LAARS Heating Systems
Page 36
WARNING
Electrical Shock Hazard
Electrical shock can cause severe injury, death or
property damage. Disconnect the power supply
before beginning installation or changing the
wiring to prevent electrical shock or damage to the
equipment. It may be necessary to turn off more
than one power supply disconnect.
All electrical wiring is to be done in accordance with
local codes, or in the absence of local codes, with:
1) The National Electrical Code ANSI/NFPA No. 70
- latest Edition, or
2) CSA STD. C22.1 “Canadian Electrical Code -
Part 1.” This unit must be electrically grounded in
accordance with these codes.
NOTE: When running the Power and Field
Connection wirings between the units (Lead
Lag, System Sensor, Outdoor Sensor, Building
Automation, etc.), it is helpful to exit and enter the
units through the lower back panels so that during
future servicing, the wires are not in the way and
do not have to be disconnected in order to remove
the top and side panels.
AVIS: Lors de l’exécution du domaine d’alimentation
et les fils électriques de connexion entre les unités
(Lead Lag, Capteur, système capteur extérieur,
domotique, etc.), il est utile pour sortir et entrer les
unités à travers la partie inférieure arrière de sorte
qu’au cours de l’entretien futur, les fils ne sont pas
dans la voie et n’ont pas à être déconnecté afin
d’enlever le haut et le côté.
available at terminal 22. Contact ratings are 250VAC,
1.5A maximum. DHW pump functionality is configured
using the touch screen.
System Pump - if connecting a system pump, use
terminals 23 and 24. As this is a dry contact, the system
pump supply voltage or system pump relay coil voltage
would be applied at terminal 23, and when the system
pump is activated, would be available at terminal 24.
Contact ratings are 250VAC, 1.5A maximum. System
pump functionality is configured using the touch screen.
Auxiliary – no functionality is available on this unit.
Alarm Bell – if connecting an alarm bell, use terminals
27 and 28. As this is a dry contact, the alarm bell supply
voltage is applied at terminal 27, with the alarm bell
connected to terminal 28.
7.D.3 Temperature Sensors
System Supply - if used, is connected to terminals
29 and 30 (See Figure 19 on page 35). When
connected, the controller automatically detects the
presence of this sensor and the temperature is shown
on the home screen above the red system supply
arrow. When installed, the unit controls the firing rate
to maintain the system supply temperature to the heat
demand set point.
System Return - if used, is connected to terminals 31
and 32. When connected, the controller automatically
detects the presence of this sensor and the temperature
is shown on the home screen above the blue system
output arrow. There is no control logic associated with
this sensor.
Domestic Hot Water (DHW) - if used, is connected to
terminals 33 and 34. When connected, the unit will use
this sensor to perform the DHW thermostat function and
the temperature is shown on the home screen below
the faucet icon. The controller automatically detects the
presence of this sensor and initiates a call for heat when
the DHW temperature drops below the DHW set point
by the value of the DHW On Hysteresis (DHW Set Point
– DHW On Hysteresis = DHW heat demand).
Outdoor - if used, is connected to terminals 35 and 36.
When connected, the controller automatically detects
the presence of this sensor and the temperature is
shown on the home screen as the Outdoor Ambient
Temperature (OAT). If installed, options such as
outdoor reset and warm weather shutdown can be
enabled through the display. Always install the Outdoor
Sensor at an outdoor location that is not affected by
false temperature readings such as sunlight or hot
equipment.
7.D.4 Heat Demands
TT1 - if a thermostat/aquastat or end switch (isolated
contact only) is used as a heat demand, connect to
terminals 37 and 38 (See Figure 19 on page 35).
TT1 functionality is configured on the touch screen on
the CH1/DHW1 screens.
Figure 20. Hinged Control Panel
Hinged control
panel swings
open for easy
servicing and
setup
