Suburban NT-30K Furnace Won’t Light

[Dano73]

The furnace in my ‘90 excella doesnt want to start anymore. I’ve owned it for about 10 years and when I bought it the owner told me to just take some sandpaper to the electrodes and it would fire right up, but not anymore.
I’m really kinda lost as far as troubleshooting this goes, if anyone could direct me to a site that could walk me through it, I would appreciate it. I think my next move is to take it out of the housing, and blow it out with compressed air, Im sure it’s never been cleaned before, way overdue.

[kenfconnor]

I am not sure what units (year) are impacted but I suspect that furnace may be included in the old safety "recall". I had a similar vintage and had a new furnace installed. The do age and I would not sleep knowing I had a 30 year old furnace. A new one is not that expensive and meets current safety standards.

[Al and Missy]

When mine failed to light the problem was the electrode had developed a leakage resistance short that kept the voltage from building up to make a spark. Check to see if you have a spark. If not, disconnect the electrode and see if you can get a spark to the cabinet of the furnace. If you do get spark there you need a new electrode.

Al

[Dano73]

Thanks Al. I do get spark at the cabinet, and you are correct, I may need a new electrode. I think I am going to remove the heater, and blow it out with compressed air, as it says in the manual, part of routine maintenance. Lol. Make sure all the dust is cleaned up, and then if no ignition, I will replace the electrode, which is obsolete, but I found a guy that has one.

Chris

[Dano73]

Took the furnace apart and cleaned the combustion chamber, and it’s working again. I believe the rust buildup on the burner probably had everything to do with the ignition problem, much like chimney rust will snuff out your fridge flame. It obviously doesn’t get used that much, so It appeared to be in remarkably good shape. Nice to have as a backup when camping in the cold, heats up fast, and shoots some hot air to the tanks if needed, as we try to make sure we’re plugged in if it’s that cold.

[kenfconnor]

Glad to hear you were able to resolve. Just for closure since I brought it up on this thread the recall was for much older units. 1966-1977. Details below:

Suburban initiated a recall for all furnaces made from 1966 through 1977:
Campaign : 77E-012 initiated summer of 77
Campaign : 81E-015 initiated winter 81-82
The furnaces were models NT-17, NT-20, NT-22 and NT-30 manufactured between 1966 & 1970 The serial numbers were 0064881 and lower.**Also furnaces made between 1970 & 1977 except those with an "M" suffix, The serial numbers are: 0064881 through 0715865.**The recall specifies:" if the model and serial number of your furnace falls within those noted, have it inspected unless you are VERY SURE the Suburban recall has already been completed on your unit.**The furnaces in question have a rubber-like crossover tube that could crack.**Extremely dangerous carbon monoxide would then be expelled into the interior.”