Replaced control interface panel and transformer, igniter glows and gas valve clicks but no ignition. have run volt tester and all is up to spec.

Have you checked the wires from the board to the gas valve? You should get 24 volts after igniter glows.

Hello, sometimes even though the igniter is glowing it can be weak and not able to ignite the gas. Also, since the gas valve is clicking that means that it is receiving 24 volts but it is also possible that gas valve is sticking and not allowing gas to flow to tne buners everytime.

There are many things to check. The single most important test is for 24V at the gas valve after the ignitor is supposed tp be on. 19 V or less and there is either a bad ground or the ingition control board has failed. (Wire ground problems are a high probablilty)

Here is what the book says:

PROBLEM #1 - HOT SURFACE IGNITOR DOES NOT GLOW RED

(Remember to wait for purge time, 17/34 seconds, on models so equipped).

Possible causes

A. No main power

B. Faulty transformer

C. Faulty thermostat

D. Faulty limit switch

E. Faulty blower interlock switch

F. Faulty hot surface ignitor

G. Faulty ignition control

Solution

Step #1

Perform normal system checks of main power, transformer, thermostat, limit

switch, blower interlock switch, and replace faulty component.

Step #2

With power on and thermostat set at its highest position, check voltage

between "TH" and "TR" on HS780 ignition control. If 24 volts is not present

check output at transformer. If no, replace transformer. If transformer

checks out OK look at other controls in the 24 volt circuit I.E.: thermostat,

limit switch, blower interlock switch. Check for 120 volts between "neut"

(L2) and "120" (L1). Check for 120 volts at the ignitor across "IGN" and

"IGN" terminals on the HS780 ignition module. If 120 volts is present,
replace ignitor. If no, replace the 780 series module

PROBLEM #2 - IGNITOR GLOWS RED BUT MAIN BURNER

WOULDN'T LIGHT

Possible causes

A. Improper ignitor alignment

B. Faulty ignition control

C. Faulty gas valve

D. High inlet gas pressure

E. Polarity reversed

F. No earth ground

Solution

Step #1

Check for availability of gas at gas valve. Make sure the manual valve

upstream of the gas valve and the gas valve are in the full on position. Also

make sure gas is being supplied to the system at the proper pressure, too

high will lock-up the valve.

Step #2

Check proper polarity of "NEUT" and "120" on the ignition control by reversing

the wires, if reversed gas valve will not open. If this does not solve the

problem, replace wires as they were.

Step #3

Check for proper ignitor position.

Step #4

Check for a good earth ground by using a meter connected between L1

and furnace chassis. Should read 120 volts, if no, check and/or repair ignition
ground wire or ignition control mounting screws.
CAUTION POLARITY MUST BE OBSERVED

Step #5

Check for 24 volts at the gas valve terminals; "1" and "2" on a 7200 series,

"M" and "C" on a 7100 series, "TH" and "TR" on a 7000 series. If yes,

check wire integrity or change the gas valve. If no, change the 780 series
ignition module.

That is pretty much all of the troubleshooting required.

Thanks for choosing FixYa,
Kelly

The oven control supplies voltage to the oven igniter/gas valve circuit. When the oven control is set to Bake, voltage is supplied to the oven igniter which should glow bright red to almost white hot. Once the igniter comes on and begins to glow it must pull enough current to cause the gas valve to open so the burner can ignite from the igniter. I added an image below with the theory of operation. Click this link:--http://media.fotki.com/1_p,swbbsqrsgstsqkkxgtqsskgwtqkq,vi/wrgtsbrktxwdfwfbgdg/1/1303472/5961857/image5576034710104836299img-or.png

----Open the broiler drawer and then set the oven control to bake and watch to see if the glow bar igniter glows or not. If it does not glow, the failure could be a broken Igniter, failed oven control board or gas valve. If the igniter is glowing red, then it can be possible that gas valve is faulty. To see how igniter looks. See the fig below:--

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To order this part click the link below:--

http://www.repairclinic.com/PartDetail/Hot-Surface-Glow-Bar-Igniter/1990?modelNumber=911.30469894

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Also to confirm, check to see if the igniter is getting 120 volts when it's turned on. If it gets 120 volts, then your safety gas valve is bad because it's not letting the neutral go through. Otherwise, if it's NOT getting 120 volts, your control board shorted out and you need a new control board.
But as you mentioned that control board is replaced. So igniter should get 120 volts. If valve is faulty. But if igniter is not glowing then its faulty igniter confirmed.

To see how gas valve looks, please click the link below:---

http://www.repairclinic.com/PartDetail/Gas-Safety-Valve-Assembly/251898

In most of the cases the igniter is faulty, because gas valve getting faulty is very rare. But still getting the voltages checked, will confirm. These will help. Thanks. Helpmech.

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).

Check gas pressure, inspect manifold & make sure there is not a blockage.Make sure gas is present and main gas shut off valve to furnace is on also check the knob on the 24 volt gas valve and see if it is in the on position , check the MV terminal on the gas valve to 24 volt common with a volt tester to see if you have 24 volts present, if you do have 24 volts at gas valve, replace valve. if you do not have 24 volts at gas valve check high limit control & roll out limits for a open circuit, Good luck.

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).

bad board,i have had several board failures on goodman

Goodman gmp075-3 gas furnace and the flame cycles for 4 sec

OK, if the furnace is not lighting for even a few seconds, you have either a bad gas valve, bad wire, bad control module or no gas. The pressure switch is not the issue. Check all wires to the gas valve and look for 24 volts across them when the ignitor glows and you hear the click. Then test for 24 volts to ground. It could be a bad ground wire.