FEATURES

• Two Mounting Configurations
  • Open Board With Stand-Offs - saves space and cost
  • Potted - protection for washdown and extreme vibration
• Multi Pin Connector - fast assembly
• 2 Trial for Ignition Options: 1 and 3 try
• 4 Trial for Ignition Times: 4, 7,10 and 15 seconds (customized timings available)
• 2 Flame Sense Options: single spark and sense and remote sense
• Thermostat/Power Off Reset

APPLICATIONS

• Commercial Cooking Equipment
• Ceramic Infrared Heaters
• Black Body Infrared Heaters
• Construction Heaters* * Line Polarity Insensitive designs available subject to minimum order quantities

DESCRIPTION

The 35-72 is a 120 VAC direct spark ignition control for controlling a gas valve and igniting LPor natural gas on heating equipment that provides a 120 VAC operating voltage.

The microprocessor circuit design provides precise, repeatable timing sequences for ignition times, purge times (pre- and inter-) along with multiple tries for ignition and flame sensing during pre-purge.

SPECIFICATIONS

THE TOTAL SOLUTION FOR GAS IGNITION CONTROL

Fenwal offers a complete range of ignition control products including:

• Ignition Controls
• Spark and Flame Sense Electrodes
• Spark and Flame Sense Cables
• Wiring harnesses

Designed, developed and manufactured by Fenwal, these components integrate seamlessly providing maximum system performance

Getting Started - Samples

To ensure proper system design and operation, Fenwal provides sample ignition controls, high-voltage wires and electrodes for trial and evaluation at no charge. To get you started quickly, Fenwal has identified our most popular ignition controls, see Page 8. Whether it is an individual control, complete start-up kit or customized control, Fenwal is ready to provide your gas ignition solution.

Fenwal Ignition Development Center

Send your equipment to us and we'll design, install and qualify a control to meet your exact application requirements. Fully equipped and staffed with trained technicians, the Fenwal Ignition Development Center has proven extremely beneficial for many customers focused on product quality and reducing time-to-market for their appliances.

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 TRIALMODEL

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 TRIALMODEL

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 TRIALMODEL

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 TRIALMODEL

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.

MOUNTING AND WIRING

The 35-72 is not position sensitive and can be mounted vertically or horizontally. The control may be mounted on any surface and fastened with #6 sheet metal screws. Secure the control in an area that will experience a minimum of vibration and remain below the maximum ambient temperature of 80C (175F).

All connections should be made with ULapproved, 105C rated, 18 gauge, stranded, 0.054 in. thick insulated wire. Refer to the appropriate wiring diagram when connecting the 35-72 to other components in the system. High voltage spark cables and control wiring harnesses are detailed on Pages 5 and 6.

SINGLE SPARK AND SENSE

REMOTE SENSE

Terminal Designations