I have a 1977 Luxaire unit heater in my garage (UH100LF) that has normally worked, but this year having trouble keeping pilot light lit. It has a combination valve (off, pilot, on). You rotate knob to pilot and press down for 30 secs to light pilot. The knob needs to spring up to rotate to the on position, but when it springs up enough to allow it to rotate, the pilot turns off. Any ideas?

Gas control unit V800A1005 Regulator 5306A and Operator V804 ---- label off valve

Replace the thermocouple. That is the usual problem for that design system. It is located next to the pilot lite and attaches to the gas valve. It is a much smaller diameter than the pilot gas tube which is aluminum.

Thanks. Just took it out and cleaned it up with sandpaper and it is working now. :) Appriciate the response!

Glad you got it going but I never heard of sanding a thermocouple.

How do you replace the thermocoupling. The part next to the pilot light is hard to get to. I need help.

I have question not an answer that is related to the question.

How do you replace the thermocoupling. The part next to the pilot light is hard to get to. I need help.

You will have to disassemble whatever is necessary to get to it. Once it is out then you can replace the thermocouple. A step by step is not going to help since I cannot see what you have exactly.