troubleshooting a mixing valve

CC.Rob

Thanks Ken. But this thing is only about 3 weeks old. Worked fine for a couple weeks. Had a burp, now appears to be (mostly) back to its old self. Water quality here is quite good. No lime issues even with fixtures 25+ yr old. Wondering if it could be funk/junk from installation that have now cleared, or whatever. Thoughts?

CC.Rob

troubleshooting a mixing valve

I have a sparco/honeywell AM101C tempering valve on my DHW supply. Been working fine until the other day we started getting tap temps noticeably below the set temp, but not awful. The indirect seems to be fine (i.e., this does not appear to be a problem on the tank side). I turned the mixing valve's adjustment knob all the way down and back a couple times. That or something else appears to have fixed it, at least 96% of the way (need to put a temp probe on the taps to be sure).

Question: do these valves ever get a piece of junk in them, or get stuck, or whatever? Other things to check?

Thanks.

Ken_40

You're already \"hip.\"

The problem is what you suspect. The cold and hot mix-points are prone to "liming" up. That "lime" is from water hardness and it "collects" when heated to a certain point. That "point" is typically in the mixing/tempering valve.

I urge you to try and carefully remove the "guts" of the mixing valve and clean it in white vinegar with a toothbrush. If it is limed up, you can bring it back to life. However, the little seal inside may be compromised and the entire assemply may be so bad as to justify a replacement of at least the guts, and maybe the entire assembly!

Do a web search for the guts-only replacement parts (better yet, call the nearest plumbing supply place) and have a source ready, should your inspection and vinegar cleaning go bad and the thing be too far gone.

If your not inclined to mess with it, a plumber could and would probably replace the whole thing for a few hundred ($200-300), assuming you can provide the exact make, model and pipe size(s) of the three connecting points.

Let us know how it pans out. Got a digital camera? If you take it apart, send us a before and after picture.

Robert O'Brien

Sparcomix

Rob

replacement kit is AM-1-020 RP for the 80-120 degree model. If you have a fax, I'd be glad to send you a copy of the literature. I'm using the same valve here. The sheets give cleaning instructions and show how to open it up.

Pete

hr

solder flux

or stings of teflon tape can gum them up. They are very easy to disassemble and clean. The service directions should have been with the valve.

Also if the indirect temperature has dropped, so will the output of the valve. Again the directions show the output temperature at various tank temperatures.

hot rod

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

hr

solder flux

or stings of teflon tape can gum them up. They are very easy to disassemble and clean. The service directions should have been with the valve.

Also if the indirect temperature has dropped, so will the output of the valve. Again the directions show the output temperature at various tank temperatures.

hot rod

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Maine Doug_51

In mine

one of the little rubber flappers (checks?) was distorted, perhaps from water hammer. Worked again after disassembly and tweaking (technical term).

Unknown

oh man...

Hope I don't have anyplms with mine installion of 4 of those 3 way valves on heating system... Since its on heating and no make up water...

Abracadabra

cevhh,

You might want to start a new thread instead of reviving an 8 year old thread.

icesailor

The closer the tank temperature is to the setting of the mixer valve, the worse the tempering valve works.

If the tank temperature is set at 120 degrees, and the tempering valve is trying to deliver 120 degree water, how much hot water is needed to overcome the required amount that is needed to make the valve operate?

It can't. You need a large differential for these valves to work properly.

hot_rod

As Ice mentioned you need at least a 25° difference between hot in and mixed temperature for thermostatic valves to work accurately.

You also need to watch the pressure, not to exceed 2-1 ratio between hot and cold side. This can become unbalanced when you start pumping thru a valve, especially with a high head circ.

And a minimum flow rate.

Usually if the valve fails or changes performance over time it is due to scale and binding in the mechanism.