At Fixya.com, our trusted experts are meticulously vetted and possess extensive experience in their respective fields. Backed by a community of knowledgeable professionals, our platform ensures that the solutions provided are thoroughly researched and validated.
Goodman GDT070-3 Replaced Circuit board, limit & pressure switch, flame sensor. Worked all winter. Now Igniter lights flame draft motor starts good flame then there is humming noise and it shuts off.
Bad inducer motor most likely. Check the leads and plug. If it just homms, it is stuck. Check to see if the drain hoses are free of moisture. Can you get to the shaft to spin it to see if it is free?
Clean the sensor with a piece of fine sand paper. It gets a coating on it after a few years of service. I had my cleaned for $160, it took five minutes.
- 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.
Any light flashin on the control board? If not then look for a small fuse blown on the board. See lights a flashing count them flashes
A sampling of various failure codes on a furnace:
Read one LED flash that stays on continuously to mean your furnace has no signal coming from the thermostat and will not operate. Turn the power off and check the thermostat for improper settings or connections.
Interpret one LED flash that blinks on and off to mean your furnace has locked out because it could not ignite after three tries, and must be reset. Interrupt power to your furnace for 20 seconds or lower the thermostat so your furnace does not try to heat, then reset the thermostat to the previous setting. After one hour of lockout, your furnace will automatically reset itself and try to operate as usual.
Decipher two LED flashes to mean the draft blower is not working, or your furnace has a short in the pressure switch circuit. Turn off the furnace power and repair a short or replace the pressure switch.
Read three LED flashes to mean your furnace has an open pressure switch circuit or it has an induced draft blower operating. Check the pressure switch hose of your furnace for blocks or an improper connection. Also, look for blockages in the flue, and tighten any loose wiring.
Translate four LED flashes to mean your furnace has a primary limit circuit open, possibly from loose wiring or blocked filters. Check and clean filters, tighten wiring and check the flue for blockages.
Interpret five LED flashes to mean your furnace senses a flame without a call for heat. This could be from a gas valve closing slowly or a burner flame lingering.
Read seven LED flashes as a warning of a low flame sense microamp signal. This could happen with a coated flame sensor or a lazy flame from poor gas pressure. Turn off the power and adjust the gas pressure according to the information on the rating plate.
See eight LED flashes as meaning an igniter circuit problem due to a bad igniter or an igniter connected improperly. Replace the bad igniter or check the ground wiring, making necessary corrections.
Decipher nine LED flashes to mean the high-stage pressure switch circuit will not close during a high-stage-induced draft blower operation. Your furnace may have a pinched or blocked pressure switch hose, a blocked flue or loose wiring.
Read continuous flashing on the LED to mean your furnace has a reversed polarity of 115 volts. Turn off the power and correct the wiring polarity after reviewing the wiring diagram.
Read one LED flash that stays on continuously to mean your furnace has no signal coming from the thermostat and will not operate. Turn the power off and check the thermostat for improper settings or connections.
Interpret one LED flash that blinks on and off to mean your furnace has locked out because it could not ignite after three tries, and must be reset. Interrupt power to your furnace for 20 seconds or lower the thermostat so your furnace does not try to heat, then reset the thermostat to the previous setting. After one hour of lockout, your furnace will automatically reset itself and try to operate as usual.
Decipher two LED flashes to mean the draft blower is not working, or your furnace has a short in the pressure switch circuit. Turn off the furnace power and repair a short or replace the pressure switch.
Read three LED flashes to mean your furnace has an open pressure switch circuit or it has an induced draft blower operating. Check the pressure switch hose of your furnace for blocks or an improper connection. Also, look for blockages in the flue, and tighten any loose wiring.
Translate four LED flashes to mean your furnace has a primary limit circuit open, possibly from loose wiring or blocked filters. Check and clean filters, tighten wiring and check the flue for blockages.
Interpret five LED flashes to mean your furnace senses a flame without a call for heat. This could be from a gas valve closing slowly or a burner flame lingering.
Read seven LED flashes as a warning of a low flame sense microamp signal. This could happen with a coated flame sensor or a lazy flame from poor gas pressure. Turn off the power and adjust the gas pressure according to the information on the rating plate.
