York CH012, Installation Instructions Manual

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036-33073-001 Rev. A (0701)
4 Unitary Products Group
ELECTRICAL POWER SUPPLY AND
CONNECTIONS
Before installing the unit, make sure that the voltage and
number of phases on the unit data plate are the same as the
available power supply. A fused disconnect or circuit breaker
must be provided within the sight of anyone working on the
unit. The size of fuses or circuit breaker required is shown on
the unit data label. Fuses must be of the time delay type. The
power supply wiring is to be connected directly to the line
side of compressor contactor as shown on the connection
wiring diagram. A ground wire must be connected to the
ground lug marked GND in the electrical control box. A 7/8-
inch diameter hole is provided in the unit corner post for the
entry of the power wiring.
ROOM THERMOSTAT AND CONTROL
WIRING
Any cooling only 24-volt room thermostat can be used with
these units. It is recommended that the thermostat sub-base
should include a fan switch, so that constant fan operation
can be selected if desired. Three control wires are required
from the unit to the thermostat. It is preferred that the wires
be colored red, yellow, and green. Using these colors simpli-
fies connecting the red, yellow, and green terminals on the
thermostat to the red, yellow, and green terminals on the unit
low voltage terminal strip. Room thermostats can be ordered
as an optional accessory for delivery with the units if desired.
BLOWER PERFORMANCE
All units have blower motors that have three speeds avail-
able, except the 460 and 575-volt units. The motors have
been selected to deliver the nominal air volume against high
external static pressures when necessary. Therefore, it will be
necessary to check the air volume obtained on every installa-
tion and change the motor speed connection accordingly, if
the air volume is too high or too low. The units are factory-
wired with the medium speed winding connected.
Three methods are available to measure the air volume. The
preferred method is to measure the actual cubic feet per
minute of air being circulated, if suitable instruments for doing
this are available. Then if necessary, change the motor speed
to try to get the nominal air volume of 400 CFM per ton of
cooling capacity, within plus or minus 10 percent.
The second method is to measure the difference between the
supply and return air temperatures. The temperature differ-
ence should be in the range of 18°F to 25°F. If it is not, reduce
the motor speed if it is less than 18°F, and increase the motor
speed if it is more than 25°F .
The third method is to measure the external static pressure
obtained, and use the fan perfom1ance table for the unit. The
following performance tables are 230-volt operation. Slightly
lower air volumes will be obtained on 208-volt operation.
1. At higher evaporator air flows and wet bulb conditions,
condensate carry-over may occur. Adjust airflow down-
ward as necessary.
2. Values include pressure drop from wet coil and clean fil-
ters.
CONDENSER WATER SUPPLY AND
CONNECTIONS
The cooling water for the condenser may be from the mains,
a cooling tower, or a chilled water system. An automatic
water flow regulating valve is normally required, except if the
inlet water temperature is constant and the flow rate can be
pre-set and turned on and off by some other means, such as
a pump or solenoid valve.
Automatic water flow regulating valves are available as
accessories in either 3/8, 1/2, or 3/4-inch sizes and for maxi-
mum water pressure ratings of 150 PSI or 350 PSI. The fol-
lowing table shows the recommended valve size for each unit
model depending on the temperature of the water supply
available.
TABLE 2: EVAPORATOR BLOWER PERFORMANCE (CFM)
Unit
Model
Blower
Speed External Static Pressure (in w.g.)
0.1 0.2 0.3 0.4 0.5 0.6 0.7
060 High 2200 2120 2040 1980 1880 1780 1660
Med. 2060 2020 1940 1880 1800 1700 1600
Low 1800 1780 1740 1680 1620 1560 -
048 High 1900 1840 1780 1720 1620 1540 1440
Med. 1720 1680 1640 1580 1520 1420 1320
Low - 1405 1400 1380 1340 - -
036 High 1420 1370 1310 1250 1180 1110 1020
Med. 1300 1260 1220 1170 1110 1040 960
Low - 1120 1110 1070 1030 960 -
030 High 1240 1190 1130 1080 1010 930 850
Med. 1050 1030 1000 960 910 840 750
Low - 9 25 910 880 830 770 -
024 High 1070 1020 970 920 850 770 690
Med. 930 910 880 840 780 710 630
Low 810 805 800 770 730 670 -
018 High 770 730 695 645 590 525 -
Med. 690 660 625 585 5 3 0 - -
Low 520 500 495 - - - -
012 High 480 455 425 400 365 325 -
Med. 425 410 380 350 315 - -
Low 350 335 315 - - - -