Operation; System Operation With S8600 - Honeywell VR8304 Manual

The VR8300 gas controls provide ON-OFF manual
control of gas flow. In the OFF position, pilot and main
burner gas flow is prevented. In the ON position, pilot and
main burner gas flow is under control of the thermostat, the
intermittent pilot module, and the two automatic main
valves.

SYSTEM OPERATION WITH S8600

When the thermostat calls for heat, the S8600 Inter­
mittent Pilot Module is energized. The S8600, in turn,
activates the first automatic valve of the gas control. Pilot
gas flow is allowed. Simultaneously, the S8600 module
generates a spark at the igniter-sensor and lights the pilot.
The pilot flame is sensed by the igniter-sensor, and spark
generation ends.
After the pilot is lit, the S8600 module energizes the
solenoid for the second automatic valve operator and gas
flow main burner is followed (the first automatic valve
remains energized). The second automatic valve dia-
NOTE, SECOND AUTOMATIC VALVE OPERATOR AND SERVO PRESSURE REGULATOR
SHOWN OUTSIDE GAS CONTROL FOR EASE IN TRACING GAS FLOW.
&
SLOW-OPENING GAS CONTROL HAS A GAS FLOW RESTRICTOR IN THIS PASSAGE.
FIG. 11-POSITION OF GAS CONTROL COMPONENTS DURING THERMOSTAT OFF CYCLE.
phragm, controlled by the servo pressure regulator, opens
and adjusts gas flow as long as the system is powered and
the pilot is burning. The servo pressure regulator monitors
outlet pressure to provide an even main burner gas flow.
Loss of power (thermostat satisfied) de-energizes the
S8600 module and closes both automatic valves. The
system is ready to return to normal service when power is
restored through the thermostat.
Loss of pilot flame, or flame too small to reliably light
main burner, closes the second automatic valve operator.
The S8600 module then attempts to restart pilot. On S8600
modules with lockout timers, the first automatic valve
closes after the lockout period. On S8600 modules without
lockout timers, the trial for ignition continues indefinitely
and the first automatic valve remains open.
H pilot flame is restarted successfully, main burner is
reopened, and gas flows to main burner as described
above. Gas control operation is described in more detail
below.
SECOND
AUTOMATIC
11
SERVO
/ PRESSURE
REGULATOR
12,3958
68-0108-1