Lochinvar HERALD HCB116CE, Installation Manual

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6
If flame is not detected after spark ends the control will
perform a post-purge, then start another pre-purge cycle
and try to light the boiler again.
7
If the flame is detected it holds the firing rate steady for a
few seconds then begins to modulate the firing rate based
on a set point or some other command (such as the 0-10v
signal)
8
If a space heating call for heat is active and the tank
thermostat or sensor starts a DHW call for heat, the boiler
will switch to the DHW mode. The DHW pump will turn on
first then the boiler pump will turn off this will divert the
water to the indirect tank coil. The control will modulate to
maintain the DHW set point.
9
If the boiler is not part of a Cascade and both heating and
DHW calls for heat remain active for long enough the boiler
will switch back and forth between the 2 modes until either
heating or the DHW load is satisfied.
10
Once both calls for heat are satisfied the control will turn off
the burner. The fan will continue to run during the post-
purge period.
11
Any pumps that are running will continue for their
respective pump overrun time period before switching off.
A 60 second anti-cycle period will start which will delay any
call for heat.
12 In standby ready to start a new cycle.