ClimaCool IOM AR2 SERIES - Manual (Page 55)

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The ORD opens after the ORI has offered enough restriction to cause the
differential between condensing pressure and receiver pressure to exceed
20 psi . The hot gas flowing through the ORD serves to heat up the cold
liquid being passed by the ORI . Thus the liquid reaches the receiver
warm and with sufficient pressure to assure proper expansion valve
operation . As long as sufficient refrigerant charge is in the system, the
two valves modulate the flow automatically to maintain proper receiver
pressure regardless of outside ambient .
PROPER SELECTION OF HPC VALVES — To ensure proper
performance, head pressure control valves must be selected and applied
correctly . This is covered thoroughly in Bulletin 90-30 . However, proper
installation procedures are equally important .
VALVE LOCATION/PIPING SUGGESTIONS — The ORI and
ORD valves can be installed in horizontal or vertical lines, whichever
best suits the application, and permits easy accessibility of all valves .
Consideration should be given to locating these valves so they do not
act as an oil trap and so solder cannot run into the internal parts during
brazing . Precautions should also be taken to install the valves with the
flow in the proper direction . The ORI valve CANNOT be installed in
the discharge line for any reason.
Figure 4 is a piping schematic only to illustrate the general location
of the ORI, and ORD valves in the system . ClimaCool recommends
that recognized piping references be consulted for assistance in piping
procedures . ClimaCool is not responsible for system design, or for
misapplication of its products . If these valves are applied in any manner
other than described in this bulletin, the ClimaCool warranty is void .
The inlet connections on the ORI-10 valves should be sized the same as
the outlet of the condenser where possible . The ORD-4 is available with
5/8” ODF and 7/8” ODF solder connections . On systems with discharge
lines smaller than 5/8” OD, the bypass line can be the same size as the
discharge line and the ORD-4 connections can be bushed down . If the
system capacity is greater than any of the head pressure control valves
ratings, these valves can be applied in parallel .
VALVE STRAINERS – Catch-All ® filter-driers – See·All ® moisture
and liquid indicator — Just as with any refrigerant flow control device,
the need for an inlet strainer is a function of system cleanliness and
proper installation procedures . When the strainer is used with the ORI,
the tubing is inserted in the valve connection until the tubing and strainer
flange ring are up against the tubing stop, thus locking the strainer in
place . See Below:
BRAZING PROCEDURES — Any of the commonly used brazing
alloys for high side usage are satisfactory . However, when soldering
or brazing, it is very important that the internal parts be protected by
wrapping the valve with a WET cloth to keep the body temperature
below 250°F for the ORI; and, 300°F for the ORD-4 . Also, when using
high temperature solders, the torch tip should be large enough to avoid
prolonged heating of the copper connections . And, always direct the
flame away from the valve body .
TEST and OPERATING PRESSURES — Excessive leak testing or
operating pressures may damage these valves and reduce the life of the
operating members . For leak detection an inert dry gas, such as nitrogen
or CO2, may be added to an idle system to supplement the refrigerant
pressure .
CAUTION: Inert gases must be added to the system carefully through
a pressure regulator. Unregulated gas pressure can seriously damage
the system and endanger human life. Never use oxygen or explosive
gases.
The table below lists the maximum values each valve can withstand
without damage . Precautions must be taken to keep test or operating
pressures below these values .
VALVE SETTINGS and ADJUSTMENT — A complete discussion
on pressure settings is given in the Application Section of Bulletin 90-30 .
To determine the proper setting or a specific system, that section should
be reviewed .
Type Valve
Maximum
Pressure
Rated
PSIG
ORI-10 65/225 H 450
0 5 4 4 - D R O
Head Pressure Control Valve Operation ORI/ORD