Quantech QTC40160, Installation Operation & Maintenance

Page: 37 / 188

Section 4 - Installation
Quantech
37
Form QTC4-NM2
Issue date: 05/12/2023
4
After power wiring connection, do not
switch on mains power to the unit. Some
internal components are live when the
mains are switched on and this must only
be done by authorized persons familiar
with starting, operating, and trouble-
shooting this type of equipment.
Power wiring
All electrical wiring must be carried out in accordance
with local regulations. Route properly sized cables to
cable entries on the unit.
In accordance with local codes, NEC codes, UL and
CE standards, it is the responsibility of the user to
install over current protection devices between the
supply conductors and the power supply terminals on
the unit.
To ensure that no eddy currents are set up in the power
panel, the cables forming the 3-phase power supply
must enter using the same cable entry.
All sources of supply to the unit must be
taken using a common point of isolation
(not supplied by Quantech).
Copper power wiring only must be used for supply-
ing power to the chiller. This is recommended to avoid
safety and reliability issues resulting from connection
failure at the power connections to the chiller. Alumi-
num wiring is not recommended due to thermal char-
acteristics that may cause loose terminations result-
ing from the contraction and expansion of the wiring.
Aluminum oxide may also build up at the termination
causing hot spots and eventual failure. If aluminum
wiring is used to supply power to the chiller, Use AL-
CU compression fittings to transition from aluminum
to copper, using an external box separate to the power
panel. Then you can run copper conductors from the
box to the chiller.
Caulk power and control wiring conduit
entering the power panel to ensure moist
air from the building cannot enter the
panel.
Power supply wiring
• Units require only one 3-phase supply, plus earth.
• Connect the 3-phase supplies to the circuit breaker
located in the panel See Table 4 on page 45 .
• Connect a suitably sized earth wire to the PE ter-
minal in the panel.
115 VAC control supply transformer
A three-wire high voltage to 115 VAC supply trans-
former is standard in the chiller. This transformer is
mounted in the cabinet and steps down the high voltage
supply to 115 VAC to be used by the controls, VSD,
feed and drain valve controller, valves, solenoids, heat-
ers, and other relevant components.
The high voltage for the transformer primary is taken
from the chiller input. Fusing is provided for the trans-
former.
Removing high voltage power to the
chiller will remove the 115 VAC supply
voltage to the control panel circuitry
and the evaporator heater mat. In sub-
freezing weather, this could cause serious
damage to the chiller due to evaporator
freeze-up. Do not remove power unless
alternate means are taken to ensure op-
eration of the control panel, evaporator
heater mat, and waterbox heaters.
Control wiring
All control wiring that uses contact closures to the
control panel terminal block is nominal 115 VAC and
must be run in shielded cable, with the shield grounded
at the panel end only, and run in watertight conduit.
Run shielded cable separately from mains cable to
avoid electrical noise pick-up. Use the control panel
cable entry to avoid the power cables.
Voltage free contacts connected to the panel must be
suitable for 115 VAC 10 mA (gold contacts recommend-
ed). If the voltage free contacts form part of a relay or
contactor, the coil of the device must be suppressed using
a standard R/C suppressor. The above precautions must
be taken to avoid electrical noise, which could cause a
malfunction or damage to the unit and its controls.