Original message
| mikelb5
 |  "Bryant Combo Unit - No operation"
, posted Sat 6 Aug 11:24  
I have an older 584A Bryant combination heat/ac "rooftop" unit. A few nights ago the unit stopped functioning (blower, ac, and heat). Checked for 24v at the contactor and nothing. Pulled the secondary side of the transformer and checked for 24v to find nothing. The transformer states on the side that it has circuit protection and wait 15 min. for reset. Did that and turned power on to find 24v at the secondary of transformer. So I replaced the main circuit board (HH84AA017 Carrier-BDP). I'm still having the same problem. The only other solution I can come up with is to replace the piggy back time delay board (HH84AA018 Carrier-BDP). Am I going in the right direction, or should I be looking at the blower, limit switches, etc.
Any help would be much appreciated.
Thanks
Michael
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Replies:
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| MasterTech
| "Re(1):Bryant Combo Unit - No operation" , posted Sat 6 Aug 11:40
I would look at the contactor. Ohm out the contactor coil.
I have found that any thing under 9ohms will slowly short out a 40va transformer(24vac).
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| | mikelb5
| "Re(2):Bryant Combo Unit - No operation" , posted Sat 6 Aug 12:03
Just did that and it's reading roughly 9.25ohms. If it is causing the transformer to short out, when I press the button on the contactor would just the ac kick on and not the blower?
Any help would be much appreciated.
Thanks
Michael
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| | MasterTech
| "Re(3):Bryant Combo Unit - No operation" , posted Sat 6 Aug 12:34
I would do an amp drawn test(need a clamp on meter). A 40va Xformer should not draw more then 1.5 amps continously. If you are drawning that much or more find out what component that is causing it.
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