My brother's cabin has a heil horizontal mount attic furnace model # NTC 5100 BFE2 that runs on propane. It's about 14 years old. Only 3 of the 4 burners work, but the heat only comes out at 55 degrees. The heat on the exhaust stack outside in 10 degree weather is 98. The main blower clicks on simultaneously, and the induced motor squeals, and on one start up, not at all, with flames coming out against the shield. I'm sure it has multiple issues, but looking for options. The flame was originally orange, but now at least is over 50 percent blue. I'm at a loss as to where all the heat is going.