How to Troubleshoot a Coleman Furnace's Sequencer

Inspection

• Turn off the electrical power to your Coleman furnace before you begin to inspect it. Loose wires inside the furnace can cause arcing and heat build up. Look for burnt wires inside the furnace. Check the breaker and use a multimeter to test your fuses. If you don’t have a multimeter, replace the fuses to ensure that they’re good. If your furnace still isn’t providing heat, you’ll need to test your sequencers.

Testing

• Make sure the power to your Coleman furnace is turned off. Note wire colors and terminal locations while you disconnect the wires from the sequencer. Use an ohmmeter to test for continuity across the bottom brass terminals. Set the thermostat to heat/auto and test for continuity across the top and middle silver terminals, which are labeled M1/M2, M3/M4. If you do not get continuity, you will need to replace the sequencers.

Replacement

• Removing your old sequencer is as easy as taking off the mounting screw, but make sure you’ve labeled the wires first and made notes about where they connect. Look for the manufacturer’s part number on the relay so you can purchase an exact replacement. If you can’t find the part number, match the voltage, the number of switches and the length of the on/off timings.

Installation

• Mount the switch and reconnect the wires, using the notes you made when you removed your old sequencer. After turning the power back on, you should let the furnace run through a complete heating cycle to ensure everything is running properly.

Coleman

• Coleman sells six different electric furnaces designed for use in mobile homes. Capacities range from 34,000 to 77,000 BTU. The furnaces, and the sequencers used in them, are manufactured by Honeywell. At the time of publication, Coleman sequencers cost between $30 and $47, depending on the model.