Goodman GSC90904cxa 93% furnace.

Has 4 flash code. I can't locate a service manual for it.

I get 2 clicks (relays) then inducer fan runs gets the 4 flash code and only the blower fan runs.
I have checked the limit switches, (all that I can locate) three on the burners and 1 on the front of the fire box. They all check out OK and so do the 2 pressure switches. I think there must be another but I can't locate it, was hoping for a manual that I could read the location of.
Thermostat is good, gas is good, filters changed, flue checked, drain lines checked. What am I missing?
Checked via voltage and continuity.
Thanks for the help. I am guessing it could be a control board even though I checked it the best that I could. Has voltage in and out, and transformer is good.

 

There should be a wiring diagram and list of fault codes on the back of the blower door.
Four flash and the blower running indicates an open high limit.

The manuals are just a guide. There could be more or fewer limit switches as shown.
GSC9 manual - pdf

 

Thanks, there were 2 other aux limits on the blower, everything checks out, put on a new board and have the same problem, high limit error. I just don't get it. must be a Ghost!
no power to the igniter! board clicks red light comes on inducer blower comes on.... that's it! then... never power to igniter . unit shuts down except for main blower motor.

2 pressure switches checked, 5 limit switches checked, drain and filters checked, connectors checked, flame sensor checked, new board installed.

Any ideas are welcomed!

 

Post the model number of the board for me.

 

50A55-289 original board
50A55-743 replacement board

 

There are three limit switches. Two appear to need to be manually reset.
You need to have 0v from pin 1 to pin 7 on the 12 pin acc. connector.

This is the loop that causes the four flash fault.

 

Thanks, I got 0v but I giving up for the evening. I am thinking now that I may have a bad induction motor as it is started to squeal a bit as well.

Thank for the help.

 

Your welcome. I'll be here.

 

Thank you for your help. Here is the update.

It was the limit switches on the blower (which you can not get to without removing the blower unit) They are supposed to be aux limits with auto reset. However these were not, they were actually roll out switches manual reset from the factory! Really!
Got them reset and all all is well, I did need to get someone with long arms to get them. Next time will just cut the wires and tie them to get to bypass them. What good are they anyway? LOL


Thanks again

 

You should not remove limit switches. You'll find out what they are good for when your furnace blows up.

Instead of using auto reset type limit switches.... they have chosen to use the manual reset type so that YOU know there is a problem and can address it. You had a manual trip limit switch open. That means your furnace has experienced a high heat situation. That's what needs to be addressed.

Excessive dust, dirty blower wheel, dirt filter, blocked returns, closed down registers.
Many things can cause an airflow restriction that will increase operating heat.