[jimmymm]

I just moved into a home built in 2006 with a Goodman CHPF4860D6AA furnace. All worked fine during the first month, but as luck would have it she no longer fires up and provides the heat we so much love this time of year.

Here's what I know so far:

• When the thermostat kicks on, the inducer turns on and I feel air blowing to the burners.
• I never hear the 'click', telling me the gas is flowing. I also don't smell any gas. (The gas water heater and gas stove are working normally).
• The ignitor never starts, or at least it never starts to glow like other furnaces I've seen.
• I attempted to light the burners with a lighter, but there was no gas to light.
• The inducer doesn't ever seem to stop. I was expecting it to shut off after a few failed attempts, but I hung around in the attic for at least 5 minutes and it never shut off.
• The blower turns on and off as expected when switching the thermostat to Fan only.

After much searching online, I've come to the conclusion that I may have a faulty control board, but wanted to make sure I didn't overlook something simple before calling a professional. Before giving up my DIY card, what other things should I test to help identify the problem?

Thanks!

 

[Jnaas2]

Is there a circuit board with a light flashing, If it is does it say on the door what the code reads. There may be a safety open

 

[roughneck]

Probably a safety open. Most likely has an active diagnostic code on the control board.

 

[jimmymm]

Solid light only. I think the label states D1 or DS1.

 

[roughneck]

So there are no codes being displayed after a failed ignition attempt? Is there voltage being sent to the gas valve?

 

[supers05]

There's a couple of safety switches next to the board. (the round things with 2 wires on them) Check for voltage across them, if near 0, then with one probe on one wire, touch the other probe to ground. Report your findings.

You'll need a DMM in voltage AC mode.

Sent from my SM-G870W using Tapatalk

 

[jimmymm]

I was finally able to find my DVM after digging through the remaining unpacked boxes from the move. Thanks for your patience.

1. The leads on the gas valve measure zero volts.
2. The safety switch nearest the gas valve shows 0 volts when attaching leads to both sides of the switch. However, when grounding one lead, each side of the switch measures 27 volts.
3. The safety switch mounted on the blower housing reads zero volts in all tests.
4. The board is now flashing 3 times.

 

[roughneck]

What's 3 flashes mean on the diagnostic chart on the unit?

 

[jimmymm]

"Three flashes indicate pressure switch is not closed, but the induced draft blower is operating."

I checked the hose between the pressure switch and inducer, but it's clean and not-pinched.

 

[roughneck]

Is the pressure switch open or closed during inducer operation?

 

[sktn77a]

You should hear the pressure switch click when the inducer motor is on for a second or so. Try sucking on the vacuum tube - if you don't the switch click, the switch is bad.

 

[crabjoe]

Pull the inducer motor and check it. I had something similar and found a dead bird in the motor of a York Furnace. The bird kept the fan from spinning, but the motor was running.. Could also be a blockage in the venting.

 

[ben's plumbing]

check hose from inducer to pressure switch....check small port on inducer where hose connects insert a small drill bit by hand..and check exhaust pipe for blockage..

 

[KnowItAll]

If something is blocking the exhaust while the enducer is running, it will not allow the furnace to ignite.