bryant split a/c outside condenser fan and compresser wont shut off
#1
11-28-17, 08:01 AM
bryant split a/c outside condenser fan and compresser wont shut off
I have a 5 yr old Bryant 2.5 ton system, just recently the outside unit does not cycle off.
the thermostat seems to be working it cycles on maintains temp, thermostat clicks off , blower
fan shuts down but outside unit stays running, the only way to shut down the unit is to shut off the breakers
at the box. so I thought the contactor was like stuck in the engaged mode, so I replaced that and a new
capacitor and still does not shut down unless I physically turn breakers off. what I'm I missing here.
the thermostat seems to be working it cycles on maintains temp, thermostat clicks off , blower
fan shuts down but outside unit stays running, the only way to shut down the unit is to shut off the breakers
at the box. so I thought the contactor was like stuck in the engaged mode, so I replaced that and a new
capacitor and still does not shut down unless I physically turn breakers off. what I'm I missing here.
#2
11-28-17, 11:38 AM
Group Moderator
Welcome to the forums.
Several things to try......
Remove the thermostat from the sub base and see if the condensor shuts off.
If not.... remove the two low voltage wires on the side of the contactor and see what that does.
Several things to try......
Remove the thermostat from the sub base and see if the condensor shuts off.
If not.... remove the two low voltage wires on the side of the contactor and see what that does.
#3
11-28-17, 01:48 PM
pete, I pulled the low voltage wires on each side of the contactor and it disengaged the contactor
but when I put them back on it started up the fan and compressor, even thou the thermostat was off.
but when I put them back on it started up the fan and compressor, even thou the thermostat was off.
#4
11-28-17, 02:22 PM
Group Moderator
So the contactor is receiving 24vac when it shouldn't be.
Your next step is to pull the thermostat off its sub base and see if that shuts it off.
Your next step is to pull the thermostat off its sub base and see if that shuts it off.
#5
12-01-17, 05:46 AM
pete, if by pulling the sub base off while the unit is running, and it shuts off, what would be my next step.
what else is there to check. but if the thermostat stays running then its time for a new one. I did replace
the one that's in there about a year ago, digital readout, Honeywell.
what else is there to check. but if the thermostat stays running then its time for a new one. I did replace
the one that's in there about a year ago, digital readout, Honeywell.
#6
12-01-17, 07:40 AM
Member
Hi, sounds like a short between the yellow and red ,I would mark the wires as to which one is on which terminal, remove them from the subbase pull out from the wall a bit and check for any bare spots in the insulation,if all is well then reinstall the conductors leaving the yellow or Y1 off until last check all Tstsat functions before reattaching it.
Geo
Geo
#7
12-01-17, 05:29 PM
Group Moderator
Sounds like a defective thermostat. The Y (condensor) wire is permanently connected to the R (24v) wire. Replace the thermostat.
#8
12-04-17, 03:44 PM
pete, I pulled the thermostat off the sub base and the outside compressor continues the run, the
blower fan cycled off. the only way to shut down the outside compressor is at the breaker box. wtf.
blower fan cycled off. the only way to shut down the outside compressor is at the breaker box. wtf.
#9
12-04-17, 05:43 PM
Group Moderator
The way you worded sounded like you already tried it.
Your next step is to go to the air handler and disconnect the wiring there. There may possibly be a wire touching on the terminal strip.
The colors of the wiring coming from the thermostat that you are interested in should be (Y) yellow and (R) red. The red wire will be connected to R in the air handler. The yellow wire may connect to the terminal strip (Y or it may just connect to the wiring going outside.
The red wire is the 24v source. The yellow wire is switched 24v to the condensor. You are looking for a short between the two. The short would be at the air handler or between the air handler and the thermostat.
Your next step is to go to the air handler and disconnect the wiring there. There may possibly be a wire touching on the terminal strip.
The colors of the wiring coming from the thermostat that you are interested in should be (Y) yellow and (R) red. The red wire will be connected to R in the air handler. The yellow wire may connect to the terminal strip (Y or it may just connect to the wiring going outside.
The red wire is the 24v source. The yellow wire is switched 24v to the condensor. You are looking for a short between the two. The short would be at the air handler or between the air handler and the thermostat.
#10
12-04-17, 07:28 PM
Forum Topic Moderator
It might also help if we knew a little bit more about this system.
Is this a heat pump? Is this a split system?
A heat pump or package unit can have this problem caused by a short in the wiring running outside.
Is this a heat pump? Is this a split system?
A heat pump or package unit can have this problem caused by a short in the wiring running outside.
#11
12-05-17, 08:23 PM
pete, I bought a new digital thermostat today, checked the wires all looked fine.
hooked them to the appropriate terminals and got the same results. I did pull the y wire
off at the thermostat while it was running and nothing changed, stayed on blowing cool air
into the vents. ugh.
hooked them to the appropriate terminals and got the same results. I did pull the y wire
off at the thermostat while it was running and nothing changed, stayed on blowing cool air
into the vents. ugh.
#12
12-05-17, 09:50 PM
Group Moderator
Can we assume this is just a standard split A/C system.... not a heat pump ?
This is the basic diagram. You are somehow getting 24vac on the yellow (Y) wire when you shouldn't be. You need to go to the air handler and isolate the wiring.
This is the basic diagram. You are somehow getting 24vac on the yellow (Y) wire when you shouldn't be. You need to go to the air handler and isolate the wiring.
