1
Refrigerating Specialties Division
CHECK VALVE
Type CK1-DN
Port Size 20 - 150mm (3/4” -
4
”)
FOR AMMONIA, R12, R22, R502
AND OTHER COMMON REFRIGERANTS
FEATURES
• Manual Opening Stem
• Low Pressure Drop
• Piston Type Gravity Closing
• Flanged
• Design Pressure (PS): 2
8
bar (
406
psig)
• Rugged - Heavy Duty
• Complies with Pressure Equipment Directive 97/23/EC
BULLETIN DN50-10
B
Type CK1-DN
January 2007
Installation, Service and Parts Information
I S O 9 0 0 1 C E R T I F I E D
Description
These piston type, gravity closing, heavy duty check
valves are suitable for Ammonia, R-12, R-22, R-502,
other refrigerants, certain oils and or fluids approved for
use in refrigeration. All CK1 check valves are flanged
and have a manual opening stem for manual operation.
They may be ordered with male adapter rings (through
4" size) for close coupling. The 20-32 mm (3/4 - 1-1/4")
port size have a PTFE seat; larger valves have a metal
to metal seat. A minimum pressure difference of .03 bar
(0.5 psi) is required to open the valve.
Purpose
The Type CK1 Check Valves prevent backward flow of
fluid in refrigerant suction, hot gas or liquid lines. They
are recommended for compressor discharge lines, also
for liquid lines and suction lines with temperatures as
low as -30°C (-25°F).
Principles of Operation
This piston type check valve opens by the pressure
difference between valve inlet and outlet. The pressure
difference must be a minimum of .03 bar (0.5 psi).
When upstream pressure exceeds downstream
pressure, the pressure on the bottom side of the
piston-main valve will lift the assembly and allow flow
through the valve. On opening, pressure above the
piston-main valve assembly will be relieved through the
piston bleed hole, permitting the piston to travel its full
vertical distance and open the valve to its full open
position.
When upstream and downstream pressures are
equalized, the weight of the piston-main valve will cause
it to drop tight against its seat bead and stop flow. Should
downstream pressure rise, the additional pressure
acting on the top of the valve seat will further assist in
seating the valve closed.
Manual Opening Stem (See Fig. 1)
If it is desired to hold open the CK1 check valve manually
this procedure should be followed. For access to the
stem, the seal cap on the bottom of the valve must be
removed. This must be done with caution as refrigerant
may be trapped inside the seal cap. Manual opening is
accomplished by turning the stem clockwise until only
the flats on the end of the stem protrude from the packing
nut. To reset for automatic operation turn the stem
counterclockwise as far as it goes. Loosen packing nut
before turning stem, and retighten after turning stem.
Fig. 1
SEAL CAP
MANUAL
OPENING
STEM
VALVE
COVER
PISTON – MAIN
VALVE ASSEMBLY
310227
