Testing Valve Operation
General
When taking readings, account for liquid line
drop, gauge error, and thermometer accuracy.
Three measurements are required to determine if
the Valve is working properly.
Reading 1. Liquid Return Line Temperature, at the
pilot valve bulb.
Reading 2. High Side Pressure, up stream of the
Flooding Valve.
Reading 3. Autosurge Valve Chamber Pressure,
through its Schrader Valve.
Pilot Valve
When the Liquid Temperature (Reading 1) is 10
O
F
or more below its saturation temperature for the
High Side Pressure (Reading 2), the system should
be in Surge around the Receiver. The pilot valve
operates ± 5ÞF accuracy.
For example, a thermometer is attached to the liq-
uid return line at the pilot valve bulb, and a pres-
sure gauge is hooked up to the Liquid Return Line
up stream of the Flooding Valve. The gauge face at
the right shows a pressure of 220 psig (Reading 2).
According to the gauge face, R-22 would have a
saturated liquid temperature of 108
O
F. If the
Liquid Return Line Temperature (Reading 1) is
98
O
F, the refrigerant has 10
O
F of subcooling.
Because of the ±5
O
F accuracy of the pilot valve the
system may be in Surge as soon as 103
O
F is
reached or not until 93
O
F is reached.
Determining Flow Direction
When the Autosurge Valve Chamber Pressure
(Reading 3) is five pounds or more below the
High Side Pressure (Reading 2), the valve is in
Flow through the Receiver.
For example, a pressure reading at the Liquid
Return Line of 220 psig (Reading 2), and an
Mechanical Surge Valve Chamber Pressure of 215
psig should place the system in Flow through the
Receiver.
Main Valve
To test the Main Valve, isolate the Pilot Valve and
connect the Autosurge Schrader Valve to the cen-
ter hose of a manifold. Connect the high and low
side hoses to respective pressure sources. Operate
the main valve through the gauge set.
CONTROL VALVES
September 1, 1997
6 - 14
HUSSM ANN CORPORATION • BRIDGETON, M O 63044-2483 • Printed in USA
Refrigerant R-22
Pressure Reading = 220 psig
Saturated Liquid Temperature = 108˚F
10 ˚F Subcooling = 98˚F
Operation Range of Pilot Valve =
between 93˚ and 103˚F.
10˚F Subcooling
0
50
100
150
200
250
300
350
400
450
500
R-22
0
-20 -40
20
40
50
60
70
80
90
100
110
120
130
140
150
160
-40
-20
0
10
20
30
40
50
60
70
80
90
110
120
130
140
150
R-502
30
100
Operation Range
of Pilot Valve
Figure 6-17 —Establishing Valve
Operation Range
When entering a system's high side through
a Schrader Valve, use a High Side Schrader
Valve Adapter between the Schrader Valve
and the gauge speed coupling. This will
prevent excessive refrigerant loss into the
environment and decrease the hazard of
refrigerant burn.
WARNING
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