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    onle a sparky's Avatar
    onle a sparky Posts: 6, Reputation: 1
    New Member
     
    #1

    Jan 5, 2009, 08:23 AM
    Blower would not work on AUTO position just ON position
    I have installed new rooftop unit- electrical heating & cooling- few weeks ago. When I run the cooling everything goes fine (blower and composer) but if I run the heating; heat element will fire up but the blower will not work unless I put the fan on ON position not AUTO position, so, please, I need to know is it the T-stat or the unit itself. Thank you
    hvac1000's Avatar
    hvac1000 Posts: 14,540, Reputation: 435
    Heating & Air Conditioning Expert
     
    #2

    Jan 5, 2009, 10:53 AM
    It could be almost anything on the NO NAME BRAND-NO EXACT MODEL NUMBER unit.

    Since there are about 2,327 different ones it is really hard to tell. Sorry.
    onle a sparky's Avatar
    onle a sparky Posts: 6, Reputation: 1
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    #3

    Jan 5, 2009, 07:38 PM

    OK, my bad:) it is Carrier, model: 50SD, sigle-package Electrical Cooling/Heating Units.

    It has 2 separate unites; AC unit and Heating unit with separate control leads. 1st control lead includes: Brown for common, Red for power, Yellow for cooling and Green for fan blower. 2nd control leads includes: Brown for common, White for stage one heating and violet for stage 2 heating.

    I connected the Browns together( Brown wire in cooling control with Brown wire in heating control, then I connected Red wire in Unite to R terminal in T-stat, Green wire in unite to G terminal in T-stat, Yellow wire in unit to Y terminal In T-state, White wire in unite to W1 in


    T-stat and Violet wire in unit to W2 in T-stat.

    The problem I have; if the T-stat in Auto and run the heat, the Blower will NOT run but if I change the Blower to on it will work just fine.
    I do not get to same problem if I run cooling even the blower in Auto position, every thing run fine.

    I checked all connections, I changed the T-stat to new and deferent T-stat; I still get the same problem. Please if you can help please do so. Sparky
    greghvacguy's Avatar
    greghvacguy Posts: 45, Reputation: 2
    Junior Member
     
    #4

    Jan 5, 2009, 07:50 PM

    Not sure on that unit but you need to find out if the unit controls the fan in heating. If not you need to set your t-stat to turn fan on when a call for heat. Depends on your t stat how you set that. You need to set the t-stat for electric heat
    KC13's Avatar
    KC13 Posts: 2,556, Reputation: 99
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    #5

    Jan 5, 2009, 07:55 PM
    Check the thermostat for a switch or selection jumper with positions for "gas" or "electric". Set it to "Electric".
    onle a sparky's Avatar
    onle a sparky Posts: 6, Reputation: 1
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    #6

    Jan 5, 2009, 08:02 PM

    I do not have this option, Do you have any brand and model suitable to work with this unit
    MarkwithaK's Avatar
    MarkwithaK Posts: 955, Reputation: 107
    Senior Member
     
    #7

    Jan 5, 2009, 08:05 PM
    Quote Originally Posted by onle a sparky View Post
    I do not have this option, Do you have any brand and model suitable to work with this unit
    Most quality stats will be compatible with electric or gas. Did you look at the circuit board of the stat for the selector switch? It will NOT be on the exterior of the stat.
    KC13's Avatar
    KC13 Posts: 2,556, Reputation: 99
    Ultra Member
     
    #8

    Jan 5, 2009, 08:05 PM
    Quote Originally Posted by onle a sparky View Post
    I do not have this option, Do you have any brand and model suitable to work with this unit
    Are you sure? It could be on the back of the thermostat or sub-base. Check the installation instructions if available.
    onle a sparky's Avatar
    onle a sparky Posts: 6, Reputation: 1
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    #9

    Jan 5, 2009, 08:19 PM

    I'm not sure, it's late to go back now but I'll go 1st in the morning, you guys saved my ###, thank you very, very much. I'll late you know tomorrow. Thanks
    hvac1000's Avatar
    hvac1000 Posts: 14,540, Reputation: 435
    Heating & Air Conditioning Expert
     
    #10

    Jan 5, 2009, 10:35 PM
    Quote Originally Posted by onle a sparky View Post
    I'm not sure, it's late to go back now but I'll go 1st in the morning, you guys saved my ###, thank you very, very much. I'll late you know tomorrow. thanks

    One note from your install instructions.

    NOTE: Do not use any type of power-stealing thermostat. Unit
    control problems may result.
    Also

    1. Place room thermostat SYSTEM switch in OFF position.
    Observe that blower motor starts when FAN switch is placed
    in ON position and shuts down after 30 second fan time delay
    expires when FAN switch is placed in AUTO position.

    NOTE: To enable fan ON activation the thermostat you use must have a R to G connection built into the thermostat or thermostat subbase.

    Also check status and wiring of TDR (time delay relay). If you need to change blower speeds to maintain unit specs the TDR is where you do it. Usually the fan speed selected at the factory works well.

    Here is complete install instructions for that Carrier. I have placed a sub-channel call into one of my engineering friend at Carrier. Now they are building them with no relay for speed selection between heat and cool. How cheap can they get. LOL

    http://www.xpedio.carrier.com/idc/gr...t/50sd-1si.pdf

    BTW The two brown wires that are twisted together would be for the C terminal on the thermostat if it had a C terminal. It is the common leg or the 24 volt control circuit.

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