The VR8205;VR4205 gas controls provide ON-OFF
manual control of gas flow. In the OFF position, gas flow to
the main burner is mechanically blocked. In the ON position,
gas flows to the main burner under control of the
thermostat, the direct ignition (DI) module, and the two
automatic main valves.
SYSTEM OPERATION WITH MODULE
When the thermostat calls for heat, the DI module is
energized. The module activates the first and second automatic
valves of the gas control, which allow gas to flow to
the main burner. At the same time, the DI module generates
a spark at the igniter-sensor to light the main burner.
The second automatic valve diaphragm, controlled by
the servo pressure regulator, opens and adjusts gas flow as
long as the system is powered
. The servo pressure regulator
monitors outlet pressure to provide an even flow of gas to
the main burner. Loss of power (thermostat satisfied) deenergizes
the DI module and closes the automatic valves.
The system is ready to return to normal service when power
is restored through the thermostat.