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CT2700

BillW@honeywell
BillW@honeywell Member Posts: 1,099
in THE MAIN WALL
The resistor is a 7.87K ohm type. It's used with power stealing stats on TACO green zone valves, on terminals 1&2, or on the Honeywell R8184G oil primary between the lower T & lower F terminals. There is a Honeywell part number for it, 4074EYC. If you like to upgrade to a trade model, use the T8002C1000. That is battery powered digital programmable, compatible with steam, hydronic or forced air.Since I have no information on the retail product, I can't be certain that the resistor will solve your problem. Any Honeywell distributor will have the T8002C1000, or can order it. Take care!

Comments

  • Turkeyherder
    Turkeyherder Member Posts: 2
    Honeywell CT2700

    Installed two W/M CGs using CT2700 T-stats.
    The T-stats lose their display when the boilers are on.
    Display returns and program is normal when boiler shuts down. Any suggestions. Anyone have the link to honeywells tech site?
    Thanks
  • BillW@honeywell
    BillW@honeywell Member Posts: 1,099
    CT2700

    Those stats are retail models sold only through Home Depot or Lowes or other box stores. I do not have any information on the retail lines, but the symptoms you describe are consistent with power stealing thermostats blanking out on startup, due to losing power. Trade model stats come with a resistor to add into the system, but I doubt that the retail models include them, and they are not available at the box store. You best solution would be to use a battery powered thermostat, or call a professional, using the "find a contractor" feature above.
  • Turkeyherder
    Turkeyherder Member Posts: 2


    Thanks Bill. VERY INTERESTING.The homeowner provided the t-stats because the wife liked the design.
    Do you know the resistor size? Or should I swap to a couple of T8400's
  • tim from Reed Wright
    tim from Reed Wright Member Posts: 113
    losing display

    another option we have done many times is install a isolation relay on equipment, then you wont lose feed back power which these stats rely on. Go from transformer on equip and run common to one side of coil and R off transformer up through thermostat and to other side of coil. then use the contacts on relay to switch T&T on unit. This will take care of power loss to thermostat.
  • Glenn Harrison
    Glenn Harrison Member Posts: 405
    I don't know if this is too little, too late,

    but if it helps you, here is a link to installation instructions for the CT2700 T-stats. It appears to be the same as the Trade version T8700 series digital round t-stat, which I believe has been discontinued, but Bill W. can feel free to correct me on that.

    http://hbctechlit.honeywell.com/techlit/PDF/69-0000s/69-1085.pdf

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