Instructions and diagrams for modifying DuoTherm® 900/9000 series OR any furnace that is controlled by the themrostat in the ground circuitry, for the purpose of using a Fan 50 Plus Pins, Fan 50 Plus or TDR

PLEASE NOTE: The documents provided here as a courtesy. By downloading and or implementing the wiring diagrams/schematics given here you accept full responsibility for any modifications made using them. Only qualified service technicians should attempt to modify the control circuitry in a furnace. Improper modification of the furnace can cause serious injury or death.

*** Use these diagrams and information provided in them at your own risk! ***

Modification instructions for the Fan 50 Plus and Fan 50 Plus Pins

Please use the link below for using a Fan 50 Plus or Fan 50 plus pins in a 900 / 9000 /66000 / 66100 series Duo Therm furnace or ANY other furnace that uses a DSI ignitor board and time delay relay where the thermostat comtrol is in the ground circuitry.

For using a Fan 50 Plus and Fan 50 Plus Pins Duo Therm DSI model furnaces (PDF)

Modification instructions for the using the TDR in a Duo Therm direct spark igntion furnace

The link below for is for using a TDR in a 900 / 9000 / 66000 / 66100 series DuoTherm® furnace or any other direct spark ignition furnaces that uses a time delay relay where the thermostat control is in the ground circuitry.

For using the TDR in DSI model Duo Therm furnaces (PDF)

Modification instructions for using the TDR in Duo Therm pilot model furnace

The link below for is for using a TDR in 66000 / 66100 series DuoTherm® pilot model furnace that uses a time delay relay where the thermostat control is in the ground circuitry.

For using the TDR in pilot model Duo Therm furnaces (PDF)