Furnace issue need hvac help
 

I've got an Olsen furnace for my garage it loos like a regular old house furnace and it's age is unknown we've been here 18 years so it's that old at least...
I've started to notice the furnace continual runs and blowing cool air...pilot light is on and blower motor running....where do I start to look for an issue....
Any help appreciated.....Chris

no gas, try replacing the thermocouple.

Pilot light is light and running still thermocoupler ????

No probably not . Im not a pro so i dont want to tell you to buy a gas valve that might not work

Either main gas solenoid/valve or an ignition limit switch. Electronic damper by chance?

Electronic dampner I think it's too old to have Electronic stuff in it...

That thing is early 80's. I know you probably don't want to hear it but pony up and buy something safer.

Is the knob on the gas valve set to pilot off or on? seen it set to pilot on a couple no heats through the years lol

your right it’s 84 Ithink isn’t it…wouldn’t. Mind getting rid of it to something I can hang that give me more room…any suggestions

Nope furnace never gets touched…summer or winter it just stays on

Well having a hvac guy coming out to inspect …

You can hang an 80% furnace horizontally. Or a 90%+ furnace. If you do a 90+ you cannot install it where it would be below freezing.

Correct. I heat my garage with an 80 percent natural gas unit i bought new from an auction where they sell new furnaces that are left over from construction projects etc. Remember if you use a house furnace you dont get a 30 degree to 75 temp tise as you generally would with a hanging furnace. but you must keep it at about 60 until you adjust it for the day. insulation is important and where I live a second meter is a commercial rate. My bill for gas and electric for a 24x28 is 100 to 150 depending on how much i weld. Works for me. No moisture in the shop an no rust

Rest switch resolved the issue …..functions like it should..

Glad you got it fixed!

What's a rest switch?

Yep adjusted it and sorry it's the Limit switch it's a long bi metal tube with dis similar metals that control the fan function as well as the gas valve ..theres a guy on YouTube grayfurnace man great explanation of how it works ..if ya wanted to see....

Did the repair tech ck the heat exchanger integrity? A 40 yr old unit is likely cracked or rusted through. Here's a quick test, BUT NOT FOOL PROOF. With the main flame OFF, push in the white button on the fan/limit switch and the fan will start. Watch the pilot flame as the fan starts and if it begins to waver, the heat exchanger may be compromised, allowing carbon monoxide into the space! Pull the switch to stop the fan, now turn the tstat up and watch the main flame as the fan starts. Better yet, use a borescope to ck each bay.

Follow previous advice and replace it. Hang a unit heater with closed combustion that uses outside air for combustion. You will accomplish 2 major improvements, added floor space (which is golden) and removing the OPEN FLAME form the garage for safety. Plus, it may be more efficient.

Yes, I hear everyone out there saying a torch or sparks are an open flame. Would you light a torch or strike an arc if the space was full of flammable fumes? The furnace can't make that decision! Your life, your call! Except when your grandson is helping.

Might want to put a new furnace on your to-do list. Maybe find a scratch and dent unit for sale. The right size modern high efficiency would probably pay for itself in a few years of use .. specially if you can install it yourself.
Modern high efficiency units can exhaust through a 3" PVC pipe and are very quiet.

radiant tube heat is awesome if you replace it.

checks all the boxs for a garage. outside air intake/exhaust/quiet/super efficient/no exposed flame or gas/no humidity returned to your garage.