I thought that I would post here after being a long time reader on these forums.
Last night we turned on the heat at the thermostat, and noticed the house colder after a hour.
Thermostat indicated heating, but nothing coming out the vent.
Furnace diag indicator light showed 3 flashes - low fire pressure switch.
There was no vacuum across the switch because the inducer motor was not running. I checked for voltage at the motor and at the PCB output for both high and low 120v. Nothing. Checked the 120v side of the transformer mounted at the bottom of the controller board. There was 120v there.
When I flip the switch to allow power to the furnace, I hear a single click from the controller board area. Is the the relay attempting to close? Or maybe closing and opening again. Would there be a diode between the relay and inducer motor?
I'm uncertain as to how to check for a defective relay without a bypass point.
The unit is 7 years old and has been cleaned every year. Goodman is not honoring the 10 year warranty they promised because they said that they never received the warranty card that WAS sent in. We purchased the Goodman furnace and Rheem tankless at the same time. Rheem apparently received the registration and has since honored their warranty, Goodman conveniently did not.

Is there anything else that I can check for before buying a replacement board?
Are relays a common fault on furnace controller boards?

If it was gas valves or burners, I wouldn't touch it, but a PCB replacement seems simple enough if that's indeed what it is. As long as I match up the DIP switches.
The furnace is a GMV95 and the PCB is a PCBBF106 that has been succeeded by a PCBBF107S.
Local installer quoted me $700 parts and labour. Whirlpool has the replacement board for $160.

I like to learn, but also like to save money where I can.

Thanks in advance...

B

 

You shouldn't necessarily need to register the unit to get parts warranty unless stated in the warranty.



If you jumper r and w1 it should output power to the inducer for low. jumper r and w2 and it should energize high.

The furnace may run the inducer on high for light off with just w1 energized.

At the end of the day if the board is getting a call for heat, proper voltage and polarity but not outputting power to the inducer the board it bad. don't do component level repairs. the board controls vital safeties and it's not worth the risk since it could have damaged traces or chips.

check connections carefully.

The inducer wire is probably on a molex connector; otherwise it would be easy to check the motor.

 

for the gmv i would only get an oem board.

$160 is too good to be true for this furnace.

 

You didn't post the full model number but this manual should cover your furnace....
gmvc950704cx.pdf

In the picture is the 5 pin connector. I marked black, red and white on the plug. That's where the draft inducer plugs in. Check the solder on that connector.

 

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I agree ----replace the while circuit board rather than a part on the circuit board.

 

I decided to order a PCBBF107S that is stated by the manufacturer to be a replacement for the discontinued PCCBF106.
I purchased it here, with a two year warranty:
PCBBF107S by GOODMAN - Buy or Repair at Radwell - Radwell.com
I did see a Goodman manual on changing the older 106 for the newer 107s and the jumper comparisons.
If the molex connector had a bad solder joint, wouldn't the 120v arc and current would flow anyways? As an IT guy, I've seen an ethernet cable carrying 24v loose in the jack it was connected to, the system on the other side was receiving power from two pins, but not data.
If I was going to test the ID motor directly, would I connect neutral and high side to a 120 15A line?
Make no mistake, my question in the first post about checking the relay was simply to be 100% certain that it was a faulty board. I wouldn't attempt to perform a component level repair on a board that is responsible for controlling ignition. It wouldn't save me any time as I would have to order a relay, and the risk to cost savings isn't worth it.

I'm in Canada, and have seem to caught a break in the weather; the next week is supposed to be warm, mild in the nights, and the board should be arriving Tuesday. At least it didn't die during a -40 deep freeze.

The model # is GMV950704CXBB

Should I be looking at replacing the dedicated 15A breaker with a surge protection one to prevent premature component death?? Once in a while we have the power go out, and I haven't been so lucky. Last year the power coming back on fried the relay in my fridge, causing the compressor to continuously run. I changed the relay, only to have the compressor die a week later. The AC power to the furnace comes from a dedicated 15A breaker to a regular shutoff switch located behind the furnace, then to the unit itself.
I have my tankless on a UPS mainly for the surge protection.

Thanks,

Brad

 

The inducer will have 3 leads - neutral and two hots for each speed.

in most motors u only energize one speed lead at a time, otherwise u burn the motor out.

check schematic to see which is low vs high.

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Since it sounds like your area is prone to power quality issues, it would be wise to invest in a whole house surge protector.

Your furnace may have it's own surge arresting components in it, but it's loaded with electronics. the end bell of the ecm motor has a board in it and after warranty is very expensive to change.

the surge protector is good insurance.

i never heard of surge protecting breakers, only the whole house one mike holmes used to love advertizing/pushing on his tv show.

 

I left you a picture where you could check voltage. White is neutral and red and black are the hot wires. One is high and one is low. Doesn't make a difference which is is which.... check them both. There are two possibly three relays on that board that control the inducer motor.

More than likely.... a relay is defective.

 

I changed the board today, being sure to configure the DIP switches correctly based on the old board and the installation manual for the furnace.
It fired right up!
I left the panel off while I flicked the switch and heard the relays click on the board, then the draft inducer kicked into high speed. Then it slowed down and the ignitor glowed for a bit, then the gas valve opened, fired up, followed by the circulation fan a minute later.
Looking at the old board closely, I see the Zettler relay closest to the 5 pin inducer/ignitor relay has soot marks at it's base.

I like learning!!!

Brad

 

Good job.

Got a/c? don't assume the dip switches were set up right from the factory.

Some switch settings are not set in stone like upstage timer with a single stage t-stat. ac fan speed factory setting may not be right.