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One Tstat will call for heat and circulator works but boiler does not come on

lrodptl Member Posts: 10
edited October 2018 in Gas Heating
I have a 3 zone baseboard heat system. Each zone has it's own thermostat and function normally. One zone,when heat is called for will turn the circulator pump on but the boiler does not respond. The system has 3 circulators,3 Honeywell R832A relays and an Aquastat relay. Thanks.


  • KCA_2
    KCA_2 Member Posts: 308
    Hi.. those are switching relays.... made to turn on a circulator, or whatever, when activated. If it's not a wiring issue, loose or wires that came apart, it likely just needs to be replaced. The wiring on the X X terminals should go to the boiler. The TT terminals should go to the T- Stat. It's possible one of the XX terminal wires are loose or that the contact went bad.... if so just replace..
    Call someone with a license to do this work. 120V is in the box and can be dangerous.
    :-)) Ken
    :-) Ken
  • lrodptl
    lrodptl Member Posts: 10
    edited October 2018
    Thanks Ken. The other 2 Tstats will energize the circulators and the Aquastat relay which fires off the boiler. This Tstat which I changed with a known good one will energize the circulator but the Aquastat relay does not close. I checked all the wires and they are good. So I should change out the R832A associated with that circulator? Thanks.
  • lrodptl
    lrodptl Member Posts: 10
    Changing the associated RA832A fixed it,thanks.