Sequence Of Operation - HELIX VX-399 Installation, Operation & Maintanance Manual

1.4 Sequence of Operation

Operational State
No
Heat
Demand?
Yes
DHW CH
Pump on
No
Supply
Temperature
<Setpoint?
Yes
15 Second
Prepurge
Ignition
Sparking
After 2 seconds
APPENDIX A - CONTROL MODULE
User Interface Display
67
Explanation
Boiler operates in standby mode
until demand for Central Heat (CH)
or Domestic Hot Water (DHW) is
detected.
CH or DHW pump is turned on based
on type of heating demand.
(CH call is illustrated)
General boiler pump is activated for
any heat call.
Control Module compares supply
Temperature to set point. Boiler
proceeds to ignition if supply
temperature is less than set point.
Combustion Air Blower speed
modulates to pre-purge setting for 15
seconds.
Sparking initiated sequence.
P/N 240010943, Rev. C [09/07/2016]