The older sears furnace here, has a pilot light that lights
But goes out, as soon as the pressure on the pilot button is released. Now two times it did stay lit and then soon went out. If the orifice needs cleaning are there diagrams of where that is or how to do that? Thanks

I'd replace the thermocouple (http://americanhvacparts.com/Merchant2/graphics/00000001/PIL3000.jpg). It is a fairly inexpensive part and easy to swap out. Any hardware store should have them. Probably the big box DIY stores too.

Good Luck,
WallyH

I agree with wally - your problem is the thermocouple. I just replaced mine in about 20 minutes. But my problem was not fixed with this replacement! My pilot light stays lit for a full cycle of heat - or more and then next time I look it is out again and unit is just blowing air. Any help Wally? - BCD

I agree with wally - your problem is the thermocouple. I just replaced mine in about 20 mins. But my problem was not fixed with this replacement! My pilot light stays lit for a full cycle of heat - or more and then next time I look it is out again and unit is just blowing air. Any help Wally? - BCD
I'd make sure that the pilot flame is hitting the thermocouple squarely. If the flame is not keeping the thermocouple hot enough, it could go out. Another thing I would look at is whether there is a draft in your furnace that is blowing the pilot out. It should be a fairly solid flame, with little flickering.

Good luck,
WallyH

I agree with wally - your problem is the thermocouple. I just replaced mine in about 20 mins. But my problem was not fixed with this replacement! My pilot light stays lit for a full cycle of heat - or more and then next time I look it is out again and unit is just blowing air. Any help Wally? - BCD

My problem was fixed so far by not turning the valve all the way on after lighting the pilot! I lit it - let go and turned it all the way on and backed it off just a bit. So far so good. - BCD

It turns out the thermalcoupling was not the problem with this old sears furnace.
I decided to have a hvac tech repair it. The pilot flame would light but not stay
Lit without holding down the button. Took out pilot assembly and cleaned it out.
Big difference in flame size- increased 3 fold. Now flame is enough to "reach" and activate the tc.

It turns out the thermalcoupling was not the problem with this old sears furnace.
I decided to have a hvac tech repair it. The pilot flame would light but not stay
lit without holding down the button. Took out pilot assembly and cleaned it out.
Big difference in flame size- increased 3 fold. Now flame is enough to "reach" and activate the tc.
A clogged pilot assembly will have the same symptoms as a bad thermocouple, but requires a service call. The thermocouple can be replaced by the homeowner, so that's what we hope for.

Glad you found the problem!
WallyH