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airheatman, HVAC Technician
Category: HVAC
Satisfied Customers: 8373
Experience:  Furnace, A/C and heat pump specialist.
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I have a brand new goodman furnace, the burner lights and

Customer Question

i have a brand new goodman furnace, the burner lights and produces heat for 5 minutes and then shuts off, once the fan stops, the whole cycle starts again.
JA: Did you double-check the thermostat's settings? And what about the filters?
Customer: tried two different filters and without the filter same result. i have thermostat at 72 and the heat wont get up past 67.
JA: Do you plan on doing the work yourself?
Customer: yes, i installed it myself.
JA: Anything else we should know to help you best?
Customer: everything else seems to be right
Submitted: 9 months ago.
Category: HVAC
Customer: replied 9 months ago.
checked vent flue and condensation trap is full
Expert:  airheatman replied 9 months ago.

Can you give me complete model from inside furnace in burner compartment so I can provide guidance with this specific unit.Model will be on a label just above burners on right or left inside panel

Then look in blower compartment and see if we have a control board with a blinking light.If so tell me the pattern of that flash.That will indicate what is wrong and tell us where to start troubleshooting.

Customer: replied 9 months ago.
gms08....flashing light once burner goes out blinking at 4 blips.
Expert:  airheatman replied 9 months ago.

4 blinks is an open limit error.You may just have a bad limit from factory. Do you know where main limit is?

Expert:  airheatman replied 9 months ago.

For a test, let's unplug wires to limit and connect the wires together ,bypassing limit, and see if furnace will work.

If it does, just replace the limit.If not we will go from here.

Customer: replied 9 months ago.
burner would not work
Expert:  airheatman replied 9 months ago.

Did error code go away?

Customer: replied 9 months ago.
error code the same
Expert:  airheatman replied 9 months ago.

Follow those wires that go to limit and locate every limit in unit doing same thing until you find one that makes the error go away and furnace work.You may have 4 or five

Customer: replied 9 months ago.
wires go directly into board.....just to confirm, the condensation trap should be filled with water, correct?
Expert:  airheatman replied 9 months ago.

1. There should be one wire coming from board going to first limit, out of limit to next limit,out of that one to next until it goes through all limits, then it goes back to board telling board the circuit is closed so unit can work.If any limit in circuit is open the circuit is broke and we get open limit error.

2. Trap should have water but has nothing to do with a limit error.If drain were an issue we would have a pressure switch error not limit.

Customer: replied 9 months ago.
i have gone through all of the connections and reconnected with no luck.i have checked all the returns, exhaust pipes and flue. not sure what it can be, will have to call for service. don't quite understand it because the unit is brand new and just installed.
Expert:  airheatman replied 9 months ago.

Wish we could et it going.If you are getting an pen limit code one of the limits should be pen.Make sure all wires are connected good.Unplug connector n board and make sure al wires are seated and making connection when plugged in.If so an onsite tech is going to be necessary.Should be covered under warranty.

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Customer: replied 9 months ago.
i retried by passing the main limit and the burner is continuing to run....i must have to replace a brand new limit? also, can i continue to run the furnace without the main limit in place until tomorrow?
Expert:  airheatman replied 9 months ago.

I can not tell you to bypass and leave due to liability reasons.Not unusual to have a bad part although new as most of these parts come from China or Mexico.

Customer: replied 9 months ago.
will the furnace turn off once it hits the thermostat temperature, without the limit in place?
Expert:  airheatman replied 9 months ago.

Yes the limit only tells it to shut off if chamber overheats.As long as chamber is not getting too hot, everything is fine.If furnace had been running I would be concerned but since furnace was cold, we pretty well know limit is the problem.

I just can not tell you ever that it is ok to bypass a safety