Air Handler won't shut off, tried everything

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  #1  
Old 01-12-19, 01:00 AM
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Air Handler won't shut off, tried everything

My AC's air handler fan will not turn off. Even when the thermostat and fan are both off. Troubleshooting so far:
outside unit turned off at breaker, fan still runs
outside unit, replaced start capacitor, fan still runs
disconnected all the wires running from air handler to outside unit, fan still runs
bought a brand new OEM fan control board, wired it up exactly like the old one, DIP settings the same, fan still runs
replaced the thermostat on the wall, turned EVERYTHING off, fan still runs
disconnect green wire from wall thermostat (fan control), fan still runs
the only thing that will stop the fan is throwing the breaker for the air handler
Any ideas? Thanks.
 
  #2  
Old 01-12-19, 01:31 AM
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Is this an A/C only system ? Heat pump ? Gas furnace and split A/C ?
Inside unit...... make and model.
 
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Old 01-16-19, 08:34 AM
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Model EVB2400B1

Not sure what brand. Electric AC air handler. Looks fairly simple inside, replaced the fan control board w OEM new board. Havenít replaced the L165-40F limit control or the CRR9-5 Warren rectifier. Could it be one of these two parts? Replacing thermostat didnít work. Disconnecting all 5 wires from air handler to outside unit didnít work. Removing the GREEN wire from thermostat to control board didnít work. Thanks for your help!
 
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Old 01-16-19, 09:44 AM
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Random thought if it is Goodman system: Is there a purple wire attached to the CRR9 ? If so try disconnecting (with power off) and see if blower stops.
 
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Old 01-16-19, 10:11 AM
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Yes it has a purple wire.

Three back wires attached to top, orange and purple attached to base that CRR9-5 plug in to. I will have to try that. What do you suspect if disconnecting purple works? Thanks.
 
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Old 01-16-19, 10:24 AM
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Model is EBV2400B1. Had the B and V switched.

Model is EBV2400B1. Had it wrong earlier. I think it may be Carrier.
 
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Old 01-16-19, 11:05 AM
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See if you can post a picture. Whenever the heat strips are on they are supposed to trigger the air handler's fan. Goodman uses purple to drive this. I see the number you posted and is ICP brand. I was off on a tangent but they all do the same thing.

What was the part number of the control board you replaced?
 

Last edited by Astuff; 01-16-19 at 12:11 PM.
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Old 01-16-19, 11:18 AM
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HK61EA008 is the control board.

Bought a brand new OEM board, set DIP switches the same and wired it up the same. Didnít stop the fan from running constantly. Yes, on the other question, it is a Warren CRR9-5 rectifier and I see a Warren label inside the handler.
 
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Old 01-16-19, 12:26 PM
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See what happens when you disconnect the wire going to NC on the control board's black relay. That will tell whether it is control or heater related.
 
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Old 01-16-19, 05:23 PM
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Your approach to fixing problem is hit or miss which is frustrating and can be expensive, especially if you don't fix the problem. You must have some documentation for the appliance as you provided part numbers for some of the items you have changed. If you have a multimeter (and know how to use it) and a schematic (that you can attach in a poet) I can help you.
 
 

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