Central Air fan not Autostart on heat or cool - but yes with a manual spin


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Old 10-08-12, 08:01 AM
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Question Central Air fan not Autostart on heat or cool - but yes with a manual spin

For a while I have left my fan on 24/7 as whenever it stops , it will not start again unless I go and manually spin the blade to get it moving. All other functions work fine - Heater works when cold, Cooler works when hot.
Basically the process that starts the fan seems to need an extra bit of power , just to get started rotating, but once started runs. The problem is my electric bill is now too much , and I really should find the problem and fix it. I did buy a new controller board - but no difference, so think it may be something that gives the initial inertia to the fan motor to start it spinning, but I don't know what to look for. Unit is probably 15+ years old - Been here since I have been.What could I provide to help determine the cause?
Thaks in appreciation
 
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Old 10-08-12, 04:15 PM
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An update on terminology - The fan I understand is the Main Blower Motor in a horizontal furnace (Consolidated Industries - Model DSA 054 NH3R) - It has in the diagram 5 wires coming out of the motor, but only 3 appear to be used - Heat (which there appear to be 3 (Low/Red, ML/Yellow, MH/Blue ) - Cool (HI/Black) and Neutral (Neu/White) . The 3 are connected to the circuit board in designated tabs, and the 2 extra heat ones (MH and LO) have tabs on the circuit board that say (unused) .
The Circuit Board (Old one - Honeywell ST9141A1002 - New Replacement (Universal-ST9120U) ) -
Basically the motor is variable speed, but only sits on one speed for hot and one speed for cool. In the Diagram I see a Capacitor - But currently I cannot locate where that is on the unit and is that something I can test or check out (I am thinking this may be the problem - but my electronics skills are not that great)
 

Last edited by Charkra; 10-08-12 at 04:19 PM. Reason: Spellings
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Old 10-08-12, 04:40 PM
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replace your capacitor.........
 
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Old 10-10-12, 07:13 AM
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Thanks - I will work on finding it and replacing - Thanks for the response.
 
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Old 11-01-12, 11:10 AM
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Thumbs up Thanks

Managed to find the Capacitor and removed it, Ordered a replacement part which cost < $20 - Replaced the part and put all back together without any issue. Voila! cool air and heated air when I need it now - all works well. ..... My thoughts were - I could have saved myself 100's of dollars if I had done this earlier (like a year ago). So for 1 year I had the motor running 24/7....

Thanks for this Web site and especially the people on it who help others.
 
 

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