Harman PF100/120 Pellet Furnace Wall Thermostat. #3-20-08101 Harman

Replacement wall-mounted thermostat for Harman PF100 Pellet Furnaces.

Wall Control

The wall control acts like a thermostat, a thermistor in the wall control is sending temperature information back to the microprocessor on the furnace. This information is used to determine the need to increase or decrease the size of the fire according to the temperature demand.

Setting The Room Temperature

To set the room temperature, simply turn the temperature dial to the desired setting. The control and the furnace will then perform to achieve the set temperature. Note: The minimum temperature you can set with a full counter-clockwise knob position is 58 degrees. The maximum temperature you can set with a full clockwise knob position is 90 degrees.

Wall Control calibration

The “Normal Setting” on the Temp Dial of the Furnace Control (See Fig.44) calibrates the Wall Control temperature span. If the Temp Dial is not pointing to the “Normal Setting”, the temperature span could vary by 3 degrees up or down depending on the Temp Dial knob setting.

Low Fuel Sensor

There is a low fuel sensor in the hopper that tells the control that the fuel level in the hopper has dropped below the sensor. When this happens, the Low Fuel light on the Wall Control will start to blink. You then know that it is time to fill the hopper with pellets.

Note: Testing the low fuel sensor can be done by turning the FEED ADJUSTER knob to “Test”. The POWER light will go off when the sensor is uncovered and will light when the sensor is covered again.

Note: The LOW FUEL light on the Furnace Control will light at the same time. Only the LOW FUEL light on the Furnace Control will remain lit for three minutes after the sensor is covered with pellets. See Note below.

Note: The Low Fuel light indicates that there is power going to the auxiliary leads in the circuit breaker junction box. (120 VAC 60 Hz Max. 1 Amp.)The auxiliary power leads could be used if a bulk hopper and auger system were installed. (see wiring diagram on page 36)

Type of Fuel

Pelletized wood only.

Note: The lower the ash content of the pellets means less heat exchanger surface cleaning that will be needed. The cleaner these surfaces are kept, the more efficient the furnace will be.