Atwood Mixing Valve

[Too tall]

This is taking a interesting turn. PM (check), Inlet water filter (check), water softener no so much. I get it, softening water will greatly reduce if not eliminate scale in the mechs.



RM I went to school in St. Paul, MN. Yhis uptight fast talking eastern kid got a fast lesson in the peaceful art of getting along and telling a good story. Miss that place alot. PHC show was broadcast from my schools auditorium a number of times...powdered milk!

[JJTX]

Originally Posted by Too tall

This is taking a interesting turn. PM (check), Inlet water filter (check), water softener no so much. I get it, softening water will greatly reduce if not eliminate scale in the mechs.

If it stops the hard water and my time wasted for a warranty repair every couple of years, it's a cheap investment.

[dhroberts]

Agreed! And a positive response. I don't have a need to adjust today - good to know I have that option.

[RWKais]

Thanks for all the information. When I noticed a changed in my 23FB hot water I found the solution here. Hopefully the pictures illustrate how I had the exact same issue, and how I was able to use data found here to remedy the situation!!!!

[Cispook]

Anyone notice on replacement valve that the screen mesh is much smaller then on original ?

[JJTX]

No I never touched it after they installed it because it was a warranty repair.

[daboyce49]

Forgive my missing something but in a number of these photos one can see a diagram on the heater to the right of the mixer with two diagrams, one winterize and one not. The difference being what looks like something is either turned inline (non-winterized) or perpendicular (winterized). To what is the diagram referencing? The mixer valve has nothing on it to turn one way or the other as I can tell.

Thanks in advance for helping clear this up.

[Keith S]

Hi Everyone,
I was amazed at the "gunk" that came out of the mixing valve. In my case removing the valve was a real chore because the valve is in the back of the HW tank but difficult to access

I think that we should all be extremely vigilant about our water systems and keeping debris from accumulating. I am sure the previous owners did not have a water filter and neglected the system.

Going forward I suspect my system will foul up again and I will have to clean it.
I hope everyone has a Safe and Merry Christmas.
Regards,
Keith Stamper

[dbj216]

Seasons Greetings to you Keith: After reading this thread and following your "no hot water" thread I'm convinced I don't need a mixing valve. I like to mix it at the faucet instead. I understand RV hot water heaters are set scalding hot so we can have more hot water at the faucet by mixing it with cold. The mixing valve does this for us "automagically". If I was traveling with children, then the mixing valve would make sense. But not for old grandpas like me.

David

[Too tall]

Originally Posted by dbj216

Seasons Greetings to you Keith: After reading this thread and following your "no hot water" thread I'm convinced I don't need a mixing valve. I like to mix it at the faucet instead. I understand RV hot water heaters are set scalding hot so we can have more hot water at the faucet by mixing it with cold. The mixing valve does this for us "automagically". If I was traveling with children, then the mixing valve would make sense. But not for old grandpas like me.

David

David, on our first trailer that's what I did and nobody died which leads me to another day another mixing valve.


We have had this trailer two seasons and no issues until today. I've got obvious mixing valve "gunk" signals. Yes I've got a spare, we are AirstreamR's right?


What would be the problem if I remove that darn mesh screen which loves to collect mineral deposits? We did that on the first trailer and no issues.


I run a high quality two stage filter...for the record.



Tempting.

[brendakerry]

I have a 2015 25ft flying cloud FB. Is this valve Atwood part number 90029 universal?

[Daquenzer]

Originally Posted by brendakerry

I have a 2015 25ft flying cloud FB. Is this valve Atwood part number 90029 universal?

Before you change the valve have you tried cleaning it by soaking in white vinegar. But that's the one I use. I have a spare on hand just in case I don't have white vinegar.

[Daquenzer]

Originally Posted by Too tall

David, on our first trailer that's what I did and nobody died which leads me to another day another mixing valve.


We have had this trailer two seasons and no issues until today. I've got obvious mixing valve "gunk" signals. Yes I've got a spare, we are AirstreamR's right?


What would be the problem if I remove that darn mesh screen which loves to collect mineral deposits? We did that on the first trailer and no issues.


