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GT INSTALLATION AND OPERATION INSTRUCTIONS Page 27
Figure 38 - Input Conversion Chart
Setting Sentry 2100T control
Programming is accomplished by a series of three push
buttons located on the bottom side of the control. To
enter the programming mode, press the function key
once, “RUN” should be displayed on the screen. To scroll
through the various menu options depress ↑. To alter the
value of a menu option press “Function” once while the
menu option is displayed, and the current value will be
displayed, then use ↑ for up, and ↓ for down, until the
desired value is obtained. To enter the selected value
press “Function”, which will return to the menu and store
the new setting. When all desired values are set, scroll to
the “RUN” menu option, and press Function, which exits
the Programming Mode and initiates normal operation.
If the control is left in the Program Mode longer than 30
seconds without receiving any input the unit will turn off.
Press “Function” once to continue programming or to
restart boiler operation.
Below is a list of functions and a description of what
they control:
RUN - Stores Values & initiates
LO - Boiler Setpoint for DHW, 80 - 200°F, 27 - 93°C
HI - Boiler Setpoint for Heating, 80 - 200°F, 27 - 93°C
DIF - Differential, 1 - 40°F, -17°C - 4°C
RES - Sets Outdoor Reset Curve Slope,
70°F, 21°C to HI
SFS - Sets Starting Gas Input Value, 60 to 100
GT150 & 200 is 60 to 100
GT-400 is 45 to 90
HFS - Sets Highest Gas Input Value, 100 to 240
GT-150 & 200 is 100 to 240
GT-400 is 90 to 195
LFS - Sets Lowest Gas Input Value, 40 to 100
GT-150 & 200 is 40 to 100 (see note)
GT-400 is 35 to 90
NOTE: LFS must not be set below 48 on the GT150
model. To start the control operation return to
“RUN” on the menu and press “Function”. Normal
operation will begin.
Recommended Settings
When programming the Sentry 2100T determine
what the hottest boiler temperature required for the
coldest day will be. This will be the HI SETTING. If
an indirect tank is used for domestic hot water, DHW,
determine the minimum boiler temperature required
to ensure an adequate supply of hot water. This is the
LO SETTING. The LO SETTING is only used during
a call for DHW, when A and C terminals are closed.
Set the LO to the temperature required for the Indirect
Water Heater. 140 °F, 60°C or at least 30°F, -1°C higher
than the indirect Aquastat is recommend.
WARNING: Proper control settings must be used
to prevent water supplied for domestic use from
exceeding 130°F, 54°C or a scald injury will occur!
When higher water temperatures are required
for appliances such as a dishwasher, a mixing
valve or some other tempering means must be
installed. Households with small children may
require water temperatures less than 120°F, 49°C.
Local codes must be complied with!
Table 6 - Recommend System Temperatures
Hi Dif RES
System °F, °C °F, °C °F, °C
Finned Tube Baseboard 190, 88 20, 11.7 85, 29
Cast Iron Radiators 150, 66 20, 11.7 85, 29
Radiant 130, 54 20, 11.7 85, 29
Outdoor Sensor (10K)
The outdoor sensor should be installed to take advantage
of the energy saving features of the Sentry Controller.
Install the sensor on the north, or coldest side of the
building out of direct sun. It must be at least 10 ft, 3 m
from the vent terminal or other source of heat.
Display Data - Input conversion chart
0
50
100
150
200
250
300
350
400
240 215 190 165 140 115 90 65 48 40
LED Display
)s'000( UTB
GT-150 GT-200
GT-400