IM 742 / Page 5
Electrical Data
1 . Verify the compatibility between the voltage and phase
of the available power and that shown on the unit serial
plate . Line and low voltage wiring must comply with
local codes or the National Electrical Code, whichever
applies .
2 . Apply correct line voltage to the unit . A
7
⁄
8
" (22mm) hole
and/or a 1
1
⁄
8
" (29 mm) knockout is supplied on the side
of the unit . A disconnect switch near the unit is required
by code . Power to the unit must be sized correctly and
have dual element (Class RK5) fuses or an HACR circuit
General
breaker for branch circuit overcurrent protection . See the
nameplate for correct ratings .
3 . Three phase 50 cycle units, 380/50/3, require a neutral
wire for 230/50/1 power to the fan circuit .
4 . Connect the thermostat/subbase wiring with the power
“off ” to the unit .
5 .
Field supplied relays installed on the input terminals W1, W2, Y1,
Y2 or G may introduce electrical noise. Never install relay coils in
series with the inputs.
230 Volt Operation
Fan Assembly
All 208-230 volt single-phase and three-phase units are
factory wired for 208 volt operation . For 230 phase opera-
tion, the line voltage tap on the 24 volt transformer must be
All fan motors are multi-speed, PSC type with integral
mounting brackets and thermal overload protection . The
motor is isolated from the fan housing for minimum vibration
transmission . Fan motors on 019 thru 070 have a terminal
strip on the motor body for simple motor speed change
without going back to the control box . To change fan motor
speed to high on size 015 through 048, interchange the red
wire with the black wire . For low speed, sizes 012, 024,
030, 036, 042, 060 and 070, interchange the black wire with
the red wire . To change the 460 volt motor from high to low
speed, interchange Black and Red wires, then add jumper
between Black and Blue wires . All the fan/motor assemblies
have a removable orifice ring on the housing to accommo-
date motor and fan wheel removal without disconnecting the
ductwork . The fan housing protrudes through the cabinet
allowing adequate material for connection of flexible duct .
Each model unit is shipped from the factory for maximum
performance and minimum sound requirements . Fan sound
levels and performance can be affected by external static
pressure .
changed . Disconnect and cap the red lead wire and inter-
change it with the orange lead wire on the primary of the 24
volt transformer .
Piping
1 . All units should be connected to supply and return pip-
ing in a two-pipe reverse return configuration . A reverse
return system is inherently self-balancing and requires
only trim balancing where multiple quantities of units
with different flow and pressure drop characteristics
exist in the same loop . Check for proper water balance
by measuring differential temperature reading across
the water connections . To insure proper water flow, the
differential flow should be 10°F to 14°F (5°C to 8°C) for
units in cooling mode .
A direct return system may also work acceptably, but
proper water flow balancing is more difficult to achieve
and maintain .
2 . The piping can be steel, copper or PVC .
3 . Supply and return runouts usually join the unit via short
lengths of high pressure flexible hose which are sound
attenuators for both unit operating noise and hydraulic
pumping noise . One end of the hose should have a
swivel fitting to facilitate removal for service . Hard pip-
ing can also be brought directly to the unit . This option
is not recommended since no vibration or noise attenu-
ation can be accomplished . The hard piping must have
unions to facilitate unit removal . See Figure 5 for typical
piping setup .
4 . Some flexible hose threaded fittings are supplied with
sealant compound . If not, apply Teflon tape to assure a
tight seal .
5 . Supply and return shutoff valves are required at each
conditioner . The return valve is used for balancing and
should have a “memory stop” so that it can always be
closed off but can only be reopened to the proper posi-
tion for the flow required .
6 . No unit should be connected to the supply and return
piping until the water system has been cleaned and
flushed completely . After the cleaning and flushing
has taken place, the initial connection should have
all valves wide open in preparation for water system
flushing .
Figure 4. CCH, CCW, CRH & CRW Sizes 007 thru 070
(Factory wired)
Note: For low speed applications a jumper must be installed between the motor's Black and
Blue terminal.
Figure 4a. CCH, CCW, CRH & CRW Sizes 042 thru 070
(Factory wired, 460 volt motor only)