97JOHNSON CONTROLS
FORM NO.: 6U6K-B01E-NB-EN
D. CHECKING SUPERHEAT AND SUBCOOLING
Example:
Liquid line pressure =
2700kPa converted to temp. 46 °C
Minus liquid line temp. - 40 °C
Subcooling = 6 °C
The subcooling should be adjusted to 6~9 °C
at design conditions.
SYS 1 SYS 2
Liq. Line Press = ––––––– ––––––– kPa
Saturated Temp = ––––––– ––––––– °C
Liq. Line Temp = ––––––– ––––––– °C
Subcooling = ––––––– ––––––– °C
Example:
Suction Temp = 10 °C
Minus Suction Pressure
800kPa converted to Temp 4 °C
Superheat = 6 °C
Assure that superheat is set at a minimum of 5
°
C with a single compressor running on each
circuit.
SYS 1 SYS 2
Suction Temp = ––––––– ––––––– kPa
Suction Pressure = ––––––– ––––––– °C
Saturation Temp = ––––––– ––––––– °C
Superheat = ––––––– ––––––– °C
E. LEAK CHECKING
Leak check compressors, fittings, and piping to
ensure no leaks. ...........................................
□
If the unit is functioning satisfactorily during the
initial operating period, no safeties trip and the
compressors cycle to control water temperature
to setpoint, the unit is ready to be placed into
operation.
The subcooling temperature of each system can
be calculated by recording the temperature of
the liquid line at the outlet of the condenser and
subtracting it from the liquid line saturation
temperature (liquid line saturation temp. is
converted from a temperature/pressure chart).
1.Record the liquid line pressure and its
corresponding temperature, liquid line tempera-
ture and subcooling below: ............................
□
After the subcooling is verified, the suction
superheat should be checked. The superheat
should be checked only after steady state opera-
tion of the unit has been established, the leaving
water temperature, and the unit is running in a
fully loaded condition. Correct superheat setting
for a system is 5 °C - 9 °C) in cooling mode.
Superheat should typically be set for not less than 5 °C
in cooling mode and 3 °C in heating mode. The
superheat is calculated as the difference
between the actual temperature of the returned
refrigerant gas in the suction line entering the
compressor and the temperature corresponding
to the suction pressure as shown in a standard
pressure/temperature chart.
2. Record the suction temperature, suction press-
ure, suction saturation temperature, and super-
heat of each system below:
YORK Guangzhou Air Conditioning & Refrigeration Co., Ltd
Copyright © by Johnson Controls 2017
800-861-1001
www.johnsoncontrols.com
Subject to change without notice. Printed in China
ALL RIGHTS RESERVED
Issue Date: September 20, 2017
Printed on recycled paper
SECTION 6 – COMMISSIONING
Cooke Industries - Phone: +64 9 579 2185 Email: sales@cookeindustries.co.nz Web: www.cookeindustries.co.nz
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