Crown Boiler PHNTM080 - Page 107

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5) Modulation Status Screen:
a) Fan Speed - Current actual fan speed in RPM
b) Setpoint - Current target fan speed in RPM
c) Speed Control-Indicatesthefunctioncurrentlycontrollingfanspeed(andthereforeringrate).Typicalpossibilities
include:
• Off - Blower is off.
• Burner system - The blower speed is being determined by that needed for pre-purge, ignition, or post purge.
• Demand - Fan speed is being determined by the “PID” function in the control. This function regulates the fan speed
based on a combination of past and present differences between the target water temperature and the actual water
temperature.
• Supply Limit - The supply temperature is above 185°F and the input is being limited to reduce the likelihood of
high limit activation.
• Delta-T limit - The temperature rise across the boiler has exceeded approximately 54°F and the input is being
limited to reduce the likelihood of a soft lockout.
• Stack Limit-Theuetemperatureisabove200°Fandtheinputisbeinglimitedtoreducethelikelihoodofahard
lockout.
• Min Mod - The input is not allowed to go lower because the minimum allowable fan speed has been reached.
• Manual - The boiler is set in manual input mode (see Settings Menu).
d) Modulation Source - Should always read “Local Mod. Control” in the applications covered by this manual.
6) Pump Status:
a) Boiler - Indicates whether the boiler pump is currently powered.
b) System - Indicates whether the system pump is currently powered.
c) DHW - Indicates whether the DHW pump is currently powered.
7) Boiler Demands:
a) Central Heat T’Stat - Indicates whether the boiler is seeing a call for space heat from a thermostat.
b) DHW T’ Stat - Indicates whether the boiler is seeing a call from a domestic hot water thermostat.
c) Frost Protection - Indicates whether the boiler is seeing a call for frost protection. This demand should never be present
unless the boiler supply, or header, temperature is at or below 45°F.
8) Outdoor Reset Screens(onlyvisiblewhenoutdoorresethasbeenenabledinCongurationMenu):
a) Outdoor - Current temperature at outdoor sensor.
b) Setpoint - Current CH setpoint obtained from outdoor reset curve (Figure 12.6).
c) Supply (or Header) Temperature - The actual water temperature at the current setpoint location (either the boiler
supplyorheader,dependingonthedemandandwhatsetpointlocationwasselectedintheCongurationMenu).
d) Outdoor Reset Graph - Shows all outdoor reset curve settings, the current outdoor temperature, and setpoint. Note: this
graph is for reference only and does not scale.