Goodman furnace model #GPO 125_4 REV 8 Installed 6/2/2002
Going out on high temp. This is a list of things all ready checked
1- Blower running right direction
3-Replaced high temp switch
4-Replaced gas valve
5-Heat exchanger no rings pop lose
6-Heat exchanger looks good from top side,Removed blower
- If you need clarification, ask it in the comment box above.
- Better answers use proper spelling and grammar.
- Provide details, support with references or personal experience.
Tell us some more! Your answer needs to include more details to help people.You can't post answers that contain an email address.Please enter a valid email address.The email address entered is already associated to an account.Login to postPlease use English characters only.
Tip: The max point reward for answering a question is 15.
Jimbo, it sounds like you are aware of the operational sequence to suggest using a voltmeter to check the actual wires going TO the combustion air fan...if there is no voltage from the board, the board is bad. Just make sure one of the high temp limits are not open... one may be in the blower compartment on some and one will be near the top of the vestibule and a roll out switch should be near the burners. They should all be wired in series.
Always check the manual reset safty switches as the first step in troubleshooting.
your limit switch is opening up, that causes constant fan. Check for flashing codes after flame shuts off and fan continues. Check airflow, filters, lack on return air for possible hi temp limit problems.
Sounds like limit switch issue. Furnace heats up, high temp limit switch opens, fan will stay on. GMP model is older and do not have the codes.
May be over fired, have airflow problem, to cause the limit to open.
Next time before shutting off power, try to find the limit, it has two wires that connect to a 1.5 x 2 inch card mount to the furnace fire wall. tap on it and see if the blower stops. If so replace the limit.
Should be able to slow down. Inside bottom door of furnace there are 4 or 5 wires, connected to board and blower motor. White is common. Red is slowest, then orange, blue, black fastest.
1 of these wires should be connected to Air Cond tap, one to furnace tap and 2 to unused taps.
If you are currently running furnace, connect red wire to heat tap. Make sure unit does not get to hot. Should be able to hold hand on Metal duct above furnace without getting to hot. Temp coming out of furnace should be around 35 to 60 degrees higher than temp coming into furnace. Actual heat rise temp is listed inside top of furnace rating tag.
for what ever reason, your shutting down on high temp
4 things to check
1 the filter
2. your fan, is it comming on....... to circulate the heat.
3. your hi temp thermostat is bad and needs to be replaced.... it should be a sqaure with two wires
you can just ohm it out to know sometimes orange but it differs some
4. above your fan are the coils, ar5e they clean and free of restriction
double check your wiring. R terminal on the furnace will provide 24 volts to the t-stat. W terminal in the t-stat will send 24 volts back to the furnace W terminal to turn on the heat. G terminal in the t-stat will send power to the G terminal in the furnace when the t-stat is switched to fan on. Y terminal in the t-stat will send power to the Y terminal in the furnace which in turn will send 24 volts to the A/C outside. The C terminal in the furnace should be connected to the c terminal in the A/C outside as well as to the T-stat. Check the fuse again
Keep in mind all furnaces and circuit boards are not the same. Look on the back of the door to the blower compartment. You should find the list of diagnostic codes. Look up four blinks it should narrow down the problem. Although from the discription you gave it sounds lie the high limit control. When a high limit appears to be acting up it DOES NOT mean that the high limit needs replaced. The high limit just may be doing its job. This means that the furnace is overheating. Check your filters. Are all of your registers open? Is your blower set on the right speed? Is your blower going bad? Is the blower motor capacitor bad? Is your evaporator coil restricted? Just changing a high limit switch does not always solve the original problem!
limit switch is on the heat exchanger black plastic about 1and1/2 in. by 2 in. with 2 wires going to it , it has 2 screws holding it in take it out and check it with an ohm meter and you should not have a reading if it is good
Furnace fails to operate.
• Integrated control module
diagnostic LED is
flashing ONE (1) flash.
• Furnace lockout due
to an excessive
number of ignition
“retries” (3 total)1.
• Failure to establish flame.
Cause may be no gas to
burners, front cover
pressure switch stuck open,
bad igniter or igniter
alignment, improper orifices,
or coated/oxidized or
improperly connected flame
• Loss of flame after establishment.
Cause may be
interrupted gas supply, lazy
burner flames (improper gas
pressure or restriction in flue
and/or combustion air
piping), front cover pressure
switch opening, or improper
induced draft blower
• Locate and correct gas
• Check front cover
operation (hose, wiring,
Correct if necessary.
• Replace or realign
• Check flame sense
signal. Sand sensor if
coated and/or oxidized.
• Check flue piping for
length, elbows, and
• Verify proper induced
draft blower performance.