Gas-Fired Products N7/L7, 100, 40, 150, 175, 200 manual Sequence of Operation

19.0) SEQUENCE OF OPERATION

The chart below shows the sequence of operation for the normal operating cycle of the PTS/PTU when connected to a permanent 120V power supply and the heater is turned on and off by a remote 24V thermostat. (Electrical connection diagram B).

Thermostat low fire

Thermostat high fire

Blower

Air switch

Red power light

Ignition

Gas valve low fire

Gas valve high fire

Flame sensing

Amber valve light - low fire Amber valve light - high fire

Call for heat, Thermostat on 15 secs pre-purge

15 secs trial for ignition

Normal high fire operation flame sensing

Thermostat - high fire off Thermostat (turn off)

30 secs post-purge Heater OFF

T0 T1 T2 T3

Function ON

T4	T5	T6	T7	T8
Function OFF

If the flame is not sensed during sequence T3 then the burner will automatically begin re-ignition sequence T2. The ignition sequence will be repeated three times with a 60 second inter-purge. If the flame is not re-established the heater will go to lockout.

	Form #43343530
–40–	JJuly 08