I need the operating instructions and repair or service manual for a Sears wall heater model number 867.734731 which was working well until it stopped and I cannot relight the pilot. This is a 21000 BTU max unit.

You will have to replace the thermopile. See: http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&ved=0CHkQ FjAC&url=http%3A%2F%2Fscholar.lib.vt.edu%2Ftheses% 2Favailable%2Fetd-8497-205315%2Funrestricted%2Fchap2.pdf&ei=q_irTsa1Nc6ht we2qPzXDg&usg=AFQjCNE-4KaY1IOEvPBZ8MpNmOAJHBbWiw

It supplies electricity to keep pilot light on and to operate the gas valve. It has a rod that is heated by the pilot light on the 1/2 inch of the tip. Make sure to adjust it when you replace it or it will not work, or the life of it will be short. If electricity is supplied to heater from an external source then you will replace the thermocouple, instead, which looks like a thermopile and is adjusted the same way. DrTom4444

Need part for model#8676645, MFGRS.#75643-J5

http://data:image/jpeg;base64,/9j/4A...QBQBQBQH//2Q==Sears no longer lists this furnace, but the parts for it can be found at C.C. son or Baker Supply Company in Jacksonville, FL. Ask for a thermopile or search on Google for "thermopile" and you will find them. They range in price from $28.18 to $53.15, depending on the one you need. Take yours out and match it to the pictures. The thermopile has two wires and a thermocouple screws in a socket. You need the thermopile.

Here is a picture: http://cloudfront.zorotools.com/prod...2Z418_AS01.JPG