AHRI K2WT, Installation, Operating And Service Instructions

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“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
8. The maximum set point is defined 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 defined 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 temperature at which the Low
Boiler Water Temperature is supplied. This parameter 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.
20 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
satisfied 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. A setting of 0 seconds disables this feature. Boost is not used when Sequence
Master is enabled.
XII. Operation
F. Changing Adjustable Parameters (continued)