Trane fan dosnt shut off even when compressor will

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Old 07-20-13, 04:06 PM
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Trane fan dosnt shut off even when compressor will

I have a Trane model 4wcc3036a1000ab 3 ton unit. the fan runs almost all the time but the unit (compressor) cycles normally. I have had several technicians come and look at the problem. Its cooling fine but the fan will not cut off all day.Whats weird is we will wake up in the morning and the fan will be off like its supposed to most of the time. A tech came and replaced the thermostat as well with a Honeywell Vision Pro 8000 and I think that's when the fan problem started. I bought a Honeywell RTH221B and tried to replace the 8000 but the fan would run but the compressor wouldn't come on. So I swapped them back. Im at a loss
 
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Old 07-20-13, 05:04 PM
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When you say the fan doesn't shut off, which fan do you mean, the air handler (blower) fan or the condensor fan (outdoor unit)?
 
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Old 07-21-13, 05:21 AM
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blower fan,like right now you can walk outside and the out door unit is not running but the blower is on and stays on most of the time. Also my heat pump is a package unit
 
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Old 07-21-13, 08:20 AM
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I had the same issue with my blower fan a few years back. It turned out to be the fan time delay relay. It is a different model than yours but is a Trane heat pump air handler. Here is a link to the part: New RLY02807 RLY02257 Time Delay Relay HVAC Trane | eBay

It may be worth looking at.

These relays have a tendency to stick. If you feed comfortable opening up your air handler there are a few tests you can do. One test you can do is to remove the "G" wire from from your thermostat. I always shut the power off to the system before removing/re-connecting wires on the thermostat to avoid blowing the 5V fuse in the air handler. If the blower shuts off then you probably have a thermostat issue. If it does not shut off then you can open up the air handler. Sometimes you can use the handle end of a plastic screwdriver handle and gently tap the relay a few times and it will unstick the contacts in the relay. You can shut the power off the the air handler and remove the access panel where the relay is located. Then find the green wire and remove it from the terminal marked "T". Then turn the power back on. If the fan stops that probably means the relay is bad. I have attached a photo of my unit so you can get an idea what I am takling about. I am not sure if yours is similar but I believe it uses the same time delay delay.

When I looked up your model number I found this page: American Standard Trane Time Delay RLY03081

It shows a different part number but the cross reference shows RLY02807.
 

Last edited by firedawgsatx; 07-21-13 at 09:20 AM.
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Old 07-21-13, 01:27 PM
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OK I did both tests that you recommended. I turned the power off and removed the green wire then turned the system back on. The fan did not come on. I reconnected the green wire and it came back on. I also set the temperature on the thermostat to the same temp as the inside of the house and the compressor fan turned off like it was supposed to but the fan never did. I think there is a time delay for the supply fan to wait for before it turns off but it never did. I even tapped the relay like you said and it still ran. According to what you said earlier it might be a thermostat issue
 
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Old 07-21-13, 02:34 PM
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As a rule of thumb, if you remove the green wire from it's terminal on the thermostat and the fan turns off it is a thermostat problem and if the fan keeps running with the green wire removed from the thermostat the time delay relay is defective.

You stated in your opening explanation that your fan problem may have started when you installed a Vision Pro 8000 thermostat. Are you sure the wires were connected to the proper terminals on the thermostat? Did you go into the installer's menu and properly configure the thermostat to operate your system, for option 170 you would need to enter the number 1-12 depending on your system. If possible could you post a list of how your wires are connected to your thermostat or even better submit a photo?

I just had another thought. Do you have the thermostat programmed to run different programs throughout the day. If so, are all the programs set up to be on "auto-fan" or could they possibly be in the "on" or "re-circulating" mode? That could cause what you are experiencing. Check to see if your fan is set to "auto-fan". If not, that could be your problem.

The Honeywell RTH221B thermostat is not made to work with your system.
 

Last edited by firedawgsatx; 07-21-13 at 05:15 PM.
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Old 07-21-13, 05:18 PM
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Regardless of the system type that the thermostat is set for G controls the fan. You have a failed blower relay in the thermostat. You should replace the thermostat. The VP 8000 has a 5 year warranty. However it is a professional thermostat and can only be warranted through a contractor.
 
 

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