caffeinated]

Originally Posted by RamTruck

Mike,

I have a 2020 27' Globetrotter. Our water systems are very likely to be the same. I had different symptoms causing my concern. I removed the mixing valve yesterday with 10" channel locks. It was very firmly secured.

Upon removal and inspection, I am convinced I need a new valve.

Please see the photos of what I found. I use a water softener that gets recharged at regular intervals. Seems that there's just still enough hardness in the water to foul the mixing valve. In my case, the cold water line was pressurizing after the water heater had come to temperature. I suspect the calcium buildup in the mixing valve is preventing the valve from fully closing and allows hot/pressurized water to return backwards in the cold water line. I solved this all by placing a check valve in the supply line to the water heater.

Also the 10$ hose attachment from Camco to rinse out the water heater tank is a valuable tool, if you don't already have it. Every 3 months I rinse and am continually surprised by all the junk that comes out.

I wish you well.

Yikes! That is some serious scale. I guess I’ll try the channel locks when mine fails.

Question. Looking on Amazon for a replacement valve, Amazon describes it as for a ten gallon XT tank 90029. Is that the same valve that’s on my 6 gallon tank? Seems like it should be.

Mike

[RamTruck]

Mike,

For the removal, I made sure to put the teeth of the channel locks on the brass of the inlet, just below the silver housing. That brass has hex sides and should give you some nice grip.

I believe the 90029 is the one you want. It's the one I have.

When searching for parts my method is as follows:

- review included literature in the Airstream kit (for confirmation purposes, but sometimes includes more than one model)
- double check the equipment for a sticker (if accessible)
- review the Airstream parts manual for the airstream part number
- take the airstream part number and search at HighSkyRVParts.com
- if a hit, it should have the manufacturer's part number
- go to https://techsupport.pdxrvwholesale.com to find the appropriate manual and find the manufacturer's part number
- then source the part from where I can find it

Here's the link to the Atwood water heater manuals: https://techsupport.pdxrvwholesale.c...-water-heater/

[airmaine]

I clean the screen in my mixing valve each spring and I find bits of grit that will affect the flow. That can only be done if the valve is removed.