LAARS NeoTherm NTV (Sizes 150–850 MBTU/h) - Install and Operating Manual - Manual (Page 41)

Page 37 N eo T herm Boilers and Water heaters
Caution
The supply voltage to the NeoTherm unit must not
be disconnected, except for service or isolation, or
unless otherwise instructed by procedures outlined
in this manual. To signal a call for heat, use the 24V
field interlock, as shown in the wiring diagram.
DO NOT MAKE AND BREAK THE LINE VOLTAGE
TO THE NEOTHERM UNIT TO SIGNAL A CALL
FOR HEAT. A call for heat/ end call for heat MUST
be connected to the field interlock terminals. Some
NeoTherm components are designed to have
constant voltage during normal operation. If the
NeoTherm’s supply voltage is toggled as a call for
heat signal, premature failure of these components
may result.
The NeoTherm unit does not recognize 4mA as a
signal to shut off. If the call for heat is not connected
between the field interlock terminals, the NeoTherm
will remain in low fire when it sees 4mA as a
modulating signal.
8B.2 Main Power Connections
Connect a 15A fused, 120-volt supply to the main power
switch. (The hot leg is connected directly to the switch.)
The neutral leg is connected directly to the white wire. The
ground wire can be connected to the grounding lug on the
control panel. (See Fig. 34.)
8B.3 Pump Connections and Operation
The controller in the NeoTherm energizes the pump contacts
when it receives a call for heat. Once the call for heat is
satisfied, the pump will remain on for the defined pump
overrun time.
The Boiler Pump terminals (TB5 - max 7.4 FLA) are fed
by 120V (violet wire) internally from the main power feed.
The System and DHW contacts are dry contacts. Appropriate
voltage must be supplied to the System and DHW pumps for
proper operation.
The System pump connections are located on terminal block
5 (TB5) in the control panel. (See Figure 34.) The System
pump contacts are rated for 120Vac, 7.4 Amps. To use the
contacts, power must be supplied on one terminal with the
other terminal wired to the pump or a relay controlling the
pump.
The DHW pump connections are located on terminal block
5 (TB5) in the control panel and are rated for 120Vac, 7.4
Amps. To use the contacts, power must be supplied on one
terminal, and the other terminal wired to the pump or a relay
controlling the pump.
Additional 120VAC circuits may be required for the pumps.
Once the unit has been installed and set up, the Quick Start
menu provides a simple way to change the most common
settings used in a typical installation. (If your installation is
more complex, refer to Section 8C.) To reach the Quick Start
menu, press the “I” button (“Info/Install”), then press the
Quick Start menu item.
WATER HEATER
SIZES VOLTS PHASE AMPS
150-500 120 Single 2*
No pump
150-199
120 Single 7*
With pump
285-500
120 Single 8*
With pump
600-850
See Pump Rating Plate FLA
No pump (must be less than 7.4 FLA)
* Minimum 15A circuit required
Table 13 - NTV Electrical Data
BOILER PUMP CONNECTIONS
RATINGS
SIZES VOLTS PHASE AMPS (Boiler, System Pump and
DHW Pump Connections)
80–850 120 Single 2 * 115V – Maximum 1HP
No Pump or 7.4A max
80-500 Less
With Pump 120 Single than
115V – Maximum 1HP
6 *
or 7.4A max
* Minimum 15A circuit required
Table 12 - NTH Electrical Data