York YCAS0098EB, Установка, эксплуатация и обслуживание, Страница: 121 / 184

121
JOHNSON CONTROLS
FORM 201.18-NM7
CHECKING ECONOMIZER SUPERHEAT
(IF APPLICABLE) (15 TON TXV)
The economizer superheat should be checked to assure
proper economizer operation and motor cooling. Correct
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 temperature
in a standard pressure/temperature chart and tempera-
ture of the gas at the bulb on the entering piping to the
motor housing.
Example:
Motor Gas Temp = 90°F (32°C)
minus Economizer Press
139 PSIG converted
to Temp - 78°F (26°C)
12°F (6°C)
Normally, the thermal expansion valve need not be
adjusted 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
sufficient time (approximately 15 minutes) between
adjustments 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).

2. Record the suction temperature, suction pressure,
suction pressure converted to temperature, and
superheat of each system below:
Normally, the thermal expansion valve need not be
adjusted 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
sufficient time (approximately 15 minutes) between
adjustments 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).

1. Record the motor gas temperature, economizer
pressure, economizer pressure converted to
temperature, and economizer superheat below:
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

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.
SYS 1 SYS 2
Suction Temp = PSIG (kPa)
Suction Temp = °F (°C)
Temp = °F (°C)
Superheat = °F (°C)
SYS 1 SYS 2
Motor Gas Temp = PSIG (kPa)
Economizer Press
= °F (°C)
Temp = °F (°C)
Superheat = °F (°C)
7