New furnace fan motor not working


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Old 07-07-15, 09:55 PM
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New furnace fan motor not working

I've just replaced my furnace (Trane TS80) fan motor and capacitor.
(old: AO Smith DL1056, new: Century, 4KA36, fan motor)

Part of my problem is that a heating and air conditioning repairman took out my old motor before I could get snapshots of the wiring... The motor he put in had somewhat different wiring and was also noisy. He said it was a bad motor!
So, I'm repairing myself.

Control board blinks at regular interval indicating that it's OK.

Compressor comes on but new motor does not.

I'm uncertain about my the connections highlighted in the attached image.

1. the door switch. I have the switch connected to the top terminal (LINE-H) and the transformer connected to the lower terminal (XFMR).
2. the white 24v transformer wire connected to XFMR-N.
3. There's a jumper between humidifier wire and the main neutral wire. I know that one pair is connected to HUM-H but uncertain where the main neutral connects. I have it connected to HUM-N.
(Nothing is connected to CIR-N or LINE-N.)

The four other motor leads are connected as indicated for my specific Trane TS80 model:
connected to capacitor:
brown/white
brown
connected to control board:
red - park
yellow - park
blue - cool
black - heat

Tried another capacitor but same result: no fan
Could my new motor be bad too?!

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Last edited by Mristau; 07-07-15 at 10:14 PM.
  #2  
Old 07-07-15, 10:45 PM
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Your new motor is a 3 speed motor. Move yellow to "Cir N"

Yellow is a 4th speed with many OEM motors that also have white. It is neutral with 3 speed motors when white isn't present.
 
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Old 07-07-15, 11:27 PM
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Well that's probably a good change. Uncertain because I'm getting no power to board. Previously, board LED was flashing, compressor came on. Checked circuit breakers. Fuse on exterior of furnace looks good. Fuse on board replaced. Everything is dead as a door nail.
 
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Old 07-08-15, 05:05 AM
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Is the door switch closed?
Are you waiting over 5 minutes in cool mode?
 
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Old 07-08-15, 07:46 AM
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Door switch is closed. Previously, board lit up, relays clicked and compressor started when door switch closed.

Did not wait over 5 min in cool mode. (This was when yellow was parked.) Will do with yellow at CIR-N once I can solve the everything dead power problem.
 
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Old 07-08-15, 11:48 AM
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Connect neutral to Line N.
 
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Old 07-08-15, 01:32 PM
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Thanks Huston.

Move yellow at CIR-N to LINE-N?
OR
XFMR-N to LINE-N?
 

Last edited by Mristau; 07-08-15 at 01:49 PM. Reason: addition
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Old 07-08-15, 01:41 PM
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Since board is getting no power, should I try replacing 115 to 24v transformer?

REPLACE THIS:
Manufacturer : Basler
Manufacturer# : BE25214001
Product model# : C340041P01

WITH THIS:
WHITE-RODGERS Class 2 Transformer,24VAC,40 VA,1 PH - Class 2 Transformers - 6WU91|90-T40F3 - Grainger Industrial Supply

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Old 07-08-15, 04:03 PM
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Thanks for your help Houston204.

All working now.

White wire from transformer connected to LINE-N and yellow wire from motor connected to CIR-N. Holding door switch for over 5 min. important to do.
 
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Old 07-09-15, 08:59 AM
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Actually, one minor problem remains... Fan runs when thermostat set to AUTO but not ON.
Replaced thermostat but this was also the case with the previous one. What to check?
 
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Old 07-09-15, 09:12 AM
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Make sure that you check the blower motor in heat mode also.
 
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Old 07-09-15, 10:49 AM
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Thanks - fan motor does not come on in HEAT mode...
 
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Old 10-06-15, 03:22 PM
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Help! My furnace has been running fine all summer but now that I need the heat the fan will not come on with thermostat set to fan/on or fan/auto.
(Gas and flame OK but no fan.)
Fan motor wiring is:
Blue - COOL-H
Black - HEAT-H
Red - PARK
Yellow - CIR-N
...image of board here:
https://www.dropbox.com/s/edt157or8b...iring.pdf?dl=0

White-Rodgers, Intel-ignition, 50A65-476
 
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Old 10-06-15, 07:44 PM
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The call for heat starts a delay until the blower comes on in heat speed. When you put the FAN ON switch on..... the board activates the blower immediately on heat speed.

Looking at the picture.... see the terminals circled in pink. When you go to FAN ON mode the HEAT H and the EAC H should measure 120v to any of the neutrals. If you have the 120v then you have a motor problem. If you don't have the 120v then you have a board problem.

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Confirm that the red is actually on a PARK terminal.

FYI.... LINE N, HUM N, EAC N, XFRMR N, and CIR N are all tied to the same neutral. They are interchangeable.
 
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Old 10-06-15, 08:03 PM
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Thanks for your notes on this!

So, voltmeter test from CIR-IN to EAC-H and/or HEAT-H?

(The blower motor DOES work if I put thermostat on Cool/FanOn.)
 
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Old 10-06-15, 08:09 PM
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Red motor wire is PARKed.
A new controller board was installed this July. It's LED flashes at the "I'm OK rate."
 
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Old 10-07-15, 07:02 AM
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Are you waiting until the gas fires up and burns for a little while before the fan should turn on?

I didn't find a ts80 manual but if you have a gas furnace it should be something like this...


" SEQUENCE OF OPERATION Thermostat call for heat R and W thermostat contacts close signaling the control module to run its self-check routine. After the controlmodule has verified that the pressure switch contactsare open and the limit switch(es) contacts are closed,the draft blower will be energized.As the induced draft blower comes up to speed, the pressure switch contacts will close and the ignitor warmup period will begin. The ignitor will heat for approx. 17seconds, then the gas valve is energized to permit gasflow to the burners. The flame sensor confirms that ig-nition has been achieved within the 6 second ignitiontrial period. After the flame sensor confirms that ignition hasbeen achieved, the delay fan ON period (fixed at 45 seconds) begins timing. After the delay of 45 seconds,the indoor blower motor will be energized and will continue to run during the heating cycle."

If this is electric heat or hot water the thermostat needs to be reconfigured.
 
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Old 10-07-15, 07:35 AM
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Yes - Thanks
Leaving burners on for couple minutes (until hearing a rapid clicking)
This unit is gas.
 
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Old 10-07-15, 10:54 AM
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I took my diagnostics from the module manufacturer. When the t'stat is in FAN ON..... the HEAT H is activated...... bypassing any heating demand delay.

Did you check for voltage like I asked ?
 
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Old 10-07-15, 11:58 AM
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Yes - both EAC-H and HEAT-H are reading 120v.
 
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Old 10-07-15, 06:10 PM
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Swap the red and black wires on the control board. You should get blower activation.

If you do.... the black tap on that motor is not working.
 
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Old 10-08-15, 09:21 PM
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Swapping those two wires fixed the problem. Big Thanks
Is there some way to make a donation?!
 
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Old 10-09-15, 12:44 AM
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Keep in mind....

black=high speed
blue=medium speed
red=low speed

It's most common for black to be on A/C H and blue or red on HEAT H. You now have red in the heat position which means the blower is running at low speed. You'll need to make sure in heat mode that the furnace doesn't cycle on high heat.

Since the black wire doesn't work from your motor.... you have a defective motor. Probably bad from the start.
 
 

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