LAARS NeoTherm LC NTV1700 - Install and Operating Manual - Manual (Page 69)

NeoTherm LC Boilers and Water Heaters Page 65
DHW time of day setpoint -
Separate Time-of-Day Setpoint for Domestic
Hot Water (See the material on “About the
‘Time of Day’ Function at the end of this
section)
Modbus port -
Always use MB1
4. To see the other settings related to the Lead/
Lag functions, press the button for Advanced
Settings. This leads to a “ring” of related
screens, and you can scroll through the list
by pressing one of the left- or right-arrow
symbols. The screens in this ring are:
Modulation
Central Heat
Domestic Hot Water
Frost Proection
Outdoor Reset
Warm Weather Shutdown
Algorithms
Rate Allocation
Add Stage
Drop Stage
5. Press the left-arrow or right-arrow until you
see the Modulation screen (Fig. 83).
Fig. 83 – Modulation
Three of the items on this screen can be
changed:
Off hysteresis -
The system will not shut off the burners
until the System sensor reaches the CH
Setpoint plus an additional “hysteresis”
value.
On hysteresis -
The system will not fire the burners until
the System sensor reaches the LL CH
Setpoint minus an additional “hysteresis”
value.
P, I, D Gain -
These control the “damping” used by the
temperature control. The three control
values are P (proportional), I (integral)
and D (derivative). If you understand how
these variables affect the function of the
unit, you can change them to adjust for
unusual operating conditions. The default
settings for the Lead/Lag configuration are:
P = 30, I = 20, and D = 0.
6. Press the left-arrow or right-arrow until you
see the Central Heat screen (Fig. 84).
Fig. 84 – Central Heat
Setpoint source -
This sets the source of the System sensor
input used to control the system. The
options here are Local and 4-20 mA.
(For instructions on setting up for a 4-20
mA input, see Job #5 in the section on
“Installation Options.”)
Setpoint -
This is the same as the LL CH Setpoint on
the Lead/Lag Master Configuration screen
(Fig. 82).
Time of day setpoint -
This is the same as the LL CH Time-Of-
Day Setpoint on the Lead/Lag Master
Configuration screen (Fig. 82). (See the
material on “About the ‘Time of Day’
Function at the end of this section)
4 mA water temperature -
If a 4 – 20 mA input is used to adjust the
setpoint, this entry sets the low limit of the
control range. (In the example shown here,
an input of 4 mA would result in a setpoint
of 90°F.)