The Alco Main Liquid Line Solenoid Valve goes
into differential mode when the coil is de-energized
or fails. Upstream liquid
➀
is forced through the
modulating valve
➁
when the upstream pressure
exceeds downstream pressure
➄
plus the spring
pressure
➃
.
In refrigeration mode, the solenoid valve
➂
is held
open allowing flow around the modulating valve
➁
.
Differential Mode Quick Test
1. Connect pressure gauges up- and downstream
of the valve.
2. All branches on the rack must be in refrigera-
tion mode.
3. Disconnect power to Solenoid.
4. Check gauges for differential.
NOTE:
Low refrigerant demand may prevent the
differential from building up to the valve’s real
setting.
September 1, 1997
P/N 401789
6 - 5
HUSSM ANN CORPORATION • BRIDGETON, M O 63044-2483 • Printed in USA
Downstream pressure
+ spring pressure
= upstream pressure.
1
5
3
4
2
1
5
3
4
2
Differential Mode - Coil De-energized
Refrigeration Mode - Coil Energized
Figure 6-6 — Alco Main Liquid Line
Solenoid
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