1
Refrigerating Specialties Division
GAS POWERED
SUCTION STOP VALVE
Type CK-5-DN
Port Size 32mm to 100mm (1¼” - 4”)
FOR AMMONIA, R22, R502, R134a, R404a
AND OTHER COMMON REFRIGERANTS
FEATURES
• Normally Open
• Low Pressure Drop
• Manual Opening Stem
• Integrated Pilot Solenoid on 32mm to 100mm
(1-1/4" to 4") Sizes
• Use in Vertical or Horizontal Line
• Can be Installed on Side
• Design (PS): 2
8
bar (
406
psig)
• Complies with Pressure Equipment Directive 97/23/EC
BULLETIN DN50-23
B
Type CK5-DN
January 2007
Installation and Service Information
I S O 9 0 0 1 C E R T I F I E D
DESCRIPTION
These piston-type, discharge gas powered, normally open,
heavy duty, semi-steel bodied valves are built with control
precision. The 32mm through 100mm (1-1/4" through 4", Fig.
1) port size valves are equipped with an attached modular
pilot solenoid, A2D pilot regulator, and manual lift stem. The
32mm (1-1/4") port size has a PTFE main seat; the 40mm
(1-5/8") port and larger have a metal to metal seat.
PURPOSE
The purpose of the CK-5 gas-powered suction stop valve is
to provide the normal operating features of the R/S CK-2 stop
valve. In addition, this unique control valve incorporates a
built-in mechanical fail-safe feature which prevents the
undesirable effects of an immediate opening of the valve in
the event of an electrical power failure while the evaporator is
in defrost.
Along with the standard R/S type CK-2 gas-powered suction
stop valve, the CK-5 is typically used for low temperature
applications in wet return lines in liquid recirculation systems
or on both liquid legs and gas retur n legs of flooded
evaporators. Due to its normally open construction, pressure
drop is minimal in suction or wet return applications. In
addition, on flooded evaporators normal gravity circulation is
unrestricted. For gravity flooded evaporators, both valves
should be installed with their flow arrows pointing towards the
surge drum.
PRINCIPLES OF OPERATION
For closing of the CK-5 valve, high pressure gas from an
external source is admitted through the pilot solenoid valve to
the top of the piston. The gas pressure acting on the piston
forces it down, compressing the opening spring, firmly seating
the valve’s seat bead. The valve will not close unless pressure
above the piston exceeds the downstream pressure by at least
5 psi (0.35 bar).
After the termination of the hot gas injection period, any style
of suction stop valve must reopen in order for refrigeration to
resume. For the CK-5 to open, the valve’s pilot solenoid
de-energizes, thereby interrupting the pilot stream flow of
discharge gas to the top of the valves piston. The main valve
will continue to remain closed, however, since residual
pressure in the coil is transmitted through passage N, through
the pilot regulator to the top of the piston. [Note: The pilot
regulator should be adjusted to maintain a minimal set point,
approximately 10 psi.] Under a standard defrost sequence
for most low temperature evaporators, a “bleed down” or vent
solenoid will energize to slowly equalize pressures between
the coil and the suction line. It is imperative to incorporate a
310229
