I've been having sporadic problems with the goodman heating and A/C unit for the past two years. I've had two different companies look at it, each was unable to resolve my issues.

Symptoms:
Getting the four flashes, meaning the "open high limit switch" disposition is "stuck".

If I keep turning it on then off, finally it will go, and the heater will work for a few hours. Then repeat...

Had the switch replaced. I even insisted the second tech go through the procedure of testing it. He took it out, plugged the "voltmeter" thingy (pardon my professionalism) and it made the beeps described in all the videos I've watched on youtube. Indicating the switch is good.

Made sure he checked the "evaporator coil". It looked clean to me.


The second tech said the heater might be "too big" for my condo and not distributing enough air causing it to heat up, and finally fail.

This made sense to me, as my condo is only like 1200sq feet and the heater room is probably about 6"x6". I took the grill off the main air intake (where the the airduct in my condo where that metal piping goes.). As well as propping the door to the heater room open.

This seemed to be working fine for two days. Right as I was planning to get a better grill on the air-intake, widen the intake, and cutting an intake on the door, something new happened.

All of a sudden the heater would not turn on when the thermostat went below the defined threshold. At first i could turn the thermostat on and off, then the heater would start up again, but fail to come on unless the thermostat was cycled.

Tried putting new batteries in the thermostat, to no avail.

The last time it **** off and would not come back on resetting the thermostat did not work.

Looked at the heater and got three blinks, indicating the pressure switch. Cut the power to the heater several times and still got three blinks...

I softly jiggled the circuit board (wondering if there might be short), then boom! Back to four blinks.......

Power cycled heater, and that's where I stand right now.

I don't know much about the terminology a lot of the guys in here use, but would really appreciate some ideas of what to do. I've just come to the conclusion I'm wasting my money trying to find a GOOD Service Tech...


P.S. Merry X-mas!

 

I have seen the same problem before. You can bypass the limit switches but still the circuit board will flash 4 times. Unfortunately, the problem was resolved by replacing the circuit board.

 

Okay, just to add, I don't think "jiggling" the circuit board caused it to switch from three to four blinks. It was a coincidence.

When the heating cycle completed, it did not turn on for the next heating cycle after the thermostat dropped. Went to check the heater and got three blinks then it automigically switched to four blinks. Power-cycled the heater and it finally came on again.

Thanks for the response @ender!

I looked at the cost of a circuit board. While pricey, I hope this is the problem: it will FINALLY be fixed, and I can do that myself..

Still sound like the circuit board?

 

We don't know a whole lot about your installation like age or model number of unit.

There are some things that are common problems:

Check the connections on the control board. Are they clean and tight.
Check the ground to the control board. A ground is extrmely important. There should be a ground wire connection that should be checked out at both ends.

 

Checked. No lose connections, ground is ok.

Looked for the model number: Gos8o7o3axbo

For some reason cannot find that model ANYWHERE. That is the only model number the furnace I could find. Not sure if it was "O" capitol O, or the numeral 0 as in zero. :-\

Now whenever it kicks on, nothing. Just blinks four times and won'y even ignite.

Will post pics to help identify in the afternoon.

 

OK. I've paid for someone to look at this. I've had three different repair guys look at it.
Here's the model number: G0s80703axb0. I'm confused about the model. I cannot find it on google, but that is the only model number on that unit.

The heater was installed in 2005, just out of warranty last September. I do not understand why nobody (not on the boards but service people I am paying) can fix this. Here's what it is doing now:

will shut off 3 blinks.
if I powercycle the heater it will come on and blink three times.
if I pull the wiring harness while the power is off it will do one of two things:
ignite then go out and blink 3 times after a second blower kicks in
or -- actually heat for about 5 to 20 minutes then shut off and do three blinks.


Update:

it ran for about 45 minutes once.. Enough to heat from 40 to 70. After that cycle it now gets four blinks no matter what?

Sometimes it will click like its about to ignite, and "dry - fire". Then click again, then go to four blinks. :-\

 

Here's a pic. Tried to edit previous post, but edit function is not working...

http://img543.imageshack.us/img543/1818/img4537b.jpg

 

Here.....try this as the model number GDS80703AX or GDS80703AXBC


If you pull on the wire harness and it intermittently starts working....it's either a bad connection or control board issue.

 

Thanks PJ!

I looked at board, and it's a White & Rodgers, and is fairly expensive (considering a I can get decent computer MoBo for less), but might be under warranty.

Can someone explain, in laymen's terms, how to "jump" or bypass, the high limit switch? I want test it as well (just to make sure).

I understand what it does. I've read "just touch the two wires together", but mine have little metal ends covered in plastic and don't look like that would work. Also, I just want to make double sure, before I go and start touching various wires together. :-\

 

Just to update this thread for those that might find it through Google. A new circuit board fixed the problems.

 

Thanks for the update.......