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Room temperture Overshoots set temp

between the SR503 and the stats might be a factor here. There's more wire hetween the 2nd and 3rd floor stats and the SR503. This could be causing some voltage drop, which would raise the current slightly.

To verify, measure the current at each thermostat location.

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  • Domenic
    Domenic Member Posts: 5
    Thermostat problems?

    Hi, wondering if someone could point me in the right direction to troubleshoot this problem I'm having. I have a 3 zone hot water system, Burnham gas boiler,3 Taco 007 and SR503.
    Problem: First floor thermostat is set at 66 degrees, room temp gets to 72 and will not stop getting hotter until I dial back the thermostat. Other Zones work correctly except for one bedroom on the end of the 2nd floor loop is 4 degrees cooler than the rest of the floor. System has been bled. Any Help is appreciated.
  • Al Letellier_9
    Al Letellier_9 Member Posts: 929
    t stat problem

    You didn't mention what you have for stats, but I suspect an anticipator problem if you have the old style mercury bulb stats. If you have electronic stats, look at the flow checks. there may also be some piping issues.
    Did this problem just show up or has it been a problem right along? If it's a new problem, ask yourself what's changed in the system? If nothing has been changed, the problem is most likely the stat itself. If they are all the same, try swapping out tow of them. Just switch them and see if the problem follows the stat that's giving you trouble.

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  • brucewo1b
    brucewo1b Member Posts: 638

    Base plate on a mercury t-stat could be out of level also
  • Domenic
    Domenic Member Posts: 5

    Hi, thanks for the replies. The house was remodeled and the heating loops were repiped and a 3rd zone was added, boiler is 10 years old and was reused. It is half of a 2 family, 7 rooms over 3 floors, The thermostats are New Honeywell round Ct87a. The circulators are new, as well as the SR503. I changed the thermostat last night and the back plate is level, but the problem still exists. There is a 6-8 degree difference between set temp and room temp. My other zones work correctly, about a 2 degree swing in temp. I'm basically trying to figure out who to call(plumber or electrician) as I think I've done what I can, to troubleshoot this.

    Thanks for the help
  • Tundra
    Tundra Member Posts: 93

    Is it the new zone that is giving the problem? Did you install a check valve? Did you use the old check valves or did you replace them? Call the heating tech he should be able to help on both the electrical and plumbing diagnostics.
  • Domenic
    Domenic Member Posts: 5

    there are new check valves on the supply side. The plumber who did the work is coming out thursday, I was just trying to figure it out for myself but have hit a wall.

  • I would try to see when the ralay pulls in while you are adjusting the t-stat and view what exactly the temp is at that point. Are you over shooting due to some other heat source ie tv, lights, computer. You will need someone to help you while doing this. I am not familier with the boiler, does it have an internal primary pump? I have seen this problem with a Weil.
  • Domenic
    Domenic Member Posts: 5

    My question is what would cause the thermostat to keep calling for heat when it is 6-8 degrees past it's set temp. I have to dial the thermostat back 2 degrees to get it to stop. The house is well insulated and has newer windows. It gets way too hot on the first floor. I think the location of the thermostat is good, not near the front door or radiators.

    Thanks for the replies, keep them coming.
  • brucewo1b
    brucewo1b Member Posts: 638

    Check the anticipator setting is it over .2 best to check it out with a meter but the taco control calls for .18
  • Domenic
    Domenic Member Posts: 5

    Moving the Anticipator to .2 worked and now the room temp is more in line with the set temp.

    Here's what gets me, Honeywell suggests the anticipator be set at .8, the thermostat comes out of the package at .4. I have 3 of these thermostats on three different floors. 2nd and 3rd floor work fine with the anticipator left at .4.

    Am I overcompensating for a problem elswhere by adjusting the anticipator this low?

    This site is great, Thanks for the suggestions.

This discussion has been closed.