I run a high quality two stage filter...for the record.



Tempting.

Did you do that? I'd like to know how it went. I have to clean my screen just about every year. And I run a filter and a softener.

[brendakerry]

Thanks much. It must have been very corroded as after the soak there was still no much flow. I did replace and will is the old for a hot water emergency if neede.

[gwold]

Originally Posted by daboyce49

Forgive my missing something but in a number of these photos one can see a diagram on the heater to the right of the mixer with two diagrams, one winterize and one not. The difference being what looks like something is either turned inline (non-winterized) or perpendicular (winterized). To what is the diagram referencing? The mixer valve has nothing on it to turn one way or the other as I can tell.

Thanks in advance for helping clear this up.

daboyce49, I hope by now you've discovered the answer to your question, as it's been a while. But, just in case: The valve in the diagrams is that yellow one you see in the same picture(s). It's the bypass valve for the water heater. When in normal use, you want the valve open so the tank continually refills with use. When you're winterizing, however, you don't want your antifreeze to get into the heater's tank, so you close that valve (bypassing the water heater tank) first, before treating the lines with the anti-freeze. Of course, that also means you flush the lines in the spring, before your re-open that valve.

[ZOZ]

The Atwood mixing valve 90029 needs cleaning every year. Two guys on this forum suggested that and they are right. I cleaned mine last year and with slightly more than five weeks camping and with a Camco water filter (KDF/Carbon RV water filter) installed I still had luke warm water and the Atwood mixing valve was clogged with calcium again.

The valve is good; the filter backflow screen is the culprit.

Here is what I did: I removed the mixing valve but left the filtered screen part in the water tank by using the correct 1-1/16" open end wrench. Then I removed the brass end from the tank. The initial removal was with a propane tank assisted flame with a wet towel as security.

Here is the picture of the SOB part. With the backflow valve in my vise, I was able to use 0000 steel wool to get it cleaned then soaked it in CLR overnight. Blast it with compressed air on installation.

I have added this procedure to my maintenance log for service yearly.

zoz

[JJTX]

I use a GE water filter and a water softener now. I don't put hard water into my AS anymore. I had my valve fixed under warranty a while ago and immediately changed to a portable water softener.

No more calcium buildup. ( Plus the house style water filter to eliminate sediment )

[mbataillon]

Originally Posted by sheriff1

Just completed this project. Don’t order a new mixing valve yet!
Disconnect the cold water in and hot water out. Make sure pressure is released from system first. The silver portion will unscrew from the brass portion that is screwed into the tank. I used an old fashioned right angle adjustable wrench jut putting it on the body of the valve. That leaves the bronze portion into the tank, use a regular socket on that to remove, as I recall 1 1/8”socket. That’s where the problem is. This piece is the anti backflow valve and it has a screen on it that will be plugged with the white junk that forms in the tank. I had to clean mine a couple of times before I got rid of the white junk.

I'm having the same problem after winterizing my 2017 27FB last year. I was able to unscrew the valve by using a pipe wrench (counter clockwise) but am not able to unscrew the backflow valve, not comfortable with the amount of force I'm using and not sure if I need to unscrew this valve clockwise or counterclockwise. Help!!!

[Daquenzer]

Originally Posted by mbataillon

I'm having the same problem after winterizing my 2017 27FB last year. I was able to unscrew the valve by using a pipe wrench (counter clockwise) but am not able to unscrew the backflow valve, not comfortable with the amount of force I'm using and not sure if I need to unscrew this valve clockwise or counterclockwise. Help!!!

Righty tighty

Lefty loosy

It will take some muscle.

You can also take a compressor and blow the valve out from the top. The problem is that you will need to clean the sediment out of the tank then.

[Piggy Bank]

Following.
Had this trouble last weekend. It was our first trip out this year after de-winterizing in the spring. Tried to run the city water thru the hot water heater and that helped some. Will get the flush wand and try to better clean out at home in a week or so. And grabbing a spare mixing valve just in case.
Thank you to all who have posted!