high limit switch and red tag

[ralphbart]

I have a 20 year old olson/airco high efficency furnace model HSC281AD
an 81000 btu furnace,for temperature rises of 2 to 3 degrees all is fine, for rises of 5 ,6, or more degrees the high limit switch shuts off the gas, cools down, and starts back up I wa told this is no good, you shoud never hit the high limit switch is that so HELP. they say mu furnace is toas is it working right or not?? All help will be greatly appreciated.

[Mustang894me]

could be multipal things .. do you have ac? have you checked filter? is you coil pluged? is blower working? cracked heat exchanger? there are so many thing that could be wrong with you you might want to have a pro come check it out. i doubt the limit switch is bad it is dont its job somthing is wrong get someone there who knows what there doing

[skippedover]

You need to call in an experienced service tech. Many things can cause a unit to hit the high limit but it is true that you should never use the high limit as an operating switch. I'm assuming this is a new phenomonen and not something that's been going on for years. However, having said all of that, a 20-year old unit should be replaced just because of its age. If it were a car it would have 500,000 miles on it!!:eek2: Many improvements have been made in the last 20-years so rather than spend a bunch of money figuring out what's wrong with this one, I'd highly recommend you consider replacement. :payattention:

[surenuff]

do check your filter and coil to be sure they are not plugged. As it is true your unit is very old, it still cold be something very easy to fix and give you ten more years of service. There is a bunch of good reasons to replace it but unless something serious or expensive to fix is wrong with yours, there is no real reaon for not keeping it either. Good luck, but do have someone qualified take a look at it for the sake of your peace of mind.