To bypass the heat pump is the way I would test the furnace. All you have to do is go to the furnace and the two wires that go to the t'stat can be seperated from the t'stat and jumped together. After the fan delay relay has heated up the fan will start and the furnace should begin it sequence to ignite and heat. This bypassing will not check the control circuits of the heat pump; ie, the outside coil temp and relays on the heat pump to control the furnace but will insure the furnace is operating when told by the control circuits.
Mike, RVIA & RVSA Certified Master RV Technician
Amy, Dr. Assistant - Roxie & Mei Ling, four legs each
2000 Gulf Stream Scenic Cruiser 450 hp & 1330# torque
06 Saturn Vue, 06 Chevy Z71 4x4 & 2014 Corvette Z51 M7