Submittal Sheet

ManualsBrandsFenwal ManualsHeating SuppliesDirect Spark Ignition Control, 120v w/ 0 sec. Prepurge (4 sec TFI)

Start up - Heat Mode

When the thermostat is set above the ambient temperature,

120 VAC are supplied to the L1 terminal. When this occurs the con-

trol will power up and perform a self-check routine and begin a pre-

purge*, if selected. Following the pre-purge, the gas valve is ener-

gized and sparks commence until flame is detected

or the Trial For Ignition (TFI) period expires.

When flame is detected, the spark is shut off and the gas valve

remains energized. The thermostat and burner flame are

constantly monitored to ensure that the system is functioning prop-

erly. When the thermostat is satisfied and the demand for heat

ends, the gas valve is de-energized immediately and the flame is

extinguished.

System Response to Flame Failures

The robust design of our gas ignition controls is demonstrated

by their ability to respond to flame failures in a safe manner

and provide re-ignition options for the equipment designer.

Flame Failure During

Trial-for-Ignition Period

SINGLE TRIAL MODEL

Should the burner fail to light or flame is not detected

at the end of the trial-for-ignition period, the gas valve is

de-energized immediately and the control will go into

lockout mode.

MULTI TRIAL MODEL

Should the burner fail to light or flame is not detected

during the first trial for ignition period, the gas valve is

de-energized and the control starts the inter-purge

sequence before another ignition attempt. After inter-purge,

the control will attempt two additional ignition trials.

If these attempts are unsuccessful the control will go into

lockout mode.

Flame Failure of Established Flame

RE-IGNITION

If the established flame signal is lost while the burner is

operating, the control responds and begins sparking within

0.8 seconds. The spark will be energized for the duration

of the trial-for-ignition period in an attempt to re-light the

burner. If flame is re-established, normal operation resumes.

SINGLE TRIAL MODEL

If the burner does not light after the first attempt, the

control will de-energize the gas valve and go into lockout

mode. See Lockout Recovery

MULTI TRIAL MODEL

If the burner does not light after the first attempt,

the inter-purge sequence is completed between attempts

to re-light the burner. If the burner fails to light after the

third try, the control will de-energize the gas valve and go

into lockout mode. See Lockout Recovery

Lockout Mode (On-Board Safety System)

After single or multiple attempts to light the burner have failed or

flame is not established, the control automatically enters lockout

mode. The control will not open the gas valve unless there is

intervention by the user. See Lockout Recovery.

Lockout Recovery

For lockout recovery, reset the thermostat below ambient tempera-

ture or remove the 120 VAC power supply for 5 seconds.

SEQUENCE OF OPERATION / FLAME RECOVERY/ SAFETY LOCKOUT

Page 2 Series 35-72, 120 VAC Direct Spark Ignition Control

* The pre-purge is simply a delay to allow gas to dissipate from the

combustion chamber. This control is not equipped with a combustion blow-

er relay and therefore does not initiate a fan powered pre-purge.