Water Connections; Electrical Connections; Motorized Valve And Control - Carrier 42 GW serie Installationsanweisung

Water connections

Water connections are fixed to the unit body to avoid damage
when pipes are connected; it is advisable to tighten the
connection with a spanner.
The upper coil connection is supplied with an air purge valve,
the lower connection with a water purge valve, suitable for a
10 mm wrench or screw-driver (See fig. 26).
(The coil is only partially drainable; it it is advisable to
blow air into the coil for complete drainage).
Models Connections
dimension (Ø)
004 3/4"
008 3/4"
010 3/4"
004 1/2"
*
008 1/2"
*
010 1/2"
*

Electrical connections

We recommend to remove the main board from the electric panelboard
for better access to electric connections.
STANDARD version unit -
Control panel (See fig. 35)
The control panel can be reached by opening the grille and
removing the metal covers using the 3 or 4 screws (See fig. 36)
IMPORTANT for units with electric heaters;
The unit is equipped with two thermostats: one with automatic reset
and one with manual (electric) reset that can be reactivated by
switching the power supply off and then on.
Connect the power cables to terminal box connectors in accordance
with the wiring diagram and tighten firmly (See fig. 38-39-40).
IMPORTANT: Make ground connection prior to any other
electrical connections.

Motorized valve and control

• The unit control circuit only allows opening of the motorized
valve when the fan motor is working
(See wiring diagrams fig. 42)
• When the thermostat asks for cooling, terminal 1 of TB3 (cold
water) is supplied with 230V.
When it asks for heating, terminal 2 of TB3 (hot water or
electric heater) is supplied with 230V.
• The control circuit ensures that the condensate discharge
pump works continuously while the thermostat, asking for
cooling, keeps the cold water regulating valve open.
WARNING :
The valve is not only necessary to control the room tempe-
rature, but also to stop the cold water flow to the coil in
case of an abnormal condensing water level rise in the drain
pan.
Models Connections
dimension (Ø)
012 1"
016 1"
020 1"
020 3/4"
*
* Hot water circuits, four-pipe version
It is necessary, when the installation is made, to insulate the
valve and the connection pipes with anti-condensate material
of polyethylene type or expanded neoprene.
Checking
Before unit operation pour a quantity of water into the external
auxiliary drain pan (See fig. 27). Verify that the water flows into
the internal condensate drain pan and that the pump regularly
drains the liquid.
Otherwise check the pipe slope and look for possible
obstructions. Water connections are fixed to the unit body to
avoid damage when pipes are connected; it is advisable to
tighten the connection with a spanner.
• If the unit is fitted with an electric heater, this must have a separa-
te power supply.
According to the installation instructions, all devices for
disconnection from the power supply mains must have a contact
opening (4 mm) to allow total disconnection according to the
conditions provided for the overvoltage class III.
• Fix the power cable of the electric resistance heaters under the
single cable clamp. Make certain that the YELLOW/GREEN cable
is stripped back further than the others (See fig. 37-43).
Unit with electric heaters
To connect the electric heaters to power supply see fig. 41.
IMPORTANT for units with electric heaters;
The unit is equipped with two thermostats: one with automatic reset
and one with manual (electric) reset that can be reactivated by
switching the power supply off and then on.
• If there is an abnormal condensing water rise in the drain pan
(for example: possible defective drain, pump malfunction, fan
motor not working) causing the opening of the float switch
contact (FS), the control circuit either operates the c
ondensate drain pump, or at the same time closes the
regulating valve, stopping the cold water flow towards the coil
and avoiding further condensation.
Control
The water flow has to be controlled:
• by installing the motorized thermo-electric valves supplied
as accessory
or
• by installing motorized field supplied valves.
42 GW 25