Got a Comfortmaker pgf036k100a gas pack. When I cut the heat on, the motor comes on but does not blow heat.

http://www.managemyhome.com//mmh/lis_pdf/OWNM/L0522746.pdf

Your unit has a Honeywell smart valve but to most service people it is called a Honeywell dumb valve. You may try and move the wires around a bit on the gas valve to see if it will come on but other than that unless you have a meter and know how to use it it would be best for you to call a pro for a NO Site visit and repair. There are many parts on this unit that can cause the furnace to fire up and instead of just replacing expensive parts I felt it would be better to have someone check it out and just replace the part that is needed.