21
Guardian LP or Natural Gas Heater
Ignition Control
The control sends and receives voltages to operate
or verify operation of components. Refer to the
following and Fig. 24 or 25 to understand the ignition
control's terminal designators if doing voltage checks
on the control.
IND: 120 VAC from control to motor
L1: 120 VAC power to control
LED (AD Models):Connection for diagnostic light
HSI (AW models): 120 VAC from control to hot
surface igniter.
HSIG (AW models): Neutral return of igniter
L2 (AW models): Neutral of control
MV or GV: 24 VAC from ignition control to high limit
switch and then to gas control valve.
W: 24 VAC input from transformer (without this volt-
age the ignition control will not function).
PSI or PS1: 24 VAC from ignition control to air prov-
ing switch.
PSO or PS2: 24 VAC from air proving switch to
ignition control.
FSI or FS: Micro amperage from control to flame
sensor for proving burner flame.
FSG (AW models): Ground of flame sensor
C or COM: Control and burner ground
R or X (AD models): No terminals
Also refer to "Operation Sequence" within this manual
as needed to understand operation of the ignition
control during a call for heat.
Ignition Control (DSI)
Ignition Control (HSI)
FIG. 24 (Model AW)
FIG. 25 (Model AD)
Owner's Manual • Guardian