SOURCE: red light blinking continuosly meanig gas valve
You will need to check for 24 volts AC to the gas valve after the igniter starts sparking or glowing. If you have it but it does not open, bad gas valve and you will need to replace it. If you are not getting 24 volts after it starts glowing or sparking, you have a bad board.
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).
SOURCE: MHU 75 Model Mr. Heater
The roll out switch is a small disc shaped part about the size of a nickle. There may be more than one. anyway there is a button shaped like a small peg in the center if it, push it in and it should stay in. You may need to re examine the limit switch, because this is what it sounds like. they are rated for a set temperature, so your application may need a higher temp. A simple way to check parts like these is to by-pass them by taking the wires off the part and connecting them together. If this solves the problem, that it. My only concern is that this is a new installation, and maybe its not venting adequately or its burning up all the usable air in the room. That's why most of these parts are on the equipment.
SOURCE: 1993 goodman status light 4 times blinking
I have a goodman GMP075-3 that won't turn on. I think it is the pressure switch since I do not have a vent blockage. What is a venter and where can I find it??
SOURCE: furnace short cycles
turn electric off to heater, there should be a light switch on the side of the heater that cuts electric off to the heater. find the flame sensor, unplug wire to it and remove from heater being careful not to touch it with your hands or fingers, because of the oils in our skin. you can touch the part that the wire plugs to. when you get it out take fine emery cloth and clean the probe side or the sensor side real good and reinstall it. plug the wire back in and try heater. it should work fine. the sensors sole purpose is to detect flame and when it gets dirty with carbon it cant. so the sensor false reads and tells the heater its shooting raw gas into the heater and the heater shuts down, or short cycles, its there incase the ignighter fails. hope this helps you. it cost me 105.00 for this info. write it down in your owners manual so you dont forget it. the symptoms and the cure.
SOURCE: my furnace tries three times then red light blinks once
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).
Your furnace has a diagnostic chart on the reverse of the lower panel incorporated in the wiring diagram. One blink tells you that it is a failure but wont tell you where to start looking.
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