Carrier 5H - Manual (Page 8)

OIL SEPARATORS - Oil separators in the hot
gas discharge line are not recommended for gen­
eral use with Freon refrigerants. However, there
are certain systems where the protection afforded
by a separator is desirable, notably those systems
employing flooded evaporators. For a more com­
plete discussion see Carrier's System Design
Manual.
CRANKCASE OIL HEATERS-Crankcase oil heat­
ers are availablefor all 5F,Hcompressors.These
heaters keep the crankcase warm during off cycles
and thus minimize refrigerant absorption in the
oil.
Refer to the 5F,H Installation Manual for
installation and wiring instructions.
INTERCONNECTION OF COMPRESSORS - All
5F,H compressors except 5F20 and SFSOarefur-
nished with removable handhole cover plates on
each crankcase. When field interconnection is
desired, these removable handhole cover plates
can be removed and replaced by special cover
plates with tapped openings. These tapped cover
plates have connections for both oil and gas equal­
izing lines. For interconnection of the 5F20 and
5F30 compressors it is necessary to drill and tap
the crankcase as shown in the 5F,H Installation
Instruction Manual.
Because the 5F,H duplex units will usually
be interconnected, these machines are equipped
with tapped cover plates and interconnected at
the factory.
VIBRATION ISOLATORS - A standard vibration
isolation package is available for each 5F,H com­
pressor. This consists of a standard rubber in
shear and compression type mounting which gives
an average static deflection of approximately
1 /8 inch and provides reasonably good vibration
isolation at 1750 rpm.
Isolation packages are recommended for use
on all compressor and condensing units. They are
valuable not only on upper floors in reducing
vibration transfer to structure, but also when
installed on cement floors they prevent misalign­
ment of the drive shaft due to pull down on an
uneven floor.
When compressors are run at slower speeds or
when superior isolation is desired, isolators are
available on the market which give approximately
3/8 inch deflection. Table 8 indicates the estimated
weight distribution, using a nominal horsepower
motor, on each leg of the condenser or compres­
sor unit. For duplex units the weight is approxi­
mately the same on each leg.
MUFFLERS - Four standard mufflers cover the
entire range of all 5F,H compressors. It is rec­
ommended that these mufflers be installed when­
ever compressors are used with remotely located
water-cooled or evaporative condensers.
SECTION
PAGE
DATE
5F,H-1XA
8
10-66 Printed in U.S.A.
Mufflers are not usually necessary with the
smaller 5F compressors and their use is recom­
mended only when the application is critical with
respect to quietness of operation.
Each piping package available to convert 5H
compressor units to condensing units includes a
standard muffler of the appropriate size.
Pressure drop thru these mufflers is about
1 /2 psi at 40 F suction and 105 F discharge with
the following loadings; 5 tons with 5F20 muffler,
15 tons with 5F40 muffler, 35 tons with the 5H40
muffler, and 100 tons with the 5H120 muffler.
CAPACITY CONTROL - A cylinder unloading type
of capacity control package is available for 5F20
and 5F30 compressor. It is standard equipment
on the 5F40 and larger compressors.
The cylinder unloading mechanism is powered
by the compressor force feed lubricating system.
This feature assures unloading of all controlled
cylinders at starting regardless of the position
of the capacity control valve, since the suction
valves will be held in the open position until the
lubricating oil pressure reaches its normal op­
erating level.
The compressors as furnished from the fac­
tory will have the capacity control arranged for
capacity reduction in response to suction pres­
sure. An external adjusting stem is provided to
set the control point and maintain the desired suc­
tion pressure. The control point is adjustable from
0 to 50 psig suction pressure. The differential over
the complete range at any temperature level is
7 psig with Refrigerant 12 and Refrigerant 500.
An 11-lb spring (for use on 5F40 and larger units)
is furnished with the compressor which, when
used, results in an adjustable control point from
0 to 85 psig with an 11 psig range. It should be
inserted in the capacity control valve whenever
R-22 or R-502 is used.
With this arrangement the suction pressure
will not drop below the control set point minus
the differential within the range of capacity steps
since the compressor will unload to balance its
capacity with the evaporator load.
The power elements and valve lifting mechan­
isms are identical on all 5F,H compressors.
However, when using capacity control, various
methods are used to activate the power elements.
See Table 10 for the unloading steps and power
requirements at each step.
S U P E R S E D E S
SECTION
5F,H-1X
PAGES 1-42
DATE 11-63