Technical information

Page: 34
VL Series Portable Chillers, 2 to 40 Tons UGH021/0301
5.4 SOLENOID VALVE SERVICE
A. VLA units with the water make-up
system use a solenoid valve (figure
5.4A) to regulate the level in the
reservoir tank. The solenoid valve is
controlled by the float switch.
B. Generally, solenoid valves fail due
to poor water quality, low water
flow, or defective valve elements.
C. The operator should follow this
procedure to service the make-up
solenoid valve:
1. Disengage process operations according to the procedure
outlined in section 3.4. The operator must be certain
process fluid temperature is under 100°F and pressure is
relieved (pressure gauge reads “0”) and water system flow
is shut off and all pressure relieved.
2. Disengage main power supply. The operator must verify the
POWER light on the display is “off”.
3. Remove or open any access cover panel and set aside to
gain access to the solenoid valve.
4. The operator must be certain all water supply system
pressure is relieved.
5. Identify the retaining screw (figure 5.4B) on the solenoid
valve coil. Remove the screw. Keeping all electrical
connections intact, lift the coil off of the enclosure tube and
set aside.
6. Use a pair of channel lock pliers or a pipe wrench to
separate the bonnet assembly from the valve body. The
plunger is “loose” inside the enclosing tube. Be certain it is
retained in the enclosure tube as the bonnet is removed
(figure 5.4C).
7. Identify the diaphragm
assembly. Gently remove
the assembly from the
valve body (figure 5.4D).
8. Identify the mesh screen.
Gently removed the mesh
Coil
Figure 5.4B
Retaining screw
Typical water make-up
solenoid valve
Figure 5.4A