Hussmann Super Plus - Page 101

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 Te m p e r a t u r e , 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
1 0
O
F or more below its saturation temperature
for the High Side Pressure (Reading 2), the sys-
tem should be in Surge around the Receiver.
The pilot valve operates ± 5˚F accuracy.
For example, a thermometer is attached to the
liquid return line at the pilot valve bulb, and a
pressure gauge is hooked up to the Liquid
Return Line up stream of the Flooding Va l v e .
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 tem-
perature of 108
O
F. If the Liquid Return Line
Temperature (Reading 1) is 98
O
F, the refriger-
ant 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 center hose of a manifold. Connect the
high and low side hoses to respective pressure
sources. Operate the main valve through the
gauge set.
HUSSMANN CORPORATION • BRIDGETON, MO 63044-2483 • Printed in USA
CONTROL VALVES Revised August 1, 1996
7 - 14
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