Aquastat problem?

nick z.

Customer has problem of water being to hot,W-mc. with coil. I find boiler temp. set over 200 deg. and no tempering valve. I add valve, and turn temp down to 180. She calls back in a couple weeks with the same problem. I find the boiler temp is around 200 on the gauge but Aqustat is still set at 180.I checked tempering valve and did not seem to be burnt out.I could not get upstairs to check water at the fuacets.
I'm asking could the Aqustat fail in such a way that it would turn the Burner on everytime there is a call for heat?Could the high limit fail? Thanks.Support our troops!

Rick Price

first

I would check the boiler tridicator gauge, I've seen enough of them lie. I have a woman who thinks her boiler water is set at 240 Degrees F, because its been pinned that way for 20 years. Just a thought before you replace an aquastat.

Unknown

Boiler override

We see that sometimes on new installs . The burner will turn off at 180 and the boiler will keep heating , sometimes past the 200 mark . What type of aquastat is it ? With a triple aquastat and a coil , we dont see it override often , because theres a call for heat when it goes to the higher setting , basically cooling things off in the boiler with return water . But with a 4081 and no call for heat , it could overshoot the setting . Oh yeah , we've been having a real bad run on boiler supplied gauges . I would change it just to be sure . Good luck .

Al Letellier

tempering vavle

We recycled plumbers are good for something.....maybe a stupid question, but did you properly trap the mixer? Did you use a flow restrictor? True the gauges are never accurate and I'd trust the aquastat before the gauge. Those great little thermometers we use on radiant work great on the discharge side of your mixing valve.
we don't put too many coils in these days, but we always install a guage on the mix side of the tempering valve. Makes trouble shooting and adjusting the temp a whole lot easier. Just open a hot tap and adjust away.
The boiler temp should have little to do with discharge temp of the mixing valve if it's installed properly and working correctly!!!!

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nick z.

Thanks for all the info. Yes, I did trap it properly. I'm going to check to make sure aquatat is shutting off on high limit when theres a call for heat. Thanks

ScottMP

I agree with Al

No matter what the boiler is hitting for a temp, ( and aguastates will over shoot ) the tempering valve should be mixing the water. What brand did you use ? Maybe something stuck in it after you left.

We install Sparco tempering valves. No more little tiny temering valves that get crusted up in a year.

Aquastatse can be off by 15 degress and boiler gauges just as bad. Between the two you can have a huge range of temp.

The only temperature you should be concerned is whats coming out of her faucet and that tempering valve is not doing it.

Scott

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