See eight LED flashes as meaning an igniter circuit problem due to a bad igniter or an igniter connected improperly. Replace the bad igniter or check the ground wiring, making necessary corrections.
Decipher nine LED flashes to mean the high-stage pressure switch circuit will not close during a high-stage-induced draft blower operation. Your furnace may have a pinched or blocked pressure switch hose, a blocked flue or loose wiring.
Read continuous flashing on the LED to mean your furnace has a reversed polarity of 115 volts. Turn off the power and correct the wiring polarity after reviewing the wiring diagram.
Replacing the board, flame sensor, and pressure switch, and cleaning out the induction motor was definitely a good start. Other things to check would be a blocked or restricted flue pipe, I have ran into a few bird nest before!, and you also want to check or replace the hose that runs from the inducer to the pressure switch if you haven't already. To be honest, most of the time I clear out the nipple on the inducer where the hose goes with a small piece of wire and it works. The last thing I would suggest is making sure the new pressure switch is rated for what you need. Alot of the revisions on furnaces actually call for less than the original pressure just for this problem. Hope this helps and good luck!
That thang might be sensing a lazy flame. In other words the flames took too long in the board's opinion to quit sensing the flame. Yall probably need to do pressure tap on the gas valve. Here is a realistic look at goodman fault codes and what to check fer and I am assuming you are not a tech and don't know this already and am hoping it helps:
Read one LED flash that stays on continuously to mean your furnace has no signal coming from the thermostat and will not operate. Turn the power off and check the thermostat for improper settings or connections.
Interpret one LED flash that blinks on and off to mean your furnace has locked out because it could not ignite after three tries, and must be reset. Interrupt power to your furnace for 20 seconds or lower the thermostat so your furnace does not try to heat, then reset the thermostat to the previous setting. After one hour of lockout, your furnace will automatically reset itself and try to operate as usual.
Decipher two LED flashes to mean the draft blower is not working, or your furnace has a short in the pressure switch circuit. Turn off the furnace power and repair a short or replace the pressure switch.
Read three LED flashes to mean your furnace has an open pressure switch circuit or it has an induced draft blower operating. Check the pressure switch hose of your furnace for blocks or an improper connection. Also, look for blockages in the flue, and tighten any loose wiring.
Translate four LED flashes to mean your furnace has a primary limit circuit open, possibly from loose wiring or blocked filters. Check and clean filters, tighten wiring and check the flue for blockages.
Interpret five LED flashes to mean your furnace senses a flame without a call for heat. This could be from a gas valve closing slowly or a burner flame lingering.
Read seven LED flashes as a warning of a low flame sense microamp signal. This could happen with a coated flame sensor or a lazy flame from poor gas pressure. Turn off the power and adjust the gas pressure according to the information on the rating plate.
See eight LED flashes as meaning an igniter circuit problem due to a bad igniter or an igniter connected improperly. Replace the bad igniter or check the ground wiring, making necessary corrections.
Decipher nine LED flashes to mean the high-stage pressure switch circuit will not close during a high-stage-induced draft blower operation. Your furnace may have a pinched or blocked pressure switch hose, a blocked flue or loose wiring.
Read continuous flashing on the LED to mean your furnace has a reversed polarity of 115 volts. Turn off the power and correct the wiring polarity after reviewing the wiring diagram.
Now here is how it should all go down:
Bottom dollar: it all goes back to type of gas, the initial setup, the pressure tap. and how it is wired up to begin with. This will give you an idea where to start I hope.
It sounds like you got a tough one there.When you say the blower starts up and then the igniter comes on are you refering to induced draft motor or main blower. The proper sequence is for the thermostat to call for heat at which point the induced draft motor should come on and run for 30-45 seconds,then the igniter should heat up for a few seconds then gas valve should open and main burner should light. After limit switch reaches set point for fan on ,blower should come on till after heat has reached thermostat setting then burner should go out, and blower run until fan off setting is reached on limit switch. If your furnace is not following this sequence and then not always doing the same thing in the same order,I would recommend that you change out board again. I have had several problems similar to this with Goodman units and all but one time installing new board solved it. That time I did everything I knew to do and talked to factory service techs repeatedly and finally installed new furnace. As far as your question about insulation,. As long as it is fire proof I can't see where it would hurt anything. Sorry I'm not more help. Good luck and thanks.
