SECTI
ON
3
: O
PER
AT
ION
27
H2O BOILER
HC SERIES IOM Manual
When the air pressure switch is closed and safety loop is satisfied, pre-purge will
start.
Blower continues to run at its maximum frequency for a period identified as the
purge time.
3.1.3
Pilot Flame
After completion of the pre-purge period, the burner controller sends the required
voltage to the ignition rod, and 120V to the two, pilot safety shut off valves. The
valves open simultaneously with the activation of the ignition rod. Upon pilot
ignition, and after the flame is detected by the sensor, the ignition rod will be
deactivated.
If after 5 seconds activation of the flame rod and opening of the gas valves, pilot
flame is not established and detected by the flame sensor, the gas valves will
immediately shut down and the boiler/water heater goes into the “lock-out” mode.
The unit will not re-start until the burner controller is manually reset.
3.1.4
Main Flame
Once pilot flame is established burner controller will send 120V to the two main
safety shut off valves. From these valves, gas flows into the gas butterfly valve.
Air supplied by the blower flows through to the burner head where it mixes with
gas and the air/gas mixture is ignited.
The pilot safety shut of valves will open five seconds after the main safety valves
are closed. If at any time during the operation flame (pilot or main) is not detected
the boiler/water heater will immediately shut down and will not restart until the
burner controller is manually reset.
D-VAC Sales Inc. Email: dmann@dvachvac.com Tel: (516) 256-3131 www.dvachvac.com
