11
F100d
JAN 2011
CONTROL VALVES
Function of control valves: Provide hot gas to the
coil without liquid slug shocks, close the suction so
pressure can build-up, permit condensed refrigerant
liquid to exit the coil, control the pressure to a level
above freezing equivalent, and after defrost return
the coil gradually to plant suction pressure. Control
valves are available in ¾” thru 6” (20 mm thru 150 mm)
port sizes, unless otherwise stated.
HS8A SOLENOID VALVE
Normally spring closed, this valve opens
wide when energized. Ideally suited for
use as a soft gas, liquid or hot gas supply
valve. Available in ½” (13 mm) port size.
Optional close-coupled strainer (shown)
and pilot lights are available.
HS7 SOLENOID VALVE
Normally spring closed, this valve opens
wide when energized. Often used as a
liquid supply, hot gas or equalize valve
Available in ¾”, 1”, 1¼” (20, 25, 32 mm)
port sizes. Optional close-coupled
strainer (shown) and pilot lights are
available.
HS4A SOLENOID VALVE
Normally spring closed, this valve opens
wide when energized. Can be used as
a liquid line supply valve or suction
solenoid valve operating at 20F (-30C) or
above. Optional close-coupled strainer
and pilot lights are available.
HCK4 IN-LINE CHECK VALVE
These in-line check valves (disc type non-
return valves) open wide for flow in arrow
direction on valve body; promptly close
when flow reversals occur. Often they
are used on the outlet side of liquid line
solenoid valves leading to evaporators
to prevent hot gas from entering during
defrost. Also they are used between drain
pans and evaporators to keep pans from
developing frost during refrigeration and
after defrost relief regulators leading
to intermediate pressure suction lines.
They can be mounted in any position and
close-coupled to other valves.
HCK2 GAS-POWERED SUCTION
STOP VALVE
This valve is normally held open via a
spring and is gas-powered to close;
requires no pressure drop to operate.
Requires a single pilot solenoid valve
to control. Typically used to close-
off evaporators from system suction,
especially below -20F (-30C).
HS9B GAS-POWERED SOLENOID
VALVE
This valve uses a remote gas or liquid
pressure source to close; requires no
pressure drop to operate. Dual pilot
solenoid valve assembly controls opening
and closing of valve without internal bleed
to suction. This type of valve is often
used to shut-off liquid and gas legs of
gravity flooded evaporators .
HA4AD DUAL PRESSURE
REGULATOR
Regulates (evaporator) pressure at a
setting when energized, and at a higher
setting when de-energized. Used for
defrost pressure relief and pressure
control.
HA4AK RESEATING RELIEF
REGULATOR
Used for defrost relief to suction. This
control opens when system upstream
pressure is above the tagged and sealed
set point pressure, and repeatedly
reseats after operation.
HA4AS REGULATOR WITH
ELECTRIC SHUT-OFF
This control is commonly used for
temperature control or defrost. Regulates
at its set-for pressure when energized;
when de-energized, valve closes tight
regardless of pressure setting.
HA4AB REGULATOR WITH
ELECTRIC WIDE OPENING
Commonly regulates for defrost or
temperature, but opens wide for maximum
cooling or equalizing. Regulating at set
pressure when de-energized; regulator
opens wide when energized.
HA4AL DIFFERENTIAL
PRESSURE REGULATOR
Used commonly as liquid pump relief.
Avoids high discharge pressure from
developing when flow becomes restricted
due to multiple evaporator s being
in defrost at one time. This control
modulates to ma int a in the set-for
difference between inlet and outlet
pressure.
HA4AO OUTLET PRESSURE
REGULATOR
Controls outlet pressure by opening as
downstream pressure falls below setting.
Used to limit hot gas pressure supply in
defrosting evaporators in conjunction
with defrost condensate liquid drainers
or for regulating pressure in hot gas
remains. Can be combined with electric
shut-off, dual or wide opening features.
HA4AD
HA4AK
HA4AS
HA4AB
HA4AL
HA4AO
HS8
HS4A
HS7
HCK4
HCK2
HS9B
