LAARS NeoTherm LC NTV1700 - Install and Operating Manual - Manual (Page 81)

NeoTherm LC Boilers and Water Heaters Page 77
4. Select Date and Time. Figure 107 shows the
setup screen.
Fig. 110 – Date and Time
9.5 Setup for Domestic Hot Water on
a Lead/Lag System
There are three ways that a NeoTherm LC system
can be set up to provide domestic hot water. Two
of them involve the use of an indirect water heater.
In a system including an indirect water heater, hot
water is circulated through a piping loop which
runs through an insulated water tank. Heat from
the water in the loop is transferred to the water in
the tank, and the heated water in the tank is used as
domestic hot water.
Setup Type 1 –
All of the boilers in the system can be set up to react
together if there is a call for domestic hot water.
This arrangement can be used for NTH or NTV
units. When NTH units are used in this kind of
setup, the demand for domestic hot water (DHW) is
given priority over the demand for central heat (CH).
If the system is producing heat for a CH demand,
and a call for DHW arrives, all of the boilers will
stop producing heat for CH, and the whole system
will respond to the DHW demand. The DHW pump
will start circulating water through the loop in the
indirect water heater. The System sensor is used to
control modulation in this configuration, so sensor
placement is critical.
This arrangement can be cumbersome if the demand
for domestic hot water is a lot less than the demand
for central heating. This can result in multiple
boilers “idling” as they wait for the DHW demand to
be satisfied.
Caution
For NTH units - This arrangement can only be
used in applications where all of the components
in the system are rated for both the maximum
hydronic temperature and the maximum DHW outlet
temperature.
The setup for this is all done from within the Lead/
Lag system. You will need to set up an LL CH
setpoint and a separate LL DHW setpoint, and assign
the priority to the DHW demand.
The input from the aquastat is brought to terminals
5 and 6 on TB6 on the controller which is acting as
the Lead/Lag Master. (Usually, this is the Primary
controller on Boiler 1.)
1. From the ‘home’ screen (Fig. 111), press the
View Lead Lag button.
Fig. 111 – ‘home’ screen
2. Press the button for Lead Lag Master. Fig.
112 shows the screen that follows.
Fig. 112 – Lead/Lag Master Screen
3. Press the Configure button. The display will
present the Lead/Lag Master Configuration
Screen (Fig. 113).