94 Operating the Water Heater
2-Stage T/S Output Heat-Capacity
Models with the 2-stage air handler control function
(W1, W2) can use a 2-stage thermostat or can be
automatically controlled by the H
2
Air controller (If
the H
2
Air DIP switch # 3 is OFF).
When using the automatic 2-stage heating feature,
the system will modulate between the 1-stage and
2-stage based on the set heat capacity parameter
of the water heater. This heat capacity value can be
adjusted based on the desired modulation point
(default heat capacity is 25%)
Note
The following parameter is used for the
2-stage T/S output heat-capacity:
●
P.07: AHU 2Stage T/S Output
6.5.2 Configuring a Cascade System
1. Press and hold the Menu button ( ) and the Back
button ( ) simultaneously for 3 seconds and then
select
2. Cascade Status and Set
.
2. Press the Up button ( ) or the Down button
( ) to switch between the parameters or to
increase or decrease setting values. Press the OK
button ( ) to select a parameter or to confirm
after making changes.
Outdoor Reset Control
The Outdoor Reset Control feature can be used
to enhance energy efficiency while maintaining
optimal heating performance. Outdoor Reset
Control automatically changes the space heating
temperature setting based on the outdoor
temperature and the current space heating system
application (system load).
To achieve optimal heating performance,
configure the following set-points: the Outdoor
Low Temperature, the Outdoor High Temperature,
the heating MIN and the heating MAX Set-point
configuration must be based on the H
2
Air system
characteristics and installation environment.
Refer to the following examples in the graph to
configure the Outdoor Reset Control feature.
Outdoor Reset Curve
Parameter_Default
Parameter_Setting1
Parameter_Setting2
Outdoor Temperature
Setting
Temper
atur
e
* The graph above is an example of a few possible outdoor
reset parameter settings. For more information about
settings, refer to the following information.
* If the Outdoor Reset On (H
2
Air DIP switch #1 OFF) is set
and the outdoor temperature sensor is not connected,
or the outdoor temperature sensor value is outside the
normal range, the ‘740’ error message is displayed and
the system operates the same way as with the Outdoor
Reset OFF (H
2
Air DIP switch #1 ON) setting.
Note
The following parameters are used for
the outdoor reset control:
●
P.03: AHU Outdoor Low Temp
●
P.04: AHU Outdoor High Temp
●
P.05: AHU SH MIN Set-point
●
P.06: AHU SH MAX Set-point
Summary of Contents for NPE-180A2
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