Old Dayton Furnace

I have an old Dayton furnace, Model 3E437A, Mfr# GUGK075DG02. Seems to be from some time around 1987. Attached is a picture with the info. I’ve had two heating guys come in, one of which is very reputable, and both said that the furnace is in great shape for its age and one of them said it looked barely used. It seems to be working fine for the most part, but the reputable guy said there were a couple of things to watch out for. The exhaust blower motor bearing is starting to sqeal and has been getting worse over the past two months. And a limiter switch may be starting to act up. Lately it will stop firing (but continues to blow) and within several seconds will begin firing again. Doesn’t happen every time though. Seems to be mostly on long cycles like when I kick the thermostat up a couple of degrees. My issue is that the parent company, Granger, no longer has parts for this unit. So what to do now? Is there no other option besides replacing the unit which will cost me around $3,000? Is it possible to find parts that can be substituted? The reputable guy that I had in said he can replace the exhaust blower for $500. This seems like too much for such an old unit. I would like to be able to repace it myself because it doesn’t look too difficult to get out, I just can’t get the part. I am very mechanically inclined and am more than able to do it if I had a part that I knew would fit.

Forgot to mention it has an AFUE of 90%. I know it loses some over the years but stepping up to a 92% (which is the price point I can scrape by with) doesn’t seem like it would save me a whole lot.

I would say 1987. The ANSI date is 1986.

Last manufactured in 1990.

The serial number of L874737886 seems to agree with you.

Parts may be available here: http://heatcoolparts.com/contactpage.html

This may be a nachi first. No one told a DIY’er to contact a professional. Could the motor be rebuilt perhaps?

dayton furnace 3e437a was made by inner city products for dayton the exhaust blower can be gotten from fasco part 7062 4578 hq1011350fa most other parts can be gotten from american hvac parts on the computer