(Mar, 2012)
Compact CWE Series Installation, Operation & Maintenance Manual
Air Technology Systems, Inc.
1.5.1 Electric Box Access
The electrical components are protected behind the
hinged front access door on the front of the cabinet.
The access door is safety interlocked with the main
power service disconnect switch, preventing the door
from opening when the switch is in the “On” position.
The switch must be turned “Off” to gain access to the
electrical components.
The service disconnect switch may be used to turn
the unit off for emergency shutdown or
during routine
maintenance. The handle of the switch may be locked
in the “Off” position to prevent unintended operation
.
1.5.2 Circuit Breakers / Motor Start
Protectors
Individual overload protection is provided by circuit
breaker(s) and motor start protectors. These switches
must be manually reset once the overload condition
is cleared.
1.5.3 Heaters (Optional)
The precision A/C unit incorporates heaters for
re-heating the supply air as required to offset
the sensible cooling of the system during the
dehumidifi cation cycle and for the automatic heating
mode. As a standard, electric resistance heating
elements are factory installed in the supply airstream
to heat the supply air.
As an option, hot water reheat may be selected.
For this option a hot water heating coil is installed
in the supply air stream to heat the supply air. A
modulating valve is provided to control the fl ow of hot
water through the coil to maintain the correct reheat
temperature.
1.5.4 Coil(s)
The cooling and optional hot water reheating coils are
aluminum fi nned/copper tube construction. The coils
are leak tested and cleaned before installation by the
factory.
1.5.5 EC Fan(s)
The unit is equipped with high effi ciency,
Electronically Commutated (EC) fan(s). EC Fans
utilize a brushless motor equipped with permanent
magnets and permanently lubricated ball bearing.
The Fan impellers are backward curved and
attached to the rotor casing. The fan is balanced and
aerodynamically optimized to minimize vibration.
The fan does not utilize drive belts. The fan speed
is variable via a 0 to 10 VDC signal from the system
controller. The fan motor is equipped with integral
electronics and does not require the addition of
secondary electronics such as thermal protection,
inverters or fi lters. The fan will not produce AC inverter
whine.
EC fans feature an integrated monitoring function to
protect the motor and electronics against damage
from jamming, phase loss or overheating. If any
of the following failure conditions occur, the motor
automatically stops and an alarm is signaled:
a. Locked rotor
(1)
b. Low main supply voltage
(1)
c. Loss of a phase
(1)
d. Over-heating of electronics
(2)
e. Over-heating of motor
(2)
(1)
Upon correction of these failure conditions, the
motor will automatically reset.
(2)
Upon correction of these failure conditions, the
motor must be manually reset by turning off power
for 20 seconds.
1.5.6 Temperature/Humidity Sensor
As a standard, a temperature/humidity (T/H) sensor
is factory mounted in the return air stream for room
air control. The T/H sensor monitors the return
air conditions and provides input signal(s) to the
system controller to manage the operation of the
A/C unit consistent with the set points entered in the
controller. As an option, sensor(s) may be shipped
loose for fi eld installation. Refer to the electrical
drawing supplied with your unit for details specifi c to
your system. See Section 2.6.6.1 for descriptions of
the types of T/H control methods that may be utilized.
1.6 Optional
Equipment
1.6.1 Humidifi er
Compact CWE systems may utilize an optional
electrode steam humidifi er. For this option a
humidifi er is installed inside the air conditioner with
automatic fi ll and drain valves and associated piping.
Operation of the humidifi er’s fi ll and drain cycles is
based on water conductivity and is maintained by
the humidifi er controller. An operating manual for the
humidifi er is provided under separate cover. Refer to
that manual for detailed information on the operation
and maintenance of the humidifi er.
1.6.2 Condensate Pump
An optional condensate pump may be factory installed.
The pump automatically eliminates condensate and
humidifi er fl ush water (if applicable) from the drain
pan. An internal overfl ow safety switch is wired to
the system controller to automatically shut down the
precision A/C system should an overfl ow occur.
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