Basement A/C units run constantly

[Fred Brooks]

http://beaveramb.org/forum/index.php/topic,4671.msg35204.html#msg35204
 Sorry about that, computor stuff still a challenge for old techs.

[Ron Rittenhouse]

Fred,
Will uninstall T-stat again and test the wiring coming in at bottom of control panel area.  If it shows no 12v hot, will turn focus to relays.  If black wire shows 12v hot and wiring issue, where to start is the next question.  If it's relays, would you still suggest replacing thermostat with Coleman?  Will keep you posted on developments.  Thanks, again. Ron

[Fred Brooks]

   Ron,
 You are on the right tract and thanks for hanging in there. Once you figure it out, joy will be your reward!. Normally relay 5 and 6 only activate when they see 12volt from the t-stat. If a 12volt source is accidently powering up the black wire, you get the blowers. With the t-stat connected but turned off, the black wire should not have 12 volt.
  I would definitely install the Coleman t-stat once you solve your issue. It has a digital read out of room temperature and set points and works well with the Hurricane furnace/water heater. Another feature is if left on "auto" and it calls for cooling, it only turns on compressor #1 to try and maintain ambient temperature to save power. If not satisfied, it turns on compressor #2 also to satisfy your set point. Blessings, Fred

[Ron Rittenhouse]

Fred,
Thanks very much. Worked yesterday, but plan to use probe tester on black wire today after uninstalling t-stat (again). If black wire hot, will try to track down why.  Sincerely hoping it's relays. will let you know. Been trying to focus thinking in this direction: Phil. 4:4-7. Blessings,
Ron

[Fred Brooks]

   Hey Ron,
  Enclosed please find some pix of the T-Stat wiring as it enters the air conditioner @lower right side corner. You will notice that there are 3 spare wires that are not being used. Brown, Green, and white. In the event the black wire picked up 12 volt from an unknown source, you can isolate it at each end and then use the brown wire to replace it. If the #5 & #6 relays are stuck in the run position, you will have to replace them.
  When my outside blower relay failed on my PC board, you can see where I temporarily installed a cole hersey 12 volt 30 amp relay so I could use the coach air conditioner.
  Best part about Phil 4: 6-7 it is my favorite verse and He has the Power to guard my Heart. Blessings, Fred

[Fred Brooks]

  Ron, here is the other 2 pix

[Fred Brooks]

   Greetings,
For those folks that are following this post and have the SCS basement air conditioner, we have traced the failure to the PC board Relay #RL-2. It is the relay that controls the evaporator and condenser blower motors. It is a common failure on the board. The part # for the relay is RH4V2-U-DC110V. Hope this helps, Fred