Crown Boiler Phantom X series, Installation And Operating Instructions Manual, Page: 92 / 136

92
X. Operation
F. Changing Adjustable Parameters (continued)
The Control is shipped with defaults that will provide improved operation. Adjustment is only required to optimize
setup.
The expected heat rate adjustment is used to better match boiler output to the home heating needs. After receiving
a "call for heat" the Control first uses the expected heat rate value to set a maximum heat rate. The maximum heat
rate is the highest heat rate that the boiler can fire to at that moment. The maximum heat rate is the summation of
the expected heat rates for the active (turned on) zones. After establishing the maximum heat rate the Control then
measures water temperature and fires the boiler only as hard as required for the heat demand.
Expected Heat Rate Adjustment Screens (Zone Panels with HeatMatch Software Only)
Figure 56: Four Zone House (with Zone Control Connected)
Maximum Heat Rate:
Automatically adjusted
by the Control based on
the size and number of
zones calling for heat.
Example “call for heat”
durations for a four zone
house.
Maximum heat rate limits
firing rate and prevents
the Control from firing to
100% in response to a
smaller zone demands.
Actual Heat Rate:
Boiler is free to
modulate based on
temperature from
minimum to maximum
heat rate .
Figure 57: Expected Heat Rate Adjustment (with Zone Control Connected)
NOTE
This feature requires Zone
Control to be connected.
Refer to Electrical section
for Zone Control connection
information.
The sum of Zone Expected
Heat Rates plus DHW
Maximum Expected Heat Rate
(if DHW is active) is used to
calculate the active maximum
modulation rate.
Maximum modulation num -
bers are shown in both RPM
and kbtu/hr to allow for easier
understanding of boiler heat
rate.