Gupi100-4 need ignition control module and a control board... not getting 24 to the main valve but can jump start the heater when sequence is started and it will run until thermostat is satisfied but won't restart on its own trying to find parts but there discontinued...thought about running a sequencer but if pilot does not light will just continue to push gas

Try jumping out the rollout TEMPORARILY to see if thats it.The button can be bad.

Hi, if you have replaced the control board and pressure switch, you need to check the sequence of operation. Starting with the inducer motor, must start up to pressurize unit box and be sure the pressure switch is closed. Even though you have replaced this switch, it may not have enough pressure to close it due to condensation in hose, a leak and so on. Jump across this switch to see if the pilot will light next. If this unit has a flame roll out switch located by the corner burner, make sure it is not tripped. Sequence of operation is, first your inducer motor will start and vent old gases and build pressure. Pressure switch will make and send signal to ignitor board to start pilot. If you have a HSI pilot, (Hot surface ignition ) it will glow. Next it gets the flame sensor hot enough to send a signal that the pilot is proved back to the board to fire the main gas smart valve with 24 volts. Go through this check as I have layed out. The flame sensor is right along side of the pilot tube and if the metal tip gets dirty, it will not fire. You can clean it with sanding cloth or fine steel wool to clean. If you go through all of these steps and it will not fire after you have made sure you have 24 volts ac at all controls in the sequence I have said, check the main gas valve across terminal C and MV for 24volts. If you have 24volts and it won't open the valve, it is faulty. Check this out for me and let me know. If no 24 volts, you have missed a safety in the sequence.
Sincerely,
Shastalaker7
A/C, Heating& Refrigeration Contractor

Hi, It says this problem is still not solved, but its been 4 months ago? Anyway, when this happens, the inducer motor will start on a call for heat, close the pressure switch and then the glow plug will turn orange or a ignitor module will turn on for a few seconds and then the gas valve should be energized by the control module to open and start the heater. So, on your heater you will have what is called a flame sensor that lays along side of pilot tubing and is porcelin with a metal tip and a wire coming out the back that plugs into the module. It senses heat by pilot flame or direct heat and will send a signal back to module to open main gas valve. If you have no pilot at all, you need to check to see if you have gas to the unit first. Get a good sized adjustable wrench and loosen the gas flex coming to the valve to see if you smell and hear natural gas. Bleed it off to get any air it may have. Tighten back down and make sure you have no leaks. You need to get a cheap digital meter. They are very inexpensive. Go to Sears tools and get one for around $19.99 a craftsman.Set the dial to ac voltage the lowest setting above 24 volts what ever the scale reads, such as 200 vac.Now start you furnace, but be for you do take the red and black leads of the meter and put the red lead on one of the connections that reads MV and other to C. Now start the heater and let it go through the sequence of operation. When the ignitor starts to click to light the pilot, the meter should read 24 volts at the valve. If the vale has more then 2- wires, see if it is marked PV and put your red lead to this the pilot valve. As it is clicking there should be 24 volts ac there to open pilot valve. If not, the control module is faulty, only if there is 24 volts to it and you had gas at the flex line. If you have no voltage to this gas valve when the control module or board is clicking, this module will be faulty as it is not putting out 24 volts to the gas valve if you have gas to it. This is a simple check. If you can see a pilot light back there and the gas valve will not open, you will need to check this flame sensor. Carefully remove it. Take a light piece of sanding cloth and clean up the metal tip on it. Now install it and make sure the tip is in the pilot flame. Start it back up and it should fire the MGV to open right away. This should have taken care of your problem. let me know the out come.
Sincerely,
Shastalaker7
A/C, & Heating Contractor

Check for 24 volts across the gas valve when Ignitor is glowing. If no, bad board. If yes, bad gas valve or blockage.
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).

Jump the R and W terminal on the control board. If it tries to start, bad thermostat or thermostat wire. If not, bad board or something else read on for 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).

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).

If you are referring to the thermostat, try jumping the R and W wires together. If it starts, replace the thermostat. If not, go to the furnace and jump the R and W terminals on the circuit board. You may need to tape the door safety switch closed. If it starts, you have a bad thermostat wire. If not, check out the sequence of operation as below.

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).

Does the ignitor glow? If not, make sure it is getting 120vac to it after the inducer motor comes on...and you can not take the wires off of the ignitor to check them that way, you will get a false positive reading. It has to be hooked up and you can check at the IND and Neut on the board. If it is working, make sure you are getting 24vac to the gas valve. If you are not, you need to check all the limit switches on that purple wire between the board and the valve. If you are getting 24v at the board at the correct time and not at the valve, one of the limits is open. NOTE, you can read 14 volts or close to the valve from the time you have a call for heat, that is normal, but the voltage should jump to 24 about 5-10 seconds after the ignitor starts to glow. After 3-4 seconds if no flame is present, the flame sensor circuit will start the sequence over 3 times then lock out (code1) for one hour and retry.

The whole assembly must be replaced.

The sequence of operation is -

Combustion fan purges the heat exchanger. A pressure switch verifies combustion air fan is running. Usually a 30-45 second purge before the hot surface ignitor glows, or the spark ignition starts.

Gas valve opens after 10-15 seconds and main burners light. Control board monitors for flame and shuts gas valve after 2-3 seconds if main burner does not light.

If burner does not light, some boards repeat this for 3 tries, then locks out and is reset by cycling power.

Air blower comes on after another 30-45 seconds after main burner ignition.

Times may vary based on the specific controller board. A flow chart and timing sequence should be located somewhere on the unit, usually in the fan compartment.

You will find an error code chart on the wiring diagram pasted to the reverse side of one of the panels. It will help you to know where to start looking for the issue. I am also sending you the sequence of operation to give you a few more pointers, read on.

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).