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One zone isn’t heating

LostHVACTech
LostHVACTech Member Posts: 6
in Thermostats and Controls

Recently changed thermostats and the zones were working fine before that and now one zone(family room) isn’t getting hot. It will turn on, run for a few minutes and turn off and it isn’t even close to reaching temperature
everything was working perfectly until this thermostat was changed and it’s just a 2 wire only for heat

It’s a 4 zone boiler

1-hot water

2- family room

3- basement

4-addition

All zones are on circ pumps

If pictures are needed will get them tomorrow

Comments

  • SuperTech
    SuperTech Member Posts: 2,382

    What kind of the thermostat is the new one and why was it replaced?

  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 16,283

    Sounds like the stat isn't set up right. Sounds like the old thermostats with the heat anticipator messed up but I am sure the new one doesn't have that. Cycles/hour or something is out of wack.

  • LostHVACTech
    LostHVACTech Member Posts: 6
    https://forum.heatinghelp.com/discussion/comment/1819790#Comment_1819790

    so it’s a Honeywell round with only r,w,y

    The one replaced was a Honeywell single stage non programmable

    They were replaced because they were “old” but they worked just fine

  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 9,157
    edited November 13

    Do you have Taco 570 series zone valves? The heat anticipator on the new thermostat may be set wrong.

    OR

    you have a thermostat that does not like the fact the the Taco normal operation actually cuts the circuit many times during the call for heat cycle. The is built into the valve actuator so the wax element that heats up and expands in the piston that pushed the valve open does no over heat and burst the seal leaving that actuator useless. The 570 series (3 wire heat motor) valve has a heater that causes a wax to expand when it heats up and pushes a piston down to open the valve. That piston also opens a set of contacts so the wax won't over heat and damage the valve. Sone thermostats see that open circuit as an error that causes them to reset and start over. It is all explained in this comment :

    https://forum.heatinghelp.com/discussion/comment/1785090#Comment_1785090

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • LostHVACTech
    LostHVACTech Member Posts: 6
    https://forum.heatinghelp.com/discussion/comment/1819791#Comment_1819791

    so it’s the base dumbest thermostat anyone could have it’s like the old school round ones where you can’t program it. I checked the wires and its getting voltage and it’s all wired right. It’s driving me mental on why it turns on runs and turned off after 1 minute

  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 9,157

    Base Dumbest thermostat is the model number? I'm not familiar with that one. Perhaps a picture of the thermostat on the wall and a picture of the wires connected to the base.

    Never mind, I googled "Base Dumbest thermostat" this is what came up. This is the model T822 and it DOES have a heat anticipator that needs to be adjusted to match your system.

    Screenshot 2024-11-12 at 10.12.27 PM.png

    If this is not the one you have than perhaps you can tell which model number of the Base Dumbest thermostat brand name you actually have.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • LostHVACTech
    LostHVACTech Member Posts: 6
    https://forum.heatinghelp.com/discussion/comment/1819807#Comment_1819807
    IMG_3352.jpeg
    Round Non-Programmable Thermostat with 1H Single Stage Heating

  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 9,157
    edited November 13

    That is a digital thermostat with an analog cover. It is made to look like the old analog T87F 1028. "Retro"

    If you have the heating only model it would be the T87K with three wires R, W, & Y. Y is used for some zone valves that need to have power to close. You probably have only R and W connected.

    I still need the answer to this question. What is the thermostat connected to? the heater directly? A zone valve? A multi zone relay? A thermostat alone does not a heating circuit make.*

    If it is a Zone Valve… What kind of zone valve is it?

    if you have one of these zone valves, then you may need to add a resistor.

    Screenshot 2024-11-12 at 11.30.12 PM.png

    * Old English quote from Shakespeare's book on old heating systems

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • HVACNUT
    HVACNUT Member Posts: 6,238
    edited November 13

    Have you tried reversing R and W?

    They are power stealing thermostats. It needs 24 volts at R.

  • LostHVACTech
    LostHVACTech Member Posts: 6
    https://forum.heatinghelp.com/discussion/comment/1819831#Comment_1819831

    I will try this

  • LostHVACTech
    LostHVACTech Member Posts: 6

    it’s connected to a taco zone Board and all the zones are on circ pumps

    EdTheHeaterMan

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