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Metalguy Member Posts: 6
I have a 3-zone, gas fired, hot water system with 3 Honeywell Rheostats (2 for floor-1 and 1 for floor-2) that were installed way back in 1979. I could be wrong, but I think one of the three has gone bad, whenever the Thermostat in that zone calls for heat it's Rheostat takes much longer than the other two zones ever seem to take, and it would also go through a bunch of "clicking" before it would either turn on and send heat, or shut down and do nothing for a few minutes before starting the clicking over and over again. I looked very closely and watched it and I can see that it appeared as if something between the servo and the pipe tries to engage but doesn't or can't. So than I went and read some stuff about Rheo's online and on here and than went and switched it over to it's "Manual" setting, which didn't go too easily, I had to really force the little switch on the bottom over to the left and now cant switch it back to the right, but now I can get heat in the zone controlled by the bad Rheo., but it seems that it ignores the thermostat and sends heat when it wants to, not when the thermo calls for it, so it obviously needs to be replaced. I started Google searching for a new one and found that there are a few hundred different Honeywell's that look just like mine but, all have completely different numbers. Mine seem to have no discernible model number(s) to go by other than a few on the servo, so what should I look for in a replacement, or does it matter and anyone would work fine?
"I'm NOT a "Pro", I just know how to and prefer to use my own two hands and some tools to repair or replace what's broke when it's broke!"


  • icesailor
    icesailor Member Posts: 7,265
    Post photo's of the "Rheo's" and "Servo's here.
  • Tim McElwain
    Tim McElwain Member Posts: 4,506
    You are talking about Honeywell Zone valves not Rheos or Servos. Check for 24 volts to the zone valves if you have 24 and they are not opening then either the head is bad or the valve itself is stuck. Look in the cover there should be some numbers and also a CV rating so that will get you the correct valve.

    From the sound of the stuck manual operator the entire valve needs replaced, it is important to get the correct one as they pass different gallons per minute (that is what the CV rating is about). If you call a professional they will be able to solve your problem. Since 1979 says you have gotten your moneys worth.