Lochinvar FTxl 500 Service Manual page 22

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Service
Functions
Service Mode Delay
By pressing the pin button on the front of the display for
five (5) seconds, the control will be placed in Service Mode.
This will override all other heat demands. The Service Mode
allows the installer to set the unit to any firing rate for the
purpose of combustion analysis. The delay sets the length
of time the boiler will stay in the Service Mode if no keys
have been pressed before going back to its original state.
This parameter can only be changed by the installer by
accessing the Service Mode Delay parameter. The time range
of this parameter is 1 to 10 minutes. The default value is 10
minutes.
Freeze Protection Pump On
The SMART SYSTEM control will turn on the boiler and
system pump outputs whenever the inlet temperature
drops below this setting.
water in the heat exchanger from freezing. Certain low-
temperature applications (such as snow melt) can operate
at temperatures around freezing, so this setting needs to
be lowered in these cases. The installer can adjust the
temperature at which the pump outputs are turned on by
accessing the Freeze Protection Pump On parameter. The
minimum setting is -3°F (-19°C), and the maximum setting
is 45°F (7.2°C). The default setting is 45°F (7.2°C).
Freeze Protection Burner On
If running the pumps does not prevent the inlet temperature
from falling closer to freezing, the SMART SYSTEM control
will fire the burner at low fire. The installer can adjust the
temperature at which the burner fires by adjusting the Freeze
Protection Burner On parameter. The minimum setting
is -3°F (-19°C), and the maximum setting is the Freeze
Protection Pump On parameter. The default setting is 37°F
(2.8°C).
Freeze Protection Burner Differential
Once the burner has started firing due to a low inlet
temperature, the inlet temperature must increase by this
amount before the burner turns back off. The installer can
adjust this differential by accessing the Freeze Protection
Burner Differential parameter. The minimum setting is 0°,
and the maximum is 20°F (11°C). The default setting is 5°F
(2.8°C).
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This is done to prevent the
Service Manual
DHW Settings
DHW Tank Set Point
By installing a tank sensor, the SMART SYSTEM control can
perform the tank thermostat function. The SMART SYSTEM
control automatically detects the presence of this sensor, and
generates a DHW call for heat when the tank temperature
drops below the tank set point differential (Tank Set point
Differential parameter), and finishes the call for heat when the
tank temperature reaches tank set point. This parameter can be
changed by the installer by accessing the DHW Tank Set point
parameter. The temperature range of this parameter is from the
tank minimum set point to the tank maximum set point. The
default value is 120°F (49°C).
Tank Set Point Differential
When a tank sensor is installed, the tank temperature must drop
this amount below the tank set point (DHW Tank Set point
parameter) before the boiler turns back on. The installer can
adjust this setting by accessing the Tank Set point Differential
parameter. The minimum setting is 0° (0°C), and the maximum
is 40°F (22°C). The default setting is 6°F (3°C).
DHW Boiler Set Point
When a DHW call for heat becomes active, the control will
use the DHW boiler set point to determine the firing rate of
the boiler based on the boiler outlet water temperature, or
system temperature when DHW is programmed as a zone.
This parameter can be changed by the installer by accessing the
DHW Boiler Set point parameter. The temperature range of this
parameter is 68°F (20°C) to 190°F (88°C). The default value is
180°F (82°C).
DHW Boiler Offset
This parameter reflects the degrees above DHW boiler set point
the temperature has to go before the boiler will shut off. The
range is 0°F (0°C) to 20°F (11°C). The default setting is 5°F
(2.8°C).
DHW Boiler Differential
This parameter reflects the degrees below DHW boiler offset
set point the temperature has to go before the boiler turns back
on. The range is 0°F (0°C) to 60°F (33°C). The default setting
is 10°F (6°C).
DHW Recirculation Pump Offset (Recirculation Pump)
The SMART SYSTEM control will turn the DHW recirculation
pump on when the DHW return water temperature drops
below the DHW Tank Set Point minus the DHW Recirculation
Pump Offset. The range for this parameter is 0° to 54°F (30°C).
The default value is 10°F (5°C).
DHW Recirculation Pump Differential
Once the SMART SYSTEM control turns the DHW recirculation
pump on, the DHW return water temperature must increase by
the DHW Recirculation Pump Differential before the control
turns the DHW recirculation pump back off. The range of this
parameter is 0° to 90°F (50°C). The default value is 5°F (2°C).