问题出在低压(24V)电路。cooling is not controled by the board. it iis by t

因此换board 不解决问题很正常。here is what you need to do:
1)check if you have 24v between R and C. Voltage=0,?bad transformer; v=24, go to next
2)at the board, put a jump wire between R and Y (connect R & Y), condenser should be on since you have a new contactor. If not, bad wire between board and contactor.
3)jump R and G, blower should be on.
4)If 2) and 3) both are working, the problem is your thermostat or wire between the board and thermostat.

所有跟帖: 

transformer is not easy to bad. when it did, 90% of time -TDF樂在其中- 给 TDF樂在其中 发送悄悄话 (311 bytes) () 05/20/2015 postreply 07:29:57

good catch! reminded me that the plug pin on soldered to PCB oft -chinomango- 给 chinomango 发送悄悄话 chinomango 的博客首页 (113 bytes) () 05/20/2015 postreply 11:23:10

赞非常专业详尽的解说! -瞎问瞎说- 给 瞎问瞎说 发送悄悄话 瞎问瞎说 的博客首页 (0 bytes) () 05/20/2015 postreply 09:52:14

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