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Phil
Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 5648
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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Indoor blower not working

Customer Question

indoor blower not working
Submitted: 10 months ago.
Category: HVAC
Expert:  Tim H. replied 10 months ago.

Hi, I'm Tim and I'm an HVAC expert here to assist you with your questions. Please provide all information I request as it makes it more difficult to troubleshoot something when I'm not there onsite. Essentially, you become my eyes and ears. Thanks for the opportunity to help. At the end of our dialog, you will have a chance to rate my service, but please wait until we are finished and you're satisfied you have all the information you need. Please be patient as many times we work with several customers at once.

I understand you are having blower issues. Can I get more information such as furnace make and full model number? What checks have you done yourself so far?

Customer: replied 10 months ago.
it is a Carrier model #: Fx4DNF087T00. I tried turning on the heat an the cooling with the fan set to ON not AUTO, and the blower inside of the indoor unit (upstairs if that matters) will not turn on. The cooling system is running (i.e. it gets cold, it froze over when I let it run too long) but the blower will not run
Expert:  Tim H. replied 10 months ago.

Does the blower wheel turn freely if you reach in and spin it with power off?

Customer: replied 10 months ago.
with the thermostat turned on I tried forcibly turning the blower and it would turn while I rotated it but it would not continue turning
Customer: replied 10 months ago.
I checked the safe switch (the one that prevents it from running if the condensation cannot escape), but it was dry. I suctioned out the condensation output pipes outside, and I checked the voltage running from the red line to the ground in the thermostat and it was about 24 V
Customer: replied 10 months ago.
The filter is reasonably new, it has a little bit of dust but even with the filter removed the fan does not come on
Expert:  Tim H. replied 10 months ago.

Is this a standard blower or ECM?

Customer: replied 10 months ago.
whats ECM?
Customer: replied 10 months ago.
I dont know
Expert:  Tim H. replied 10 months ago.

It is a different kind of blower, slightly larger in size than a standard blower and it has smaller wires.

Customer: replied 10 months ago.
I think it is standard
Customer: replied 10 months ago.
the blower is about the size of a basketball and the wires are normal sized wires
Expert:  Tim H. replied 10 months ago.

If it's a standard blower, it is either a bad board or a bad motor and is confirmed by measuring voltage

Customer: replied 10 months ago.
ok
Customer: replied 10 months ago.
I have a multimeter
Expert:  Tim H. replied 10 months ago.

A picture would help me determine type of blower you have if you could upload one.

Customer: replied 10 months ago.
will do, hold on
Customer: replied 10 months ago.
attached
Customer: replied 10 months ago.
I also don't see a circuit board, just the wires and connectors at the top of the picture
Expert:  Tim H. replied 10 months ago.

That looks like an ECM motor. Troubleshooting these is much more complex, but on pages 10.11, and 12 of this manual it walk you through some things to check. If you want to troubleshoot yourself, I recommend going through these checks.

Expert:  Tim H. replied 10 months ago.

http://dms.hvacpartners.com/docs/1009/public/0c/sm-fancoil-05.pdf

Expert:  Tim H. replied 10 months ago.

Specifically a section : Motor will not start

Customer: replied 10 months ago.
it looks like they're saying I should remove all of the wires from the thermostat and check each one individually
Expert:  Tim H. replied 10 months ago.

Not seeing anything about the thermostat. But it does start out with checking all molex connections and checking the 5 amp fuse.

Customer: replied 10 months ago.
The fuse looks like the connection in the middle is still complete and I pushed the connectors in so I think they are not the issue. The part I was looking at is halfway down the page on the right side of p. 11
Expert:  Tim H. replied 10 months ago.

Start here:

Customer: replied 10 months ago.
that's what I was talking about. I looked at the fuse and it looks intact, and I checked the connectors to make sure they are seated
Expert:  Tim H. replied 10 months ago.

OK, well you need to go through all the checks they indicate to troubleshoot. This may take a while.

Expert:  Tim H. replied 10 months ago.

I have to leave for a bit, but will check back later.

Customer: replied 10 months ago.
how do i end the conversation?
Customer: replied 10 months ago.
it won't let me end the conversation so I'm assuming that means that you need to do it. So could you please conclude the conversation, I do not want to take it any further.