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    stewart windeler's Avatar
    stewart windeler Posts: 1, Reputation: 1
    New Member
    		  
    #1

    Apr 12, 2007, 10:15 AM
    Ruud varible speed air handler
    I am installing a new two stage heat pump, rudd IUHPL. The 24 volt transformer is in the air handler. The transformer is energized and putting out 24 vt. Which enters the circuit board. The red wire leaving the board is 0 vt. As I understand the system this red wire is supposed to supply 24 vt to the thermostat and outside unit. Are my assumptions correct?
    What conditions can cause this problem? The service books shipped with the units are not correct and do not include wiring diagrams or a help number to call at Ruud.
    JackT's Avatar
    JackT Posts: 260, Reputation: 19
    Full Member
    		  
    #2

    Apr 12, 2007, 01:42 PM
    I'm not familiar with this model but some have door switches that won't allow the unit to operate unless the blower door is closed. Sorry, but that's all I can suggest without the diagram.
    T-Top's Avatar
    T-Top Posts: 1,871, Reputation: 100
    Ultra Member
    		  
    #3

    Apr 12, 2007, 07:26 PM
    If you have 24 volts from the transformer in to the control board and not at the R and C on the board you have a blown low voltage fuse or open limit. Check the fuse first (3 or 5 amp automotive fuse center of the board).
    hvac1000's Avatar
    hvac1000 Posts: 14,540, Reputation: 435
    Heating & Air Conditioning Expert
    		  
    #4

    Apr 12, 2007, 07:38 PM
    If it is a true variable speed DC motor circuit you will also have to set the dip switches to match your system.
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