Problem: Your furnace will not ignite the gas to produce heat
for your home. When a furnace has a bad igniter what I see most of the time is
the following sequence of operation:
1. Thermostat calls for
heat. 2. Draft inducer motor starts. 3. Pressure switch attached by a
small plastic or rubber tube senses the negative pressure produced by the draft
inducer and closes. 4. Draft inducer runs for 30 seconds to a minute before
you hear a gas hissing sound. The ignitor did not glow, the flame sensor (a
small metal probe about 1/8" in diameter, with a white porcelain base) does not
sense the flame, so after 8 to 10 seconds the hissing sounds stops with no
ignition of gas to heat your home. Your furnace shuts down and goes into a lock
out condition until you turn your power switch back off and on again. Then the
sequence starts all over again with no ignition of the gas. Solution: You
probably need to purchase and install a new igniter. I would suggest that you
inspect your igniter closely for cracks. Make sure you do not touch the igniter
with your bare hands. If you do not visually see a crack, then you could have a
furnace control board problem or a limit, roll-out switch problem. The furnace's
control board might not be supplying the voltage to the ignitor. If your
furnace lights and the gas stays on for 8 to 10 seconds, then shuts right back
off, then you need to clean your flame sensor with light sand paper or steel
wool. You might need a new flame sensor, but most of the time they can be
cleaned an will work well after cleaning.
One blink means it didn't light after a number of attempts. You replaced the circuit board and gas valve. Read on for some suggestions.
On a call for heat, the 24 volt thermostat sends a signal to the control module. The control module will indicate a call for heat with a light on the control either blinking or remain solid depending upon model. The inducer (exhaust) blower will purge all gasses from the furnace and pressurize a pressure switch. Once the pressure switch tells the module to continue, the electronic ignition will energize and send 120 volts to the igniter. The igniter will glow and you will be able to see it if viewed thru the small inspection port. Once the igniter gets hot enough, it sends a signal to the module opening up the gas valve (24 volts). Either a pilot will come on or the burner tube will ignite then spread the flame to all burners. Lastly a safety sensor will be looking for a certain temperature within a few seconds and the furnace will continue to operate and the room air blower will turn on in a minute or two.
What could go wrong? The unit will not run if there is no signal from the thermostat (bad thermostat or broken wire), the control module does not sense a signal from the thermostat (bad control), the inducer does not energize (bad motor), the pressure switch does not close (blocked vent piping, bad switch, plugged condensate hose), the igniter does not energize (bad control, bad igniter), the gas valve does not open or there is no gas (bad gas valve, broken wire, no gas), the pilot does not light (dirty pilot), the burner does not light (bad burner, plugged orifice, not enough combustion air), the flame does not spread to each burner (bad flame spreader, dirty flame spreader, more bad burners), the flame safety sensor does not detect flame (dirty or bad flame spreader, bad flame sensor, broken wire, bad control), or the room air blower does not energize (bad fan motor, bad control).
1
1 FLASH
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
sensor.
• 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
performance.
• Locate and correct gas
interruption.
• Check front cover
pressure switch
operation (hose, wiring,
contact operation).
Correct if necessary.
• Replace or realign
igniter.
• Check flame sense
signal. Sand sensor if
coated and/or oxidized.
• Check flue piping for
blockage, proper
length, elbows, and
termination.
• Verify proper induced
draft blower performance.
If your igniter comes on but no ignition, that eliminates the possibility of a bad or clogged pressure switch, high limit or flame rollout switch. Sounds to me like you have a control board, or a gas valve going bad. Could even be some loose, corroded, or faulty wiring. Before the igniter comes on the furnace does a self diagnostics to ensure everything is working, or the furnace will not make it to the igniter sequence. Inducer motor, pressure switch/s, limit controls are closed…then comes on the ignitier, gas valve opens, pilot runners and burners ignite, flame sensor detects the flame, blower comes on and all operations are working.
×