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BillyHvac, Journeyman HVAC Tech
Category: HVAC
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Goodman Furnace blinks 3 times and inducer motor not working, help!

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My Goodman Furnace does not start up. LED light blinks three times. Draft Inducer motor does not start, however. I tried jumping both pressure switches in the correct order and got the system to operate normally.All drainage and pressure hoses are open and clear. I believe, then, that the draft inducer motor is faulty. Is this correct?

Billy : Hello, First make sure the barbed fittings are also cleared that the tube attaches to...also make sure the vent pipe and intake pipe (if equipped) are clear. You may also want to remove the draft motor and make sure no straw, grass feathers etc are in blower wheel which cuts down on suction....

JACUSTOMER-i4imm0pd- :

I have inspected those fittings, they seem clear. Though I could take the motor off.

My most immediate concern, though, is that the motor doesn't even seem to WANT to start up.

Billy : Ok..I missed the "not" in inducer does not start....sorry.
Does it hum or get warm?

JACUSTOMER-i4imm0pd- :

That's, when the call for heat is relayed to the furnace, I can hear a "click" which I assume is the circuit board telling the motor to begin running. Nothing happens at that point, and the red light then flashes three times.

Billy :

Thank have a meter to check voltage? And have you felt the motor to see if its humming or is getting warm. And is this first time starting this year?

JACUSTOMER-i4imm0pd- :

It definitely does not hum, let me check to see if warm. No, I don't have a volt meter, and yes, this would be the first time starting this year.

Billy :

Ok....sometimes, not always...the motor is seized from setting.....Here is what I would try...turn power off and remove the motor assembly. Make sure the blower wheel is clear of animals etc. then, spin it a couple times. If can assemble in your hand and just "bump start" the unit with the power switch and see if fan spins.

JACUSTOMER-i4imm0pd- :

Fair enough, I will try that. By the way, the motor is not warm. It is cool / room temperature to the touch.

Billy :

If possible. You could get a cheap 2 wire 120v tester and see if the plug that goes to the motor has 120v

JACUSTOMER-i4imm0pd- :

OK, the motor is not warm or humming, and the fan is not obstructed. The fan actually spun quite easily by hand when I did that, but does not fire up when connected back to the furnace. I "jiggled" the wiring connections and it still does not start up. I will get a 120v tester this afternoon and let you know about that.

Billy : Excellent...that will be the deciding factor. I wish you luck!

JACUSTOMER-i4imm0pd- :

Hi, again - I can't tell if the motor has 120v or not - when I hook the multimeter up and turn on the furnace, the reading spikes for a second (to as much as 80 or so) and then goes back down to 0. Does that sound right? Just want to be sure I was using the meter correctly.

Billy : Do you have set for volts ac with ~ac voltage symbol and a value of 200 or less. I just want to make sure we pick between the inducer motor or circuit board correctly. You can test the meter by testing a working outlet for 120v

JACUSTOMER-i4imm0pd- :

Yes, the meter is set to ~ac @ 200 (lowest it goes). Just tried it again for good measure and it spikes between 17 and 80 and then goes back to 0. Tried the meter on a working outlet and it always stays at zero.

Billy : So on a working outlet you do not get 120v? Let’s try it on L1 and COM on the circuit board with door switch taped down and power on

JACUSTOMER-i4imm0pd- :

My apologies - I had the meter configured incorrectly. I just tested on the wall outlet and got 120.7v. Tried again on the motor connection and it does the same - spikes up to 80 or so (sometimes lower) and then back to 0.

JACUSTOMER-i4imm0pd- :

I looked at the circuit board and couldn't determine exactly where to connect the meter, so I tried a mix of locations of inbound / outbound wires (the ones colored white, yellow, green, etc). Seems most read about 70v, with the occasional one reading 0.

Billy : are you familiar with the thermostat wire connections? R, Y, W, G and C

JACUSTOMER-i4imm0pd- : Yes, for what it's worth, mine only has R,Y,G,and W.

Billy : Yes, then you have a blue wire I believe that attaches to a wire from outdoor ac unit

JACUSTOMER-i4imm0pd- : Yep

Billy : That is "common" we need to see what the voltage is from "common" to R

JACUSTOMER-i4imm0pd- : At the thermostat? At the circuit board in furnace

JACUSTOMER-i4imm0pd- :

Oddly enough the blue wire in the furnace isn't connected to anything...and it doesn't look like it ever was. The sheathing is still completely on it (never been stripped) and it's twisted around itself.

Billy : No air condition?

JACUSTOMER-i4imm0pd- : No, we have A/C, and I just tested it again to be sure. It works fine.

JACUSTOMER-i4imm0pd- : All the connections at the furnace (where the wires come onto the circuit board) measure right about 70v, with the exception of any of them connected to Yellow, which only measures about 27v.

Billy : Thank you.....I am not trying to waste your time....I just want to be sure....there is a hot wire that comes into the furnace and goes to the door safety switch, and then leaves door safety switch and attaches to the circuit board. Do you know what I refer to?

JACUSTOMER-i4imm0pd- : No, believe me, at this point I'm worried about wasting YOUR time! And yes, I can see that wire.

Billy : Put one meter lead to that wire...and the other meter lead to ground..or metal cabinet...tell me what we read

JACUSTOMER-i4imm0pd- : 121.9v

Billy : unplug the plug to inducer and do the best you can to see what the power is when inducer is to start. Power to the inducer

JACUSTOMER-i4imm0pd- :

Ok, here's what I got: there are two wires leading to the inducer. One is black/gray, one is white. There is also a green (ground, I assume) leading from the inducer to the metal wall of the furnace. The black and white wires each have a connector mid-wire. I separated the connector for black and tested it with the furnace on. It reads 0v. Then put back the black wire and did the same with the white. It also reads 0v. By chance are we moving toward a problem with the control board?

Billy : You are correct.....If there is 24v present at W terminal where the white thermostat wire attaches....and anything short of 115v going to inducer motor, then we have a bad circuit board. It was kind of my hunch but I hate to see a couple hundred spent on a new motor and still not work...
It appears to be a bad circuit board. I do not know how much tinkering you are comfortable with...but if you want to get 120v to the inducer..either with ext cord or from can test the motor...It can also be benched tested by removing and wiring to 120v to see if it runs....but at this point I find it safe to say the circuit board is bad

JACUSTOMER-i4imm0pd- : ah, very good. I am fine tinkering - just one quick confirmation, though: exactly which connection would I make to test the motor? from the safety switch to the motor, then?

Billy : now you got it...yep....

JACUSTOMER-i4imm0pd- : perfect, hey thanks so much for your help!

Billy : You are very welcome...if you need further help let me know.

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