I have a Coleman Evcon heating and air conditioning unit, model # DGAT070BDD, year 1996, in my double-wide trailer home. It is making an odd beeping noise, something like an alarm. I can't seem to find a manual to help me diagnose the problem. Any thoughts to help me?

There is a alarm for the attic fan in side the furnace right in the middle there is a switch you can shut the beeping off then have it checked out later