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OPERATING INSTRUCTION
WARNING! This automatic control is more simply stated as an automatic switch. The control merely
switches the heater on and off. It does NOT adjust the heater gas pressure to changing ambient
temperatures or changing airflows. This is YOUR responsibility!
The thermostat is programmed at the factory to operate with your heater. It will hold this programming
even when the power is shut off to the unit. The only change you will need to make to the control will be
if you need to change the temperature. You must follow these instructions to do so.
The heater is set at the factory to operate at 100 degrees (F). When the air in the bin plenum is below 100
degrees, both the low-fire and high-fire solenoids are activated. When the temperature in the plenum rises
to 100 degrees, the high-fire solenoid is shut off, leaving the low-fire operating alone. When the air
temperature falls to 97 degrees, the high-fire comes back on, the cycle repeats.
IMPORTANT: The low-fire solenoid is also controlled by the thermostat. It operates as a high-limit for
the system and is set 10 degrees ABOVE the high-fire set point. This way, if conditions change and the
low-fire alone is able to heat the air above 100 degrees, it will shut off at 110 degrees. And neither
solenoid will be activated until the air temperature falls to 95 degrees, at which point both solenoids will
reactivate. Changing one thermostat setting, therefore, requires setting both.
Setting the thermostat:
1.
Turn off the gas supply to the heater and let all gas in the heater burn out. The heater must be
connected to power with the switch in the “On” position. This may be best done by connecting to an
extension cord, rather than having the fan running, but there must be no gas in the heater plumbing to
ignite!
2.
Press the button marked “MODE”. Display will show “SP1”. Press “MODE” again and the display
will flash the current set point (110 from the factory).
3.
Use the “UP” or “DOWN” arrow keys to set this value 10 degrees above your desired operating
temperature; for example, if you want to maintain 150 degrees, you will need to set this value at 160
degrees. When the unit displays the correct temperature, press the “ENTER” button. The display will
show the new temperature without flashing.
4.
Press the button marked “MODE” again. Display will show “SP2”. Press “MODE” again and the
display will flash the current high-fire set point (100 from the factory).
5.
Use the “UP” or “DOWN” arrow keys to set this value to your desired operating temperature; for
example, if you want to maintain 150 degrees, you will need to set this value at 150 degrees. When
the unit displays the correct temperature, press the “ENTER” button. The display will show the new
temperature without flashing.
6.
Press the “MODE” button again to exit. For a few seconds the screen will go blank, and then will
display the current ambient temperature. There is no further programming to be done, or available, or
in any way productive, outside of the temperature setting outlined in the above procedure.
WARNING: If you used an extension cord to power the unit for setting purposes, you now MUST plug
the heater back into the fan controls, thus interlocking the two unit’s power. This is your number one
way to prevent a fire.
