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Normally, the thermal expansion valve need not be ad-
justed in the field. If, however, adjustment needs to be
made, the expansion valve adjusting screw should be
turned not more than one turn at a time, allowing suffi-
cient time (approximately 15 minutes) between adjust-
ments for the system and the thermal expansion valve
to respond and settle out. Assure that superheat is set at
10 - 15°F (6 - 8°C).
q
2. Record the suction temperature, suction pres-
sure, suction pressure converted to temperature,
and superheat of each system below:
SYS 1 SYS 2
Suction Temp = ____
____
Suction Press = ____
____
Temp = ____
____
Superheat = ____
____
CHECKING ECONOMIZER SUPERHEAT
(IF APPLICABLE) (15 TON TXV)
The economizer superheat should be checked to assure
proper economizer operation and motor cooling. Cor-
rect superheat setting is approx. 10 - 12°F (6 - 7°C).
The superheat is calculated as the difference between
the pressure at the Economizer Service Valve on the
compressor converted to the corresponding tempera-
ture in a standard pressure/temperature chart and tem-
perature of the gas at the bulb on the entering piping to
the motor housing.
Example:
Motor Gas Temp =
minus Economizer Press
139 PSIG converted
to Temp
YORK INTERNATIONAL
SYS 3 SYS 4
____
____ PSIG (kPa)
____
____ °F
(0°C)
____
____ °F
(0°C)
____
____ °F
(0°C)
90°F (32°C)
- 78°F (26°C)
12°F (6°C)
Normally, the thermal expansion valve need not be ad-
justed in the field. If however, adjustment needs to be
made, the expansion valve adjusting screw should be
turned not more than one turn at a time, allowing suffi-
cient time (approximately 15 minutes) between adjust-
ments for the system and the thermal expansion valve
to respond and settle out. Assure that superheat is set
between 10 - 12°F (6 - 7°C).
q
1. Record the motor gas temperature, economizer
pressure, economizer pressure converted to tem-
perature, and economizer superheat below:
SYS 1 SYS 2
= ____
____
Motor Gas Temp
= ____
____
Economizer Press
= ____
____
Temp
= ____
____
Superheat
This superheat should only be checked
in an ambient above 90°F (32°C). Oth-
erwise, mid-range adjustment (factory
setting) is acceptable.
LEAK CHECKING
q
1. Leak check compressors, fittings, and piping to
assure no leaks.
If the unit is functioning satisfactorily during the initial
operating period, no safeties trip and the compressors
load and unload to control water temperature, the chiller
is ready to be placed into operation.
FORM 201.18-NM3
SYS 3 SYS 4
____
____ PSIG (kPa)
____
____ °F
(°C)
____
____ °F
(°C)
____
____ °F
(°C)
135
7
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