Vilter VSM 71-701 Operation And Service Manual Download

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Installation

In making up joints for steel pipe, the following
procedures should be followed:

For threaded connections, all threads on the pipe
and fitting should be carefully cleaned to remove
all traces of grease or oil. Threads should then be
wiped dry with a lintless cloth. Only thread fill-
ing compounds suitable for refrigeration service
should be used for making steel pipe joints. These
compounds should be used sparingly, and on the
pipe only. Do not put any on the first two threads
to prevent any of the compound from entering the
piping system. Acetylene or arc welding is fre-
quently used in making steel pipe joints, however,
only a skilled welder should attempt this kind of
work. Take care to see no foreign materials are
left in the pipes and remove all burrs formed when
cutting pipe.

It is important to avoid short, rigid pipe lines that
do not allow any degree of flexibility. This must
be done to prevent vibration being transmitted
through the pipe lines to the buildings. One
method of providing the needed flexibility to ab-
sorb the vibration is to provide long lines that are
broken by 90° Ells in three directions.

Smaller Halocarbon and Hydroflourocarbon in-
stallations use copper pipes with solder type fit-
tings where possible. The use of screw type fit-
tings in Halocarbon systems should be held to an
absolute minimum, as these refrigerants, due to
their physical properties, will leak through screw
type joints.

When drawn copper tubing is used for Halocar-
bon lines, type “K” or “L” conforming to ASTM
B88 should be used. Soft annealed copper tubing
conforming to ASTM B280 can also be used for
tube sizes not larger than 1-3/8" in outside diam-
eter. These requirements are in accordance with
the mechanical code for refrigeration ANSI B9.1-
1971. The type of copper tubing to be used for a
given pressure is dependent on the strength of the
copper at the design temperature. Some local
codes forbid the use of Type “L”. Therefore, be-
fore installation, be sure to check local require-
ments. Never use type “M” as it does not have
adequate wall thickness to withstand the operat-
ing pressures. In selecting fittings for Halocar-

bon piping, only wrought copper fittings should
be used. Cast fittings as used for water service
are porous and will allow the refrigerant to es-
cape. Note this exception: In larger pipe sizes,
wrought fittings are not available. However,
specially tested cast fittings are available and
these may be used with complete safety.

In larger pipe sizes, wrought fittings are not avail-
able. However, specially tested cast fittings are
available and these may be used with complete
safety.

When soldering copper tubing joints, only sil-
ver solder should be used for Refrigerant-22 ser-
vice. Soft solder such as “50-50” should never
be used, as its melting point is to low, lacks me-
chanical strength, and tends to break down
chemically in the presence of moisture.

A second method would be to install flex-
ible pipe couplings as close to the compressor
unit as possible with connections run in two dif-
ferent directions, 90° apart. These flexible con-
nections should be installed on both the high and
low side lines of the compressor unit.

Hangers and supports for coils and pipe lines
should receive careful attention. During pro-
longed operation of the coils, they may become
coated with ice and frost, adding extra weight to
the coil. The hangers must have ample strength
and be securely anchored to withstand the vibra-
tion from the compressor and adequately sup-
port the pipe lines.

Water supply and drain connections, and equip-
ment using water, should be installed so all the
water may be drained from the system after the
plant has been shut down in cold weather. These
precautions will avoid costly damage to the
equipment due to freezing.

This information is taken from ASHRAE 15-89
and ANSI B31.5. The installing contractor
should be thoroughly familiar with these codes,
as well as any local codes.

Vilter VSM 71-701, Operation And Service Manual

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