pilot wont stay lit

[ladysliberty]

I have a Coleman Presidential II model# 7680C856, every morning I have to light the pilot light, most times it will stay lit all day..sometimes not, but have to relight every morning. Could it be the heat exchanger?

[TECH X]

It sounds like a venting issue.  Has anything changed in the house recently?  New windows, exhaust fans ect...

After a cold night and prolonged operation, it's possible either a venting issue or a cracked heat exchanger is causing the pilot outage.
The pilot may be wired in series with a safety.  If flue products are spilling back into the furnace then the pilot would drop out.

For your safety I would have the furnace inspected.

If your furnace has a standing pilot, I would be looking to replace the furnace.  Age vs Repair.  Get a high efficiency variable speed furnace.  You would most likely qualify for rebates, and the energy savings would pay for the new furnace within 5 years.  It's a great investment.

[ProTemp]

Tech X is right! Pilot light outage can be several things. Call an expert to do a home visite.

[peglegsmith]

Seems to me that Coleman Presidential unit is probally a downflow furnace in a mobile home. These things are famous for having cracked heat exchangers. The old Intertherm counterflows also.
Here is an easy procedure I was taught many years ago for checking the heat exchangers on an old Coleman or Intertherm.
Start the heat cycle. Ask you customer for thier salt shaker. Pour some salt into your hand. When the fan starts watch the flame and throw the salt into the fan. If the flame turns yellow it means the salt is burning and the heat exchanger is defective. Strongly suggest replacing the furnace over trying to find a replacement heat exchanger. It makes better financial sense.
There are some commercially availble products that do exactly the same test in the same way, but, using the customer's salt eliminates a bunch of suspicion.