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jools 08-04-2011 05:08 PM

Blower fan wont come on
I have a Carrier furnace Model FV4B electric heat pump and AC unit. The unit is 3 years old. Today, all of a sudden, the fan stopped running. The unit outside continues to run, and the thermostat says that it's running, but the fan just isn't going. I've replaced the batteries and reset the thermostat. I checked the 5A automotive type fuse on the board inside the furnace, and I've spun the blower fan by hand. It all checks out. Also, after checking the troubleshoting section in the owners manual for the thermostat, I checked the Y terminal in the furnace and there is a 24VAC present. Is there anything else I can check before I get a technician in to take over? Thanks in advance.

Technow 08-04-2011 05:27 PM

that unit has a variable speed motor and requires a good tech to take care of it. If the airhandler has highvoltage and low voltage like you already checked, thats about all you can do.

gregzoll 08-04-2011 05:32 PM

- If motor is hard to turn manually, but turns freely, replace module.
- If motor does not run, check the components listed below according to their instructions.
- If motor runs in some operation modes and not in others, check for a good ground connection between motor ground lead and circuit board
screw marked "ground screw" and check the room thermostat and wiring harness according to instructions listed in Table 4.
- If motor does not stop running, remove the 7-pin plug from circuit board. If motor continues to run, replace motor. If motor stops running
after 2 minutes, it is either the circuit board or thermostat causing the problem. Test whether thermostat is at fault by disconnecting it from the
- Check 5-amp fuse.
- Check for 230v between terminals M1 and M2. If no voltage is present, check power to board. 230-v power enters the board through the black
and yellow lead in the 12-pin plug.
- Check for 24v between SEC1 and SEC2. If no voltage is present, check the transformer.
- Check for burn traces or burnt components. If burn spots are present, replace board.

yuri 08-04-2011 05:49 PM

should have at least 5 yr warranty on the motor and probably 10 so don't mess with it. call a Carrier tech.

jools 08-04-2011 07:53 PM

My PCB is slightly diferent from the one detailed in the manual you attached. But still a great help! I've checked everything up to the PCB, including transformers, and it all seems good. I've also tried jumping the R and G terminals at the thermostat to try and start the fan manually, but it's not coming on. I guess I'd better get a tech in...

jools 08-04-2011 07:57 PM

I'm not sure if this pertains or not, but I've been turning the AC off and on throughout this testing process via the thermostat, the "COOL ON" will flash for about 90 seconds whenever I turn the unit back on, it never used to do that... The compressor outside will not turn on until the flashing has stopped.

gregzoll 08-04-2011 08:11 PM

What is the model & manufacturer of the thermostat?

jools 08-04-2011 08:12 PM

Also Carrier, Model TSTATCCN(HP)01-C

hvac122 08-04-2011 09:29 PM

Sounds like the thermostat has a time delay to stop short cycling.

jools 08-04-2011 09:30 PM

So once it stops flashing, everything should function normally (When the unit is working properly anyway...)?

gregzoll 08-04-2011 09:56 PM

Usually is a four minute delay.

jools 08-04-2011 09:59 PM

Yeah it does stop flashing after a bit, but could this be related to the fan issue? Even after it stops flashing, I still can't get the blower to run up.

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