L.B. White Oval 80™ Radiant - Manual (Page 20)

IGNITION CONTROL
The ignition control monitors the operation of the
heater. It starts the fan motor, identifies air pressure
switch operation, and powers the spark igniter and gas
control valve.
The control incorporates diagnostics which are provided
to the red LED on the burner box door. Any malfunction
of the heater is identified by a flash sequence provided
by the LED.
Both 115 VAC main power supply and 24 VAC from the
transformer are required for operation. If 24 VAC is not
delivered to the control, it will not function.
There are no serviceable parts in the controller. To
replace the controller, use a 5/32 allen wrench to
remove the mounting screws
FIG. 26
The air differential pressure switch is a safety device.
If its contacts do not close or are stuck closed during
a call for heat, the controller will not allow ignition to
occur. The igniter will not spark nor will the gas control
valve open.
For proper heater operation:
■ Ensure the air inlet to the burner box is not blocked or
flex duct kinked.
■
Burner box gasketing must be in good condition.
■
The copper pressure tube on the burner must be free
of blockages. See Fig.27.
■ Ensure the flexible tube is free of dust and securely
connected to the copper tube at the burner and to the
fitting at the differential pressure switch. See Fig.28.
■
The air differential pressure orifices should be free of
blockages. If cleaning is required use pressurised air:
Orifices on pressure switch (See Fig.27)
-- Remove respective orifice from switch.
-- Hold up to light, if blocked, clean the orifice with air.
-- Ensure orifices are securely pushed backed into
proper location on switch.
Servicing the differential air pressure switch:
■ The differential pressure switch is not adjustable. If the
switch does not make the circuit after inspection of air
inlet, gasketing, tubes, and orifices, it must be replaced.
■
Do not jumper the switch. Doing so will cause lock-out of
the heater’s ignition control.
FIG. 27
AIR DIFFERENTIAL PRESSURE SWITCH,
TUBING & PRESSURE ORIFICES
SWITCH
ORIFICES
GREEN BLUE
FLEXIBLE
TUBE
COPPER
TUBE
20