Goodman furnace with 4 flashes
#1
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Goodman furnace with 4 flashes
I have a Goodman GKS90703BXAD, i got the same 4 blinks. We called a contractor to look at it. They want $549 to replace the high limit switch and more than $3,000 to replace ignitor, flame sensor, and some pressure switch. I thought it was very expensive. I Google around and found this site and do some troubleshooting myself. I bought the High Limit switch and other maintenance items Ignitor and Flame sensor. The total parts cost me $40 and replace the parts in 15mins. However, the fire still did not start. I started checking the main control board and saw the 2A switch. I pulled it out and inspected and it was not broken. I noticed there were dust particles around the fuse socket. I dust it off, plugged it back in, and the Flame started and no more 4 blinks.
I took out the old High Limit Switch and checked for continuity. It was good. The technician was wrong to begin with, he was just based on the diagnostic light to give us the proposal. I was glad I did a second look. This lesson taught me
Never trust a technician on the 1st one you call and never go with the 1st proposal
Do some home work yourself before calling the technician
I bought all the parts from the web site BUY GOODMAN REPLACEMENT PARTS or SuppliesDepot https://www.suppliesdepot.com Very helpful, honest, right on the spot with the parts I need.
hc
Separated from... http://www.doityourself.com/forum/ga...it-switch.html
I took out the old High Limit Switch and checked for continuity. It was good. The technician was wrong to begin with, he was just based on the diagnostic light to give us the proposal. I was glad I did a second look. This lesson taught me
Never trust a technician on the 1st one you call and never go with the 1st proposal
Do some home work yourself before calling the technician
I bought all the parts from the web site BUY GOODMAN REPLACEMENT PARTS or SuppliesDepot https://www.suppliesdepot.com Very helpful, honest, right on the spot with the parts I need.
hc
Separated from... http://www.doityourself.com/forum/ga...it-switch.html
Last edited by PJmax; 12-12-16 at 01:02 PM. Reason: Removed company bash/started new thread
#2
Welcome to the forums.
This isn't Angies list. We don't discuss contractors. We don't list them or belittle them.
Since there are so many online parts companies I will rarely list or suggest one.
I'm guessing the quote you were given was over the phone.
I doubt dust around the 2A fuse was the problem. You may have an intermittent problem that will be back.
This isn't Angies list. We don't discuss contractors. We don't list them or belittle them.
Since there are so many online parts companies I will rarely list or suggest one.
I'm guessing the quote you were given was over the phone.
I doubt dust around the 2A fuse was the problem. You may have an intermittent problem that will be back.
#3
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Thank you. Sorry about that. The repair quote I received was from on-site diagnostic. You are right, the problem came back tonight, i reseated the fuse and the flame started again with no flashes. I might need to try the control board. What do you think?
#5
4 flashes is indeed high limit.
there may be an aux limit.
You have to check the limit for voltage drop when it trips. if you get 24vac across it, it's open and you have to figure out why it's tripping.
the limit is fine, it's doing it's job and preventing the furnace from running in an unsafe manner.
If a circuit breaker is tripping, the circuit is overloaded. The electrical equivalent would be an electrician who changes the breaker due to nuisance tripping, or worse puts a bigger breaker.
The limit will automatically reset when furnace cools down so a good continuity test long after doesn't mean anything.
It's either low airflow, furnace overfired or both.
Open all of your vents.
Check the filter and blower wheel for dirt builtup. If the wheel is dirty the secondary heat exchanger is too.
Clock the gas meter.
Run furnace for 15 minutes and check the temperature rise.
Google search gas meter clocking and temperature rise test.
there may be an aux limit.
You have to check the limit for voltage drop when it trips. if you get 24vac across it, it's open and you have to figure out why it's tripping.
the limit is fine, it's doing it's job and preventing the furnace from running in an unsafe manner.
If a circuit breaker is tripping, the circuit is overloaded. The electrical equivalent would be an electrician who changes the breaker due to nuisance tripping, or worse puts a bigger breaker.

The limit will automatically reset when furnace cools down so a good continuity test long after doesn't mean anything.
It's either low airflow, furnace overfired or both.
Open all of your vents.
Check the filter and blower wheel for dirt builtup. If the wheel is dirty the secondary heat exchanger is too.
Clock the gas meter.
Run furnace for 15 minutes and check the temperature rise.
Google search gas meter clocking and temperature rise test.
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it was 4 flashes, it indicates High Limit Switch issue. The flame did not start last night, i reseat the 3A fuse on the mainboard and it fires up right away. It is blizzard!!! We continue to have heat tonight luckily since Polar Vortex is hitting East coast tonight and tomorrow with temp dropping to 10 degree.
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Thank you for your reply. I think there are 2 AUX Limit switches in front of the burner. I think they are to prevent Flame Roll Up. The blue flame is normal without "roll up". My furnace is only 8 years old, I change air filter every 30-60 days. Blower and all components are clean. I only test continuity on the High Limit Switch and did not test voltage drop. The furnace is still working since I reseat the 3A fuse on the control board last night. It is intermittent. I have to keep observing and check the voltage when/if it happens again.
hc
hc
#8
High limit and rollout are not the same.
High limit stops the furnace from overheating.
The limit will have to trip a few times during a heating cycle for it to lock out.
During shorter heating cycles it may not trip enough for a lockout for happen; if you're by the furnace you may see the burners cycle off and the fan stay on. The furnace will cool down, the burners will start again until the furnace overheats again.
Just because it's heating doesn't mean something isn't wrong.
By removing power from the board, you're resetting it.
If you turn the heat up a few degrees and let it run for a good half hour while watching it, you should catch the problem.
A lot of cycles may be 10 minutes or less while it takes at least that time for the furnace to reach steady state operating temp.
This is not a problem that can be resolved by changing parts. Only checking to see if the furnace is overfired and doing what you can to raise airflow.
Do you have a digital thermometer with a thin stem? that's needed to troubleshoot this problem.
High limit stops the furnace from overheating.
The limit will have to trip a few times during a heating cycle for it to lock out.
During shorter heating cycles it may not trip enough for a lockout for happen; if you're by the furnace you may see the burners cycle off and the fan stay on. The furnace will cool down, the burners will start again until the furnace overheats again.
Just because it's heating doesn't mean something isn't wrong.
By removing power from the board, you're resetting it.
If you turn the heat up a few degrees and let it run for a good half hour while watching it, you should catch the problem.
A lot of cycles may be 10 minutes or less while it takes at least that time for the furnace to reach steady state operating temp.
This is not a problem that can be resolved by changing parts. Only checking to see if the furnace is overfired and doing what you can to raise airflow.
Do you have a digital thermometer with a thin stem? that's needed to troubleshoot this problem.