Install Instructions

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X. Operation F. Changing Adjustable Parameters (continued)
“Press” button to access the following parameters:
Factory
Setting
Range / Choices Parameter and Description
Enabled Enable Disable
Central Heat Outdoor Reset Enable
If an outdoor sensor is installed and Outdoor Reset is Enabled, the boiler will automatically
adjust the heating zone set point temperature based on the outdoor reset curve in Figure
45. The maximum set point is dened by the Central Heat Setpoint [factory set to 180°F
(82.2°C)] when the outdoor temperature is 0°F (-18°C) or below. The minimum set point
temperature shown is 130°F (54.4°C) [adjustable as low as 80°F (26.7°C)] when the
outdoor temperature is 50°F (10°C) or above. As the outdoor temperature falls the supply
water target temperature increases. For example, if the outdoor air temperature is 30°F,
(-1.1°C) the set point temperature for the supply water is 150°F (65.6°C).
Disable Do Not Calculate setpoint based on outdoor temperature
Enable Calculate the temperature setpoint based on outdoor temperature using a reset
curve dened by Low Outdoor Temp, High Outdoor Temp, Low Boiler Water
Temp, Min Boiler Temp and Central Heat Setpoint and Boost Time parameters.
0°F
(-18°C)
-40°F to 100°F
(-40°C to 37.8°C)
Central Heat Low Outdoor Temperature
The Low Outdoor Temperature parameter is also called “Outdoor Design
Temperature”. This parameter is the outdoor temperature used in the heat
loss calculation. It is typically set to the coldest outdoor temperature.
70°F
(21.1°C)
32°F to 100°F
(0°C to 37.8°C)
Central Heat High Outdoor Temperature
The High Outdoor Temperature parameter is the outdoor tempera-
ture at which the Low Boiler Water Temperature is supplied. This pa-
rameter is typically set to the desired building temperature.
110°F
(43.3°C)
70°F to 190°F
(21.1°C to 87.8°C)
Central Heat Low Boiler Water Temperature
The Low Boiler Water Temperature parameter is the operating setpoint when the
High Outdoor Temperature is measured. If the home feels cool during warm outdoor
conditions, the Low Boiler Water Temperature parameter should be increased.
130°F
(54.4°C)
80°F to 190°F
(26.7°C to 87.8°C)
Minimum Boiler Temperature (Central Heat and Auxiliary Heat)
The Minimum Boiler Temperature parameter sets a low limit for the Reset
setpoint. Set this parameter to the lowest supply water temperature that
will provide enough heat for the type radiation used to function properly.
Always consider the type of radiation when adjusting this parameter.
0 Minutes
0-1800 Seconds
(0-30 Minutes)
Central Heat Boost Time
When the Central Heat Setpoint is decreased by Outdoor Reset settings, the
Boost Time parameter is used to increase the operating setpoint when the home
heat demand is not satised after the Boost Time setting is exceeded. When heat
demand has been “on” continuously for longer than the Boost Time parameter
the operating setpoint is increased by 10°F (5.6°C). The highest operating
setpoint from Boost Time is current Central Heat Setpoint minus the Central
Heat “Diff Above” setting. A setting of 0 seconds disables this feature.