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Phil
Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 8768
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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I have a Broan 21 ECM18electric furnace, and the fan does

Customer Question

I have a Broan 21 ECM18electric furnace, and the fan does not start.
JA: Do you have fuel in the tank? If so, is the shut-off valve open and the fuel clean?
Customer: there is voltage to blue wire pin 3 and input voltage to motor
JA: Do you plan on doing the work yourself?
Customer: hopefully
JA: Anything else we should know to help you best?
Customer: heaters cycle on off, furnace worked fine last fall and then was shut down for winter, when power re-applied it did not start. new control board install. Relay k7 energized putting 24 vac on pin 3 of motor
Submitted: 1 month ago.
Category: HVAC
Customer: replied 1 month ago.
JA what has fuel got to do with an electric furnace, this startment gives me very confused vibs?
Customer: replied 1 month ago.
Posted by JustAnswer at customer's request) Hello. I would like to request the following Expert Service(s) from you: Live Phone Call.
Customer: replied 1 month ago.
Let me know if you need more information, or send me the service offer(s) so we can proceed.
Expert:  Phil replied 1 month ago.

Hello, the confusing vibes were from our automated assistant which did not realize you had an electric furnace, and thought for some reason it was oil fired.

I need a close up exceedingly well focused photo of the wiring diagram glued to the inside of the blower access door on your electric furnace, I will mark it up with some trouble shooting instructions.

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Meantime here is link that covers the ECM motor trouble shooting procedures. You may also want to buy an ECM motor tester that I will link to later.

Click here please

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OPENING STATEMENTS

Important note about RATING my work:

I am a retired mechanical engineer and HVAC/electrical/ refrigeration and boiler contractor ... with 56 years in this business. The last 20 of those years consulting for major firms nationally..

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All I ask is please respect me and my input by selecting the***RATING LINK***at the top of your page, that is the only way I am credited through the site. Rating does not affect your charges nor ability to refund if not satisfied.

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If you need to be coached through a full diagnosis/repair,and wiring etc. for up to two days, and wish to be trained to use test instruments...... that goes well beyond' Just a simple Answer' of course, and goes beyond what most other experts here offer.....rate my simple answer so far positively.. and I will deliver that training and coaching to you All on the same dime so to speak.

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Lacking a positive rating I can spend days helping a person at my own expense and loose my shirt, shorts and socks on the deal.

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Attach a close up photo of the wiring diagram glued to the inside of the blower access door and I will mark it up with trouble shooting instructions then follow up with step by step training and coaching until you have a solution.

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Photo must be exceedingly well focused. Use the 'add files' link next to your send button to get the photo to me.

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Phone call offers:

If you wish to accept the companies $25 phone call offer, if indeed they send you one, this will go a *lot faster, but it IS 100% optional... or we can continue here in this dialog box at no additional charge.

Customer: replied 1 month ago.
I have added a better copy of 21ECM18/20 diagram
Expert:  Phil replied 1 month ago.

Thanks, CLICK HERE PLEASE

beyond that you will need the ECM motor tester, CLICK HERE.

call these people on the phone give them brand and model number of your furnace and tell them you need and ECM motor tester for that furnace Click here

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Its time to locate the 'finish and rate your expert...' link and click on it to be coached through a full diagnosis/repair,and wiring etc. for up to two days, and wish to be trained to use test instruments...... t\

.

That goes well beyond' Just a simple Answer' of course, and goes beyond what most other experts here offer.....rate my simple answer so far positively.. and I will deliver that training and coaching to you All on the same dime so to speak.

Customer: replied 1 month ago.
I measured the voltage between N & G and got 124 volts ac. Between L & N voltage is 240 volts ac. Between L & N voltage is 124 volts ac. Depending on K7 and switch VS, The voltage measured between P1-C (24vac common out) to M Pins 1,2 or 3 voltage is 28 vac.I then opened up the back of the motor to check motor and resistance readings on the three pin connector on the motor are:
Pin 1, Pin 2, Pin 3 to ground are infinite. Reading between Pin 1 & 2, Pin 1 & 3 and Pin 2 & 3 all read 21.3 ohms.
Expert:  Phil replied 1 month ago.

Thanks, ***** ***** proven that there is power to the motor and that the DC three phase motor windings are good. the problem is with the electronic speed signal controls. You need an ECM motor tester that I linked to earlier to diagnose that.