Lochinvar Knight Heating Boiler 81-286 - Manual (Page 22)

1
Service
Service Manual
LOW OUTDOOR
TEMPERATURE
(Default = 25°F)
HIGH OUTDOOR
TEMPERATURE
(Default = 70°F)
SET POINT AT
HIGH OUTDOOR
TEMPERATURE
(Default = 70°F)
SET POINT AT
LOW OUTDOOR
TEMPERATURE
(Default = 180°F)
(SH)
SET POINT
(Default = 125°F)
WATER
TEMPERATURE
SET POINT
OUTDOOR AIR
TEMPERATURE
Figure 1-1 Outdoor Air Reset Curve
Outdoor Reset
In accordance with the United States Energy Policy and
Conservation Act, this boiler is equipped with outdoor
reset, a feature that saves energy by reducing the boiler
water temperature as the heating load decreases. In the
absence of an external energy management system, outdoor
reset MUST BE used. To use this feature, the outdoor
sensor provided with the boiler must be properly installed.
For better zone control, three (3) individual outdoor reset
curves are available. If multiple zones are calling for heat,
the highest set point has priority. Each curve is created
using four (4) adjustable parameters: low outdoor air
temperature, high outdoor air temperature, set point at
low outdoor air temperature, and set point at high outdoor
air temperature. The set point is calculated using the
individual curve for each zone.
Outdoor (1 - 3) Low
This parameter specifies the low outdoor air temperature.
When the outdoor air temperature drops to this point, the
zone set point will be at the Set Point 1 at Low Outdoor
Temp 1, Set Point 2 at Low Outdoor Temp 2 and Set Point
3 at Low Outdoor Temp 3 parameters (FIG. 1-1). If the
outdoor air temperature drops further below this setting,
the set point will continue to increase. This parameter can
be changed by the installer by accessing the Outdoor (1-3)
Low parameters. The temperature range is -39°F (-39°C) to
high outdoor air temperature set point. The default value
is 25°F (-4°C).
Outdoor (1 - 3) High
This parameter specifies the high outdoor air temperature.
When the outdoor air temperature rises to or above this
point, the water temperature set point will be at Set point
(1 - 3) at High Outdoor Temp (1 - 3) parameters (FIG. 1-1).
This parameter can be changed by the installer by accessing
the Outdoor (1-3) High parameters. The temperature range is
low outdoor air temperature set point to 104°F (40°C). The
default value is 70°F (21°C).
Set Point (1 - 3) at Low Outdoor Temperature
When the outdoor air temperature drops to the Outdoor (1
- 3) Low parameter, the set point will be at this setting (FIG.
1-1). However, the outdoor reset curve is limited by the SH
(1 - 3) Set Points. If SH1, SH2, and SH3 are set lower, the
water temperature will be at these set points instead. If the
outdoor air temperature continues to drop below the Outdoor
(1 - 3) Low parameter, the set point will continue to increase
above this setting until SH1 (1 - 3) Set Point is met. These
parameters can be changed by the installer by accessing the
Set point 1 at Low Outdoor Temp 1, Set point 2 at Low Outdoor
Temp 2 and Set point 3 at Low Outdoor Temp 3 parameters.
The temperature range of this parameter is 68°F (20°C) to
180°F (82°C). The default value is 180°C (82°C).
Set Point (1 - 3) at High Outdoor Temperature
When the outdoor air temperature rises to or above the
Outdoor (1 - 3) High parameter, the calculated set point will
be at this setting (FIG. 1-1). These parameters can be changed
by the installer by accessing the Set point 1 at High Outdoor
Temp 1, Set point 2 at High Outdoor Temp 2 and Set point 3
at High Outdoor Temp 3 parameters. The temperature range
of this parameter is 68°F (20°C) to 190°F (88°C). The default
value is 70°F (21°C).
Outdoor Air Shutdown (SH1 - SH3)
The Outdoor Air Shutdown parameter specifies the outdoor
air temperature at which there is no longer space heating
demand. When the outdoor temperature rises above this
point, the control will block all SH demands (DHW demands
will still be active). These parameters can be changed by the
installer by accessing the Outdoor Air Shutdown SH1, SH2, and
SH3 parameters. The temperature range of this parameter is
32°F (0
°C) to 104°F (40°C). The default value is 70°F (21°C).
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