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Want to Replace Honeywell R8182D with three wire system

rickthebuckeye Member Posts: 3
I have an old R8182D oil control aquastat. I would like to put in a smart thermostat, but my current set up has only two wires. What control/aquastat do I replace my old one with? And can I do it myself?



  • Jamie Hall
    Jamie Hall Member Posts: 18,943
    If by "smart" you mean Wi-Fi or internet aware, you are going to need the third, common wire. Those things suck power. You need to check if your system is 24 volt, and if it is use a common feed from the 24 volt transformer to the thermostat.

    If, on the other hand, you mean programmable, there are a number of battery powered programmables -- I like the Honeywell VisionPro series, but there are other just as good (and some not so good...) which will do the job on two wires.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • rickthebuckeye
    rickthebuckeye Member Posts: 3
    Thank you. Yes I mean a WiFi enabled thermostat. I know about the third wire, and I'm not sure about the 24V on my current system. If I could just tap into the 24V (if that's what it is) that would be awesome.

    I guess I need to figure out if the transformer in the control box is 24V and if I can tap into it. Any suggestions?
  • STEVEusaPA
    STEVEusaPA Member Posts: 5,689
    Get a separate 24v transformer.
  • rickthebuckeye
    rickthebuckeye Member Posts: 3
    Any suggestions where to get one and where do I mount it?
  • Dan_NJ
    Dan_NJ Member Posts: 211
    I found one at a local home center once. In that case I mounted it on a wall and fed it with an inverter to keep the heat on in mid-winter extended power outage. You would mount in a standard electrical box and feed from utility/circuit.
    HVACNUT Member Posts: 4,594
    Is there air conditioning being wired into the wifi stat? If so, it might have an extra wire for a Common, or maybe run a new thermostat wire from the air handler.
    If I remember right, the R8182D is a triple aquastat/primary?
    If the above can't be done, you can install a 1 zone switching relay.(Taco, Argo etc.) Either offers a Common connection. This will need 3 conductors. Do you have an extra wire to use? Bring the thermostat wire and circulator wires to the new zone relay. Run a 2 wire from TT in the aquastat to N.O. dry contacts on the zone relay.
    I dont know if Honeywell still makes the R8182D. Even remanufactured might be $$$.
    If you can, install a new triple aquastat and a 15 sec primary control.
    Robert O'Brien
  • Steamhead
    Steamhead Member Posts: 15,334
    edited May 2018
    Simplest way would be to use a Honeywell R8285B (DPDT) or R8239A (SPDT) fan center relay, which has its own 40 VA transformer. This mounts on a standard 1900 box (4" square). You'd power your thermostat from the transformer's R and C terminals, and connect the switched (usually white) wire to terminal G which operates the relay. Then you'd wire the normally-open relay contact to TT on the R8182D.

    Does your boiler have a tankless coil to heat your hot faucet water?
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • GBart
    GBart Member Posts: 746
    1 800 - call a pro