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3 wire steam zone valves

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TonyS
TonyS Member Posts: 849
in Strictly Steam
Restarting a steam system that has been shut down for 5 years. Zone valves are Honeywell 3 wire R W B connected to Honeywell 3 wire t 87 fs. What do I need to do to convert these zone valves to 2 wire stats?

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  • Dave in QCA
    Dave in QCA Member Posts: 1,786
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    You Can't

    On this type of setup, one wire is common, one wire opens the valve, the other wire closes the valve.  It simply requires 3 wires.

    Why to you wan't a 2 wire thermostat?
    Dave in Quad Cities, America
    Weil-McLain 680 with Riello 2-stage burner, December 2012. Firing rate=375MBH Low, 690MBH Hi.
    System = Early Dunham 2-pipe Vacuo-Vapor (inlet and outlet both at bottom of radiators) Traps are Dunham #2 rebuilt w. Barnes-Jones Cage Units, Dunham-Bush 1E, Mepco 1E, and Armstrong TS-2. All valves haveTunstall orifices sized at 8 oz.
    Current connected load EDR= 1,259 sq ft, Original system EDR = 2,100 sq ft Vaporstat, 13 oz cutout, 4 oz cutin - Temp. control Tekmar 279.
    http://grandviewdavenport.com
  • Unknown
    Unknown
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    TonyS

    It depends on the type of valve you have,, as far as I can see Honeywell only has 1 spring return actuator.

    http://customer.honeywell.com/TechLit/pdf/63-0000s/63-1257.pdf
  • TonyS
    TonyS Member Posts: 849
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    I was looking for a way to use

    an off the shelf Tstat. I suppose I could incorporate a double pole relay to energize the off cycle. Thanks
  • TonyS
    TonyS Member Posts: 849
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    I will have to get

    the model numbers Dave. They look pretty old. They are not spring return and they use a cam to close an isolated end switch that in turn completes the circuit on this millivolt steam boiler. 
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,578
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    valve changeout

    http://www.valvestore.com/



    these people have all sorts of valves-can you change the ones you have now for new ones?--nbc
  • Dave in QCA
    Dave in QCA Member Posts: 1,786
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    you could keep the t87f

    You could save money on the job and keep the T87F thermostats.  They are about as reliable as they come.

    If you are looking for something that is programmable, there are plenty of those available that are 3-wire.  Should'nt be that hard to find them, there are plenty of those good old 3 wire zone valves around.  They don't stick open or closed, they just keep working. That's probably why Honeywell doesnt make them anymore, too reliable!
    Dave in Quad Cities, America
    Weil-McLain 680 with Riello 2-stage burner, December 2012. Firing rate=375MBH Low, 690MBH Hi.
    System = Early Dunham 2-pipe Vacuo-Vapor (inlet and outlet both at bottom of radiators) Traps are Dunham #2 rebuilt w. Barnes-Jones Cage Units, Dunham-Bush 1E, Mepco 1E, and Armstrong TS-2. All valves haveTunstall orifices sized at 8 oz.
    Current connected load EDR= 1,259 sq ft, Original system EDR = 2,100 sq ft Vaporstat, 13 oz cutout, 4 oz cutin - Temp. control Tekmar 279.
    http://grandviewdavenport.com
  • Dave in QCA
    Dave in QCA Member Posts: 1,786
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    Here's a 3-wire programmable heat only T'stat

    http://www.amazon.com/White-Rodgers-1F80-0471-Programmable-Non-Programmable/dp/B0035UGKJM
    Dave in Quad Cities, America
    Weil-McLain 680 with Riello 2-stage burner, December 2012. Firing rate=375MBH Low, 690MBH Hi.
    System = Early Dunham 2-pipe Vacuo-Vapor (inlet and outlet both at bottom of radiators) Traps are Dunham #2 rebuilt w. Barnes-Jones Cage Units, Dunham-Bush 1E, Mepco 1E, and Armstrong TS-2. All valves haveTunstall orifices sized at 8 oz.
    Current connected load EDR= 1,259 sq ft, Original system EDR = 2,100 sq ft Vaporstat, 13 oz cutout, 4 oz cutin - Temp. control Tekmar 279.
    http://grandviewdavenport.com
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