Honeywell AM-1 Mixing Valve - Not Turning?

dhealey

Hi all,

This is probably me being a dummy. There is a Honeywell AM-1 thermostatic mixing valve on my Burnham V8H boiler. I tried to slightly increase the temperature for my hot water. I unscrewed the valve turned the dial slightly but nothing seemed to move, I felt total resistance. However, I must have done something because now the water gets too hot, but the temperature gauge still reads 170°.

How do I calibrate the temperature and should I feel the valve turning?

Intplm.

Seems like its bound up tight.
If it has unions you will need to take it apart/disconnect it. Have a AM-1 repair kit ready.
If its too bound up to repair due to corrosion or some other unforeseen damage, have replacements in hand before you start.

Lastly. Try taking the adjustment handle off entirely and turn it with a wrench. That might free up the valve.

hot_rod

There is sometimes a stop to lock the knob from being adjusted to hot. Under the cap is the locking/ limit tab.

How old is it, sometimes a rebuild kit works. But if the inside of the body is damaged or limescaled the rebuild kit may not work.
I’d replace the entire valve.