OPTIONAL FEATURES
HeatNet Control V3 2.x
Outdoor Reset
The Outdoor reset feature allows the water setpoint
temperature to change dynamically with the outside air
temperature. It also provides an adjustable temperature that
shuts the boiler (or boiler system) down when the outside
temperature rises above it.
Figure 25
Outdoor reset curve, typical
The above chart shows how the water temperature setpoint
changes with the Outside air temperature. The four values of
180, 10 and 140, 70 are the default values:
WATER TEMP
LOW OA TEMP
180 °F
10 °F
Water temp @
outside air temp
WATER TEMP
HIGH OA TEMP
140 °F
70 °F
Water temp @
outside air temp
WWS Setpoint
72 °F
Outside air temperature
where Warm Weather
Shutdown occurs
WARM WEATHER SD=ON
If set to ON here
The chart depicts what the water temperature setpoint will
equal with a corresponding outside air temperature. At an
outside temperature of 10F and below, the water temperature
setpoint will be limited to 180F. With an outdoor temperature
of 70F and above, the water temperature will be limited to
140F. The water temperature setpoint will track along the
charts plotted line with corresponding outside temperatures.
The OR OVR (Outdoor Reset Override) input on J12A can be
used to override this Outside Air Setpoint and maintain the
water setpoint at the LOCAL or SYSTEM SETPOINT value
when a contact is closed across this input. This can be used as
a Domestic Hot Water demand input.
Another function of the OUTDOOR RESET is the
Winter/Summer mode ( (W)arm (W)eather (S)hutdown).
With the WWS SETPOINT set to 72F and WARM
WEATHER SHUTDOWN set to ON, the boiler/system will
enter summer shutdown when the Outside Air temperature
rises above 72F. While in this state, the OR OVR input on
J12A can be used to bring the boiler/system on to maintain
the water setpoint at the LOCAL or SYSTEM SETPOINT
value.
During WWS operation, the System pump will not be enabled
just the Local pump unless the SETTINGS:SYSTEM
PUMP:OVERRIDE ENABLED IN WARM WEATHER
SHUTDOWN is set to ON. This is the System Pump
Priority mode. When SETTINGS:SYSTEM PUMP:
OVERRIDE ENABLED IN WARM WEATHER
SHUTDOWN is set to OFF, the system pump will not come
on while in WWS with the OR OVR override input closed.
Sensors
The H-Net control supports a standard 10K thermistor (Type
ACI/10K-CP). These sensors can be calibrated to the control
by entering the sensor menu and placing a precision 10k
resistor on an input.
Immersion sensors must have wells.
There is also a provision to use a 1K platinum sensor for the
stack temperature. The 10k thermistor is limited to a usable
range of 270F, and the 1k platinum sensor to upwards of
1000F. The S5 DIP switch is used to configure one or the
other.
Stack Temperature
The version 3 control also supports an optional 1k platinum
stack sensor. If the Stack Sensor is present, a warning will
occur at 325F and greater. During the Warning condition, for
every degree F over the warning temperature of 325F, the
boiler‟s input will be limited by 4% until the boiler is running
at low fire. If the SETTINGS: HEAT EXCHANGER:
130
140
150
160
170
180
190
10
70
Wate
r Te
m
p
Outside Temp
WATER TEMPERATURE SETPOINT
33
Summary of Contents for KN-10
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