BRANCH LIQUID LINE
SOLENOID VA LV E S
The Branch Liquid Line Solenoid Valve closes
o ff refrigerant supply to the evaporator, yet
allows back flow of refrigerant into the Liquid
Manifold for Koolgas Defrost.
When the Solenoid is de-energized the Valve
Port ➀ is held closed. Higher Pressure ➄
upstream fills the Valve Chamber ➂ t h r o u g h
the Equalizing Port ➃ , keeping the Va l v e
closed.
In refrigeration the Valve Port ➀ opens,
emptying Valve Chamber ➂ through the
Check Valve ➁ faster than the Equalizing Port
➃ can fill it. Higher Pressure ➄ u p s t r e a m
forces the Valve open.
During Defrost, Valve Port ➀ opens,
removing kick spring force from the valve.
Higher Pressure ➄ downstream back flows,
closing the Check Valve ➁ and forcing the
Valve up. Equalizing Port ➃ allows Va l v e
Chamber ➂ pressure to escape upstream.
N o t e : The Solenoid of the branch valve is
e n e rgized during refrigeration and for back
flow during defrost.
Troubleshooting Branch Liquid Line
Solenoid Valves
HUSSMANN CORPORATION • BRIDGETON, MO 63044-2483 • Printed in USA
CONTROL VALVES Revised August 1, 1996
7 - 6
Malfunction Cause Action
Fails to Open Dirt plugging valve port Disassemble and clean
or equalizing port
Solenoid not energized
-bad solenoid Replace solenoid
-circuit open Find and repair open
Fails to close Dirt in valve port Clean or replace
or equalizing port
Barrel or piston scored Replace
Dirt in piston chamber, causing drag Clean or replace
Figure 7-7
Branch Liquid Line with Back Flow
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