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Hot water zone on steam boiler

Safir
Safir Member Posts: 17
Add a hot water zone off my steam boiler with a separate thermostat can someone help me with the wiring part? I am planing to use a aquastat so it can fire burner without producing steam for upper floors. 

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 18,903
    The aquastat can be wired in parallel with the steam thermostat. Then either one will fire the boiler. Presumably you have a circulator pump on the hot water loop -- that would be controlled by the thermostat in the space you are heating with the loop.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    Safir
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 11,985
    @Safir

    Yes as @Jamie Hall said install an aquastat that has contacts that "make on temperature fall" and wire from the aquastat a 2 wire cable in parallel with the thermostat that runs the boiler for steam. So it will connect to the same terminals on the boiler control that the thermostat connects to.

    Then for your circulator buy a Honeywell RA89A switching relay. There are others by Taco & Argo that are =.

    Run a two wire cable form you new hot water zone thermostat to the new relay mounted near the boiler and connect terminals R & W in the thermostat to T & T in the relay.

    Then you need 120 volt power off the boiler to power terminals 1 (hot) and 2 (neutral) in the relay. Also pull a green or bare ground wire or use a metal raceway.

    From your new circulator pump wire to the new relay white to term #2, hot for the pump to term #4. Put a jumper between terminal 1 & 3 on the relay if not factory installed.

    Run a ground wire from the circ pump to the relay
    Safir
  • Safir
    Safir Member Posts: 17
    Thanks for the prompt response yes I have a circulator on the loop. I have a taco single zone relay, l4006 aquastat and thermostat will these work? Thanks
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 11,985
    The aquastat will be ok. Don't know what you have for a t stat or relay
  • Safir
    Safir Member Posts: 17
    I have a sr501-4 1 zone relay will that work? I have a Honeywell thermostat battery operated
  • Safir
    Safir Member Posts: 17
    Also when upstairs call for steam I would like circulator to run also. The wiring Jamie explain will that happen?
  • Jamie Hall
    Jamie Hall Member Posts: 18,903
    Safir said:

    Also when upstairs call for steam I would like circulator to run also. The wiring Jamie explain will that happen?

    No. The circulator would only run when the its own thermostat is calling for heat. If you want both the upstairs thermostat and the zone's own thermostat to run the circulator, then you will need a relay controlled by the upstairs thermostat. If you want the hot water circulator to run either when its thermostat is calling or when the upstairs thermostat is calling, but not necessarily when the aquastat is calling, then you need two relays, one controlled by each thermostat, and the wiring gets interesting, though not complicated.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Safir
    Safir Member Posts: 17
    Ok thanks I guess it's not important to have it run on both thermostat will keep you posted how it goes thank you again
  • mattmia2
    mattmia2 Member Posts: 5,503
    Safir said:

    Ok thanks I guess it's not important to have it run on both thermostat will keep you posted how it goes thank you again

    I don't see why you would want to do that. You have 2 independent zones without it, with it you run the risk of overheating the hot water zone.
    Safir
  • Safir
    Safir Member Posts: 17
    On the relay the part that say connect to tt on boiler where do I connect that ?
  • HVACNUT
    HVACNUT Member Posts: 4,589
    edited September 2021
    Safir said:
    On the relay the part that say connect to tt on boiler where do I connect that ?
    TT (or R-W) on the SR501 go to the thermostat for the new zone. 
    Terminals 5 and N.O. 6 get wired in parallel with the wires for the steam thermostat. 
  • Safir
    Safir Member Posts: 17
    Ok so terminals 5 and 6 wire parallel with steam thermostat and the aquastat too the same way?
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 11,985
    edited September 2021
    @Safir

    There's two ways to do this.

    1..You can use the aquastat to maintain a hot boiler 24/7 then use the new thermostat for the hot water zone to start the circulator.

    That is called a non integrated control

    OR

    2. Or you can use the aquastat as a limit control for the boiler (the boiler will be cold unless the steam or hot water thermostat is calling for heat)

    Then the new hot water thermostat will run the boiler (if below the aquastat setting) and run the new circ pump.

    This is an integrated control

    Which one do you want? Does your boiler heat Domestic Hot Water?

    #2 involves more wiring

    Once you decide I will post a wiring diagram

  • Safir
    Safir Member Posts: 17
    Yes the #2 is exactly what I am trying to do. No not using to heat domestic water

  • Safir
    Safir Member Posts: 17
    For the record I have a crown Bermuda steam boiler
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 11,985
    @Safir

    this should do it
  • Safir
    Safir Member Posts: 17
    Thankyou very much that makes it so easy
  • Safir
    Safir Member Posts: 17
    Will post results when finish
  • Safir
    Safir Member Posts: 17
    I have been thinking with the wiring diagram if the aquastat is satisfied and upstairs thermostat is calling for heat wouldn't the aquastat prevent the burner from firing? Maybe I am overthinking but I ask anyway
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 11,985
    Ok this is how it works:

    Steam side:

    Steam thermostat calls for heat, boiler fires up and makes steam, radiation gets hot,rooms heat thermostat is satisfied boiler shuts down.

    Hot water zone"

    Thermostat calls for heat, new relay pulls in and starts circulator pump. It will also start the boiler IF the boiler water temp is below what the aquastat is set for. So if the boiler is already hot from steaming and the hot water zone calls for heat the burner will not fire until the aquastat calls for the burner

    The purpose of the aquastat is to limit the boiler water temp so the boiler won't make steam (and heat the steam radiators) with only the hot water zone calling for heat

  • Safir
    Safir Member Posts: 17
    Wow interesting well explain thank you
  • Safir
    Safir Member Posts: 17
    I finally get around to this I wire as shown its working burner is firing baseboard warming up but I notice once it hit temp I think Aquastat needs to be reset manually for it to fire again. Any suggestions?
  • Safir
    Safir Member Posts: 17
    This is the aquastat I am using l4006e1109 break on rise
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 11,985
    @Safir

    Yes you bought the wrong aqustat the L4006e is a manual reset you can't use that.

    You could use a L4006A get one with an adjustable differential
  • Safir
    Safir Member Posts: 17
    Ok will do thanks
  • Safir
    Safir Member Posts: 17
    I replace the Aquastat works perfect. Would like to thank everyone here for helping out.