I have a gas Heil furnace model # NUGS125AK01. It won't light up. The ignitor lights and then goes out. Then it tries over and over and never lights. My buddy began banging randomly inside it and it fired up. I knew it wouldn't last and sure enough today it doesn't work again. I read one of your posts and you said to try the trick where you try to clear out any lint blockages where the rubber hoses connect. Nothing. A red light blinks constantly also but I can't find any diagnostics online for it. Any ideas? TY tim:confused:

Also I have the same furnace and I took the pressure switch off and switched them. Nothing different. So when I switched it back my good furnace worked fine and the bad one remains not working. So here is where I am: Typical operating sequence (some slight variations of timing are likely): 1) Inducer starts and pressure switch engages, 20-35 seconds. 2) First ignition trial begins, ignitor is powered and glows, 17-34 seconds. After this point the furnace does not light up and it keeps trying to ignite but nothing happens. The draft inducer (if that's what it is ((the blower looking device that the pressure switch is connected to)) makes some sqeaky noises sometimes. I also took the rubber hose off it, and tried the paper clip to clear out any blockage and got nothing for results.

A voltmeter would be very helpful in diagnosing the problem. It sounds as if the gas control isn't being powered, or it is but fails to open.

Ty kc any advice on the diagnostics of that model heil furnace? Red light blinking in no order just constant blinking.

Usually a legend of some sort would be present to describe what the LED codes mean. Check the inside of the service access panel(s), or the circuit board enclosure (if the board is enclosed).

No legends any where on this furnace. And none in the manual. This furnace is really pissin me off. Ty kc I got to getsome sleep I ll be back on later.

Also I smell gas after the furnace fails to light its fires. Then the smell goes away after a few seconds. I took the drain, off its hose seemed clogged and when I did I took out this piece of styrofoam and some water came out when I dumped it upside down. I put the styrofoam back in and screwed it back on. Nothing changed . No fire.

If you are smelling gas, the gas control must be working. Check the burners for some type of buildup that may be interfering with ignition.