Garland AIR-DECK GAS BAKE AND PIZZA OVENS - Manuel (Page 13)

Part # 1382670 (12/07) Page 13
INTERMITTENT PILOT INSTRUCTIONS - HONEYWELL S286
Lighting and Shutdown Instructions
Starting Burner
1. Turn the gas valve control knob to “OFF” wait five
minutes.
2. Turn gas valve control knob to “ON”.
3. Turn power switch to “ON”, fan will turn on.
4. Turn thermostat to desired temperature setting.
5. If the burner does not light, turn the thermostat to “OFF”
and wait five minutes then repeat step (4).
Shutting Burner Down
1. Turn thermostat to “OFF”.
2. Turn power switch to “OFF”.
3. Turn gas valve control knob to “OFF”.
4. Turn main shutoff valve to “OFF”.
Operation
First Stage – Trial for Pilot Ignition
On every call for heat (system start), the S86 performs an
internal safe-start check shows that a flame-simulating
condition is present.
During a normal start, the S86 opens the first operator in
the gas control. This allows gas to flow to the pilot burner.
Simultaneously, the electronic spark generator in the S86
produces a 30,000 volt spark pulse output. This voltage
produces a spark at the pilot burner ignitor/sensor rod,
igniting the gas flowing around the electrode. If the pilot
flame is not detected during the trial for pilot ignition, the
S86A and B will continue trying for pilot ignition until a flame
is established. The S86C and D contain a safety lockout timer
to limit the trial for pilot ignition period.
Second Stage – Main Burner Operation
When the pilot flame is established, a flame rectification
circuit is completed to the burner ground. The S86 flame
sending circuit detects the flame current and shuts the
spark generator off. At the same time the second operator
(main) is opened in the gas control, allowing fast flow to
the main burner. The pilot flame ignites the main burner
conventionally. On the S86C and D the flame current also
holds the safety lockout timer in the reset, or normal,
operating condition.
Safety Lockout Time (S86 & S86D Only)
The safety lockout timer circuit starts timing the moment
the trial for pilot ignition starts. When the timing period runs
out, the trial for ignition ends, and the control module goes
into lockout. Before another attempt to start can be made
the S86 must be reset. Reset by adjusting the thermostat or
controller below room temperature, or to its “OFF” position.
An alternate method is to shut the system power “OFF”. If
normal ignition does not occur, use the trouble shooting
table to determine the problem.
Service
Preliminary Check
The following visual checks should be made before trouble
shooting and after installation of maintenance.
1. Check power to appliance and S86
2. Manual shutoff cocks in gas line to appliance must be
open.
3. Make certain all wiring connections are clean and tight.
4. S86C & D module must not be in safety lockout. First de-
energize the system and wait at least one (1) minute. This
resets the module allowing a return to start condition.
Then energize the system.
5. Review the S86 system normal sequence of operation.
S86 Checkout And Trouble Shooting
NOTE: On servicing S86A, B, C and D models.
The S86E, F, G and H models can be used to directly replace
S86A, B, C and D models (E replaces A model, F replaces B, G
replaces C model and H replaces D model) and the S86B and D
can be used to replace S86F and H, respectively. However, the
S86A and C cannot be used to replace the S86E and G module
on IPI systems that use VR8520 gas controls. VR8440 or VR8520
valves will not function properly with the S86A or C.
Check Grounding
A common ground is required for the pilot burner, the
ignitor-sensor, the GND terminal of the S86, and the main
burner. The main burner generally serves as the common
ground. If the ground is poor or erratic, safety shutdowns
may occur occasionally even though operation is normal at
the time of the checkout. Therefore, if nuisance shutdowns
have been reported, be sure to check the grounding.