Trouble - Goodman GMP100-3 Rev B
This is my first post (newbie). Greetings.
I'm having trouble with my furnace. Goodman GMP100-3 (Rev. B).
This past weekend, my wife and I noticed the furnace was running but there was no heat. The blower was functioning properly, but no flames from the 4 flame ports (sorry, I not sure of the proper term). I followed the instructions on the unit to restart the direct ignition system. I shut off the switch on the side of the furnace (electrical). I shut off the gas valve and the gas control switch (moved from "ON" position to "OFF", and I turned the thermostat to "OFF". I waited the recommended 5 minutes and turned things back in the order listed in the instructions. I tried this 3 different times. Nothing. Blower still worked, but no flame. I called for a service call. In the meantime, I removed the fuse from the control board, inspected it, and returned it. It was fine. The final time I tried the automatic ignition procedure, I waited 20 minutes, instead of the recommended 5. This time it worked. The igniter glowed brightly and the 4 gas ports fired up. I tried it again. Same result. It's been working ever since. The fault code LED glows a constant red. Per the fault code chart, this is the sign for normal conditons, so the board seems to be ok. I decided not to cancel the service call just to have a trained professional look at it. He said the limiter had probably tripped. He told me these will do this only so many times and then stop resetting themselves (safety measure). He also mentioned the furnace was not drafting properly. He also told me he doesn't usually recommend replacing anything but the igniter and maybe the flame probe on the Goodman's. He said they are junk. He mentioned the furnace probably wouldn't make it through the winter. He did seem fair and honest. He came recommended from a neighbor. I'm not sure of the age of the unit (it has "1993" stamped on the product info. tag inside the unit). I'm trying to decide whether to just replace it with a Rheem (he recommended this unit) or keep my fingers crossed with this one. Any suggestions as to other causes of the failure to ignite? The flame probe seems to be in good shape (no oxidation) and the igniter glows a nice continuous orange (no cracks).
Thanks in advance for any help.