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No Heat to First Floor

KK_3 Member Posts: 3
We have hot water baseboard, 2 zone valves, 2 thermostats (1st flr, 2nd flr), Honeywell. Last week 1st flr heat stopped working. Forecasted to be cold in a couple of days, need to fix this. I think its the powerhead on the 1st floor zone valve but need to make sure before I buy one.

With the furnace warm, if I manually open the 1st flr zone valve we get heat to the 1st flr.

If the furnace is cold and the 2nd flr stat is NOT calling for heat, if I turn the 1st flr stat all the way up the furnace DOES NOT come on. I thought this might point to a bad stat but if I short the 1st flr stat wires the furnace still does not come on.

Thanks for any Help


  • Brad White_9
    Brad White_9 Member Posts: 2,440
    Some thoughts not specific to any valve type

    I would start at the thermostat. Cross the wires and see if that starts the process (valve open, boiler fires) you can eliminate the thermostate as a variable.

    Do both zone valves share the same relay? If separate relays, I would check the first floor relay as well.

    But because forcing the valve head open gets you flow, that helps narrow things down. I suspect as you do that the power head is gone and with it the end switches which fire the boiler. If you jumper the wires on the terminals going to the boiler, does the boiler fire? If it is the end-switch it is probably time to change the head anyway.

    My $0.02

    I am sure others have far better ideas.


  • aaarrrghhh!

    Please don't call your boiler a furance!
    Sounds like ur zone valve or thermostat ( did you change it recently?) or relay may be bad... If you need to call for service, ask for a BOILER pro and you'll get the right person for the job at first time...
  • KK_3
    KK_3 Member Posts: 3

    >>>>Please don't call your boiler a furance

    Sorry, won't happen again. I'm gonna replace the powerhead on the honeywell. I've never done this before so besides switching off the boiler and flipping the breaker any thing I should watch out for?
  • Big Ed
    Big Ed Member Posts: 1,117

    Raise the thermastat all the way up and check the voltage across the valves two yellow leads. You should have 24V , if not check wiring or thermostat.

    If you have 24V .... And if valve and end switch is good , On a Honeywell you can just change the motor .

    If you need a power head.... Work depends on either its a old or new style.. New would use two screws to hold down power head , old style uses Four . New style just remove and replace the head . Old style you need to drop the systems water and replace the guts as well to covert to New style.
  • william_5
    william_5 Member Posts: 62
    no heat one zone

    Before i start replacing things i open the wire to the bad power head and pig tail it to the good one ( note) not all zone vales are all 24 v some are 24v to power head 110 v to end switch . now with it pig tailed to the good zone rais the good therastat now does the vale open?? if yes look at therastat wireing, and or thermastat if vale opens and burner or circ does not come on that you have a bad end switch (replace v 8143 comp ) hope this helps
  • KK_3
    KK_3 Member Posts: 3

    I changed the power head, all is GOOD! Thanks to everyone for their comments.
  • Glenn Sossin_2
    Glenn Sossin_2 Member Posts: 592
    The right ending

    What we all strive to achieve
This discussion has been closed.