PEERLESS PureFire PF-200 Installation, Operation & Maintenance Manual page 47

The default for these values are as follows:
Temp = 18°F and Time = 20 minutes.
This function is designed to help the boiler recover
from a setback condition. It will also help if too low of
a value is chosen for the boiler design and/or mild
weather temperature.
This value will continue to increase by the Temp value
if the demand continues through consecutive Time
periods.
The value is allowed to exceed the design temperature
but can never exceed the boiler maximum temperature.
NOTICE
If thermostat terminals #1 & #2 are installed with a
permanent jumper in CH mode 1, Thermostat and
Outdoor Reset, the boiler target will eventually reach
and remain at Boiler Maximum indefinitely even with
Boost Temp and Time set to 0. In this case CH mode
2 would be a better choice for Permanent Demand
with Outdoor Reset.
Warm Weather Shutdown: In any CH mode utilizing
outdoor reset, the warm weather shutdown feature
prevents the boiler from operating if the outdoor
temperature (read from the outdoor sensor) exceeds
the selected value. The default value for Warm
Weather Shutdown is 70°F (21°C).
Figure 8.3 shows a graphical representation of this value
(vertical line) at 75°F outdoor temperature. This feature
only affects CH demands. The boiler will operate for
DHW demands regardless of outdoor temperature.
Figure 8.3: Outdoor Reset Operation
BOILER CONTROL: INTERNAL WIRING & OPERATION
4. Other Features:
Pump Post Purge: The P
installer to set post purge times for the CH and/or
General Pumps. The circulator will continue to run for
the time selected after the call for heat has ended.
These values are settable from 0 to 900 seconds and
the factory default is 60 seconds.
Ramp Delay Step Modulation: This feature is useful
for systems with very small zones which can cause a
boiler to short cycle. The Ramp Delay Step
Modulation function only applies to Central Heating
and is not applied to DHW demands.
After the ignition sequence, the control modulates
down to 20% of input. Then the input rate is gradually
increased until the supply temperature approaches its
target. At this time, the control modulates normally.
Anti-Cycling: The P
installer to set a minimum off time to prevent short
cycling of the boiler. This only affects short cycling
due to reaching the temperature limit setpoint. If the
CH or DHW demand cycles, the control will cycle to
match the demand.
The minimum off time can be set from 0 to 15 minutes
in 1 minute increments. It has a default of 3 minutes.
The value for "TDiff" is the difference in temperature
between the supply temperature and the target
temperature that will override the minimum off time.
This temperature difference indicates the presence of
a substantial heat load.
The default value for TDiff is 30°F and can be set to
values between 20°F and 40°F. TDiff can also be
disabled by choosing "Off". To do this push the down
arrow until "Off" is displayed.
F ® control allows the
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F ® boiler control allows the
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