SP745 ROBERTSHAW REPLACEMENT MODULE

The Robertshaw SP745 780-845 work in the following series:

When the thermostat calls for heat, the 780-845 control simultaneously initiates ignition sparking and opens the pilot valve portion of the gas valve. Pilot flame recognition stops ignition sparking and opens the main valve portion of the gas valve. Pilot burner flame is continuously monitored at a synchronous frequency for the duration of the heating cycle. Should the pilot flame fail during the heating cycle, the control will shut off the main valve until the pilot flame is established.

The 780-845 lockout ignition control provides 90 seconds of spark, followed by a 6 minute time delay (purge) between ignition attempts.
After three tries, if no pilot flame is sensed, the control goes into a one-hour lockout period. At the end of the lockout period, if the demand for heat is still present, the unit will repeat the three tries for ignition.

During lockout, you may override the auto-system, and manually reset the unit at the thermostat.
The green diagnostic LED will be on continuously for normal operation.
The LED will be off for internal lockout and will flash continuously for problems external to the control (ie. not sensing flame).


Service Note:

The previous version of the SP745 part number 100-00826-** may not have used a sensing wire when use don the FMI and DESA fireplaces.
When replacing this series with the New Style SP745 the sense wire will need to be looped back to the new control module.

Gas Valve to Module Wiring:

(M) on gas valve to (MV) on Control Board.
(C) on gas valve to (PV/MV) on Control Board.
(P) on gas valve to (PV) on Control Board.

Transformer to Module Wiring:

Blue 24 Volt wire from Transformer to (TH/24V) on Control Module
Red Wire from Transformer to (TR-GRD) on Control Module (old style 14129 Transformers)
Yellow wire with Green ground lug to (TR-GRD) on Control Module (New style 14129 Transformers 2025)

     Use self tapping screw to secure ground lug to a clean location on the fireplace frame. 
      
Power to Transformer 110/120 Volt:
Black from power to Black Input to Transformer.
White from power to White Input to Transformer

Spark Plug:
Pilot Ignition wire will now move from (ING) location to the (Spark) location on the top of the control module.

Sense Wire:
If not used loop to E7 Terminal