Air Conditioning - AC fan runs continuously
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nancy
07-31-04, 05:57 PM
We are in 'fix broken things only' mode at this time (The economy).
AC unit was serviced, and the technician declared all in good shape. We were having problems with the fan running constantly, though the compressor turned on and off fine. He said if the problem continued, the thermostat was bad. Also, he said that a delay switch could possibly be bad; since there is a delay built into the thermostat, he removed the switch (I have it, and could put it back, if suggested).
Long story short: we're now on 3rd thermostat (#2 came from a giant retailer - I took it out/took it back after a couple of weeks; heck, every video I have bought there was defective, so....)
Anyway, the unit cools fine, but the fan just does not shut off - this is in 'auto' mode. If I switch the thermostat to 'off' it continues to run. If it has reached the proper temp., and compressor is off, I can put the fan switch on 'on' for a few moments, then put it on 'auto' - it will usually shut off in another few minutes. Then, when the unit starts up to cool again, the fan stays on...
I wired the new one just like the old - but that doesn't *necessarily* mean it is wired correctly!
Any suggestions gladly entertained. Of course, it could be worse - we could be roasting!
Thanks.
AC unit was serviced, and the technician declared all in good shape. We were having problems with the fan running constantly, though the compressor turned on and off fine. He said if the problem continued, the thermostat was bad. Also, he said that a delay switch could possibly be bad; since there is a delay built into the thermostat, he removed the switch (I have it, and could put it back, if suggested).
Long story short: we're now on 3rd thermostat (#2 came from a giant retailer - I took it out/took it back after a couple of weeks; heck, every video I have bought there was defective, so....)
Anyway, the unit cools fine, but the fan just does not shut off - this is in 'auto' mode. If I switch the thermostat to 'off' it continues to run. If it has reached the proper temp., and compressor is off, I can put the fan switch on 'on' for a few moments, then put it on 'auto' - it will usually shut off in another few minutes. Then, when the unit starts up to cool again, the fan stays on...
I wired the new one just like the old - but that doesn't *necessarily* mean it is wired correctly!
Any suggestions gladly entertained. Of course, it could be worse - we could be roasting!
Thanks.
bigjohn
08-01-04, 05:14 AM
We are in 'fix broken things only' mode at this time (The economy).
AC unit was serviced, and the technician declared all in good shape. We were having problems with the fan running constantly, though the compressor turned on and off fine. He said if the problem continued, the thermostat was bad. Also, he said that a delay switch could possibly be bad; since there is a delay built into the thermostat, he removed the switch (I have it, and could put it back, if suggested).
Long story short: we're now on 3rd thermostat (#2 came from a giant retailer - I took it out/took it back after a couple of weeks; heck, every video I have bought there was defective, so....)
Anyway, the unit cools fine, but the fan just does not shut off - this is in 'auto' mode. If I switch the thermostat to 'off' it continues to run. If it has reached the proper temp., and compressor is off, I can put the fan switch on 'on' for a few moments, then put it on 'auto' - it will usually shut off in another few minutes. Then, when the unit starts up to cool again, the fan stays on...
I wired the new one just like the old - but that doesn't *necessarily* mean it is wired correctly!
Any suggestions gladly entertained. Of course, it could be worse - we could be roasting!
Thanks.
Hi Nancy:
Can I assume it has not always dpne this? Also, you are referring to the indoor fan, right? If you have replaced the thermostat and the technician removed what sounds like a time delay for the indoor fan [the time delay keeps the indoor fan running for about 30 to 60 seconds after the t-stat is satisfied] I would say you probably have a sticking/intermittent indoor fan relay. This could be a cheap fix or an expensive fix depending on what type of heat you have and how the furnace/air handler is designed. On some units, there will be a separate indoor fan relay to replace. [the cheap fix] On some units, the indoor fan relay is integrated into a multifunction solid state board and the entire board would have to be replaced. [the expensive fix] This should be an easy diagnosis. The technician would check for power at the Fan terminal [G terminal] in the furnace/air handler when the problem is occurring. If the terminal is powered and shouldn't be, the problem is outside the furnace/air handler; but if the terminal is not powered the problem is inside the furnace/air handler.
AC unit was serviced, and the technician declared all in good shape. We were having problems with the fan running constantly, though the compressor turned on and off fine. He said if the problem continued, the thermostat was bad. Also, he said that a delay switch could possibly be bad; since there is a delay built into the thermostat, he removed the switch (I have it, and could put it back, if suggested).
Long story short: we're now on 3rd thermostat (#2 came from a giant retailer - I took it out/took it back after a couple of weeks; heck, every video I have bought there was defective, so....)
Anyway, the unit cools fine, but the fan just does not shut off - this is in 'auto' mode. If I switch the thermostat to 'off' it continues to run. If it has reached the proper temp., and compressor is off, I can put the fan switch on 'on' for a few moments, then put it on 'auto' - it will usually shut off in another few minutes. Then, when the unit starts up to cool again, the fan stays on...
I wired the new one just like the old - but that doesn't *necessarily* mean it is wired correctly!
Any suggestions gladly entertained. Of course, it could be worse - we could be roasting!
Thanks.
Hi Nancy:
Can I assume it has not always dpne this? Also, you are referring to the indoor fan, right? If you have replaced the thermostat and the technician removed what sounds like a time delay for the indoor fan [the time delay keeps the indoor fan running for about 30 to 60 seconds after the t-stat is satisfied] I would say you probably have a sticking/intermittent indoor fan relay. This could be a cheap fix or an expensive fix depending on what type of heat you have and how the furnace/air handler is designed. On some units, there will be a separate indoor fan relay to replace. [the cheap fix] On some units, the indoor fan relay is integrated into a multifunction solid state board and the entire board would have to be replaced. [the expensive fix] This should be an easy diagnosis. The technician would check for power at the Fan terminal [G terminal] in the furnace/air handler when the problem is occurring. If the terminal is powered and shouldn't be, the problem is outside the furnace/air handler; but if the terminal is not powered the problem is inside the furnace/air handler.
Ed Imeduc
08-01-04, 08:33 AM
Pull G off tstat if fan still runs go to unit and hit the side of it real hard with your hand See if it stop's. If not from what you said you could have another time delay in there.
I can put the fan switch on 'on' for a few moments, then put it on 'auto' - it will usually shut off in another few minutes. Then, when the unit starts up to cool again, the fan stays on...
ED ;)
I can put the fan switch on 'on' for a few moments, then put it on 'auto' - it will usually shut off in another few minutes. Then, when the unit starts up to cool again, the fan stays on...
ED ;)