Ask Experts Questions for FREE Help !
Ask
    essuo's Avatar
    essuo Posts: 17, Reputation: 1
    New Member
    		  
    #1

    Oct 23, 2009, 07:58 AM
    Installing a new 24V Honeywell AT72D transformer
    The old transformer had 4 wires different colors. New Honeywell AT72D has Primary BLK-COM, WHT-120V 50/60Hz, and two screws on the load side with an R and C. I thought it would be obvious, but it is not to me. Do I have it right? PR1-BLK, PR2-WHT Secondary I am not sure which should go where? SEC1/SEC2 R or C?

    Thanks
    KISS's Avatar
    KISS Posts: 12,510, Reputation: 839
    Uber Member
    		  
    #2

    Oct 23, 2009, 08:20 AM

    Here is the installinstructions:

    http://customer.honeywell.com/techli...0s/60-0428.pdf

    You failed to say what colors the old transformer had. If it had a white and a black connected to the primary side, white and black are appropriate.

    The red and orange wires should each have a wirenut placed on the ends (capped).

    The secondary phasing only matters with newer furnaces with flame rectification flame proving systems. In which case, an error code will be set on the control board. No damage will result.
    essuo's Avatar
    essuo Posts: 17, Reputation: 1
    New Member
    		  
    #3

    Oct 23, 2009, 09:11 AM

    Primary colors on the old were Black - PR1 and White PR2 and Secondary colors were Red for SEC-1 and Blue for SEC-2 My furnace is at least 20 years old, so it should not matter where SEC wires go. Thanks for your answer.
    KISS's Avatar
    KISS Posts: 12,510, Reputation: 839
    Uber Member
    		  
    #4

    Oct 23, 2009, 09:45 AM

    Yep.
Not your question? Ask your question View similar questions
 

Question Tools Search this Question
Search this Question:

Advanced Search

Add your answer here.


Check out some similar questions!

Installing transformer for Alarm System [ 10 Answers ]

Hello I am wanting to install a new transformer for my alarm system. The old one was taken out by a friend and was incorrectly installed according to him (an electrician). It is a 16.5 V transformer which sat at the bottom of the panel. It has 2 black wires coming from it. There is a place...

Installing Honeywell Thermostat [ 13 Answers ]

I'm installing new thermostat - all wires/lettering corresponds from old to new with the exception of new one has a slot for "w"but I have two wires left "w1" and "w2". "W1" is tan and "w2" is yellow. Thanks for the help!

Installing Honeywell RTH7400D [ 8 Answers ]

I am installing a Honeywell RTH 7400 D. The old thermostat did not have lables on the wires. There is a Red White and Blue Wire. I believe the Red will go the Rh and the White to W but I do not know where to connect the Blue.

Installing Honeywell RTH6300B from an older 7 wire Honeywell. PROBLEMS [ 4 Answers ]

Hello everyone, I am new here. I found this site which trying to troubleshoot my problem. Any assistance would be GREATLY appreciated. Basically I have an older honeywell programmable thermostat with 7 wires attached. They are as follows... C - Black wire L - Blue wire R- Red wire W2 - brown...

Installing Honeywell RTH7400 [ 1 Answers ]

I am replacing my old thermostat with a new Honeywell RTH7400. Here are the wire terminals from my old one: G Y T R O W B X2

View more questions Search