Boards Switches Sensors

Harman coal and woodstove replacement control/circuit boards, switches, and safety sensors. We offer control boards, ESP thermistor probes, thermostat sensing room air probes, vacuum/pressure switches, snap switches, hopper muffler, and furnace fan limit switch.

Showing 1–16 of 17 results

The Harman Mark I coal stove will use the 4 output platinum control/circuit board part 3-20-05374, 1-00-05886. The Harman Super Mag Stoker will use control/circuit board 1-00-06142. The control board works in tandem with the other components in your Harman stove, essentially controlling all aspects of operation. We highly recommend a surge protector of at least 1000 joules to prevent any surges or strikes from harming the control board. When it comes time to replace your Harman control board, follow along with our video below.

Harman offers two different ESP thermistor exhaust probes, a red wire probe and a black wire probe. When replacing an ESP probe you want to make sure you are replacing it with the same wire color ESP. We carry ESP probe replacements for the 44 Magnum Stoker, DVC 500, and Mark I models. Be sure to read model notes and serial number notations when ordering. The black wire ESP thermistor probe is part number 1-00-00744, 3-20-11744, and the red wire ESP thermistor probe is part number 3-20-00844. The ESP probe is monitoring temperature in the exhaust and providing signal to the control board during operation. See our video below on cleaning and replacing the Harman ESP thermistor probe.

The Harman room-air temp thermostat probe, part 3-20-00906, is used on the DVC 500, Mark I, and Super Mag Stoker models. This sensing probe measures approx. 5' in length and connects into a port on the rear/back side of your Harman. This probe works like a thermostat detecting room air temperature and providing signal to the control board when operating your unit on 'room temp' mode. If your unit is not working correctly or holding temperature when operating in room temp mode, we recommend you inspect this probe.

Harman Mark I coal stove models will use vacuum/pressure differential switch 3-20-6866. More recent Mark I models will have a fuel hopper muffler and fitting part 1-00-18186618, inside of the fuel loading hopper detecting vacuum/pressure. Vacuum switches and sensors are safety devices that are monitoring air pressure. Any air pressure loses or blockages can trip these safety sensors and shut down your auger feed motor. When inspecting or replacing a vacuum switch, be sure to check the hose/tubing and replace if there are signs of notable wear. Learn more about vacuum/pressure switches in our below video.

Harman Oakleaf, TL2.0, and TL2.6 woodstove models will use a 110 degree snap switch (also referred to as a low limit switch), as the blower control switch, part 3-20-408412. This switch detects the heat during the start-up period and will lock in once it reaches the determined temperature allowing the blower fan to turn on. Harman SF1500A, SF2500A, SF2600SS, and SF3500A furnace models will have a blower fan limit switch, part 3-20-23139 mounted in the overhead plenum. This switch controls on and of sequences of your furnace blower based on the temperature points you set. Learn about about general limit switches in our video below.

Looking for a Harman coal or wood stove control board, switch, or sensor you can't find? Please contact us for inquires and requests!