Service manual

06/2010
Section 1. Definition of Terms
AutoCal –
A procedure by which the microprocessor in the heater accesses a stored calibration
table to convert gas flow to voltage to control the gas valve.
DSI (Direct Spark Ignition) – The circuit board that controls the ignition process. Once supplied
with 12 vdc by the main circuit board, it opens the gas solenoid, sparks the igniter, and senses the
flame. Also, during operation it continues to monitor the flame and will fire the igniter if flame
rectification is lost.
Ignition or minimum burn  The ignition gas flow and the lowest burn that the software will permit,
which is normally 15,000 – 20,000 Btu.
Maximum burn – The highest burn that will pass through the unit, normally 53,000 Btu.
T-in – The temperature measured at the entrance to the heat exchanger 1436
T-mid – The temperature measured near the center of the heat exchanger 2008
T-out – The temperature measures at the exit of the heat exchanger 1437
T-set – The stabilization temperature set by the pot on the circuit board 1841-RV