Bohn H-IM-CU Installation Manual
Installation and
Operations Manual
H-IM-CU August 2008 Part No. 25008101
Replaces None. Information formerly included in H-IM-64L.
Condensing
Units
Table of Contents
General Safety Information...............................................................................2
Inspection ...............................................................................................................2
Warranty Statement ............................................................................................2
Space and Location Requirements ...............................................................3
Remote and Water Cooled Condensing Units Requirements ..............4
City & Tower Water Connections .....................................................................4
Condensing Unit Rigging and Mounting ....................................................5
Head Pressure Control ........................................................................................6
Refrigerant Oils ......................................................................................................7
Phase Loss Monitor ..............................................................................................8
Recommended Refrigerant Piping Practices .............................................8
Refrigeration Pipe Supports ............................................................................8
Suction Lines ..........................................................................................................8
Liquid Lines ............................................................................................................9
Hot Gas Defrost Systems ...................................................................................9
Unit Cooler Piping ............................................................................................. 10
Line Sizing Tables ........................................................................................10-13
Evacuation and Leak Detection ...................................................................14
Refrigerant Charging Instructions ............................................................... 14
Field Wiring .......................................................................................................... 14
Check Out and Start Up ..................................................................................15
Operational Check Out .................................................................................... 16
System Balancing - Compressor Superheat ............................................. 16
General Sequence of Operation ..................................................................17
Electric Defrost Troubleshooting ................................................................. 17
System Troubleshooting Guide ....................................................................18
Preventive Maintenance Guidelines ...........................................................19
Typical Wiring Diagrams ...........................................................................20-23
InterLink™ Replacement Parts ...................................................................... 24
H-IM-CU-0808 | Version 000
General Safety Information
Installation and maintenance to be performed only by qualied
1.
personnel who are familiar with this type of equipment.
Some units are pressurized with dry air or inert gas.
2.
All units must be evacuated before charging the system with refrigerant.
WARNING: Refrigerant can be harmful if it is inhaled. Refrigerant must be used and recovered responsibly.
Failure to follow this warning may result in personal injury or death.
Inspection
Responsibility should be assigned to a dependable individual at the job site
to receive material. Each shipment should be carefully checked against the
bill of lading. The shipping receipt should not be signed until all items listed
on the bill of lading have been accounted. Check carefully for concealed
damage. Any shortage or damages should be reported to the delivering
carrier. Damaged material becomes the delivering carrier’s responsibility,
and should not be returned to the manufacturer unless prior approval is
given to do so. When uncrating, care should be taken to prevent damage.
Heavy equipment should be left on its shipping base until it has been
moved to the nal location. Check the serial tag information with invoice.
Report any discrepancies to your Heatcraft Refrigeration Products Sales
Representative.
Warranty Statement
Seller warrants to its direct purchasers that products, including Service Parts,
manufactured by SELLER shall be of a merchantable quality, free of defects in
material or workmanship, under normal use and service for a period of one
(1) year from date of original installation, or eighteen (18) months from
date of shipment by SELLER, whichever rst occurs. Any product covered by
this order found to Seller’s satisfaction to be defective upon examination at
Seller’s factory will at SELLER’s option, be repaired or replaced and returned
to Buyer via lowest common carrier, or SELLER may at its option grant Buyer
a credit for the purchase price of the defective article. Upon return of a
defective product to SELLER’s plant, freight prepaid, by Buyer, correction of
such defect by repair or replacement, and return freight via lowest common
carrier, shall constitute full performance by SELLER of its obligations
hereunder.
SELLER shall have no liability for expenses incurred for repairs made by
Buyer except by prior, written authorization. Every claim on account of
breach of warranty shall be made to SELLER in writing within the warranty
period specied above – otherwise such claim shall be deemed waived.
Seller shall have no warranty obligation whatsoever if its products have
been subjected to alteration, misuse, negligence, free chemicals in system,
corrosive atmosphere, accident, or if operation is contrary to SELLER’s or
manufacturer’s recommendations, or if the serial number has been altered,
defaced, or removed.
Make sure that all eld wiring conforms to the requirements
3.
of the equipment and all applicable national and local codes.
Avoid contact with sharp edges and coil surfaces.
4.
They are a potential injury hazard.
Make sure all power sources are disconnected before any
5.
service work is done on units.
The forgoing is in lieu of all other warranties, express or implied,
notwithstanding the provisions of the uniform commercial code, the
Magnuson-Moss Warranty - Federal Trade Commission Improvement Act, or
any other statutory or common law, federal or state.
SELLER makes no warranty, express or implied, of tness for any particular
purpose, or of any nature whatsoever, with respect to products manufactures
or sold by seller hereunder, except as specically set forth above and on
the face hereof. It is expressly understood and agreed that SELLER shall not
be liable to buyer, or any customer of buyer, for direct or indirect, special,
incidental, consequential or penal damages, or for any expenses incurred by
reason of the use or misuse by buyer or third parties of said products. To the
extent said products may be considered "consumer products," As dened
in Sec. 101 of the Magnuson-Moss Warranty - Federal Trade Commission
Improvement Act, SELLER makes no warranty of any kind, express or implied,
to "consumers," except as specically set forth above and on the face hereof.
The following conditions should be adhered to when installing this unit to
maintain the manufacturers warranty:
System piping must be in accordance with good refrigeration
a)
practices.
Inert gas must be charged into the piping during brazing.
b)
The power supply to the unit must meet the following conditions:
c)
A. Three phase voltages must be +/- 10%
of nameplate ratings. Single phase must be
within +10% or -5% of nameplate ratings.
B. Phase imbalance cannot exceed 2%.
All control and safety switch circuits must be properly connected
d)
according to the wiring diagram.
The factory installed wiring and piping must not be changed
e)
without written factory approval.
All equipment is installed in accordance with
f)
Heatcraft Refrigeration Products specied minimum clearances.
MOTOR COMPRESSORS:
Motor compressors furnished by SELLER are subject to the standard
warranty terms set forth above, except that motor compressor replacements
or exchanges shall be made through the nearest authorized wholesaler
of the motor compressor manufacturer (not at SELLER’s factory) and no
freight shall be allowed for transportation of the motor compressor to and
from the wholesaler. The replacement motor compressor shall be identical
to the model of the motor compressor being replaced. Additional charges
which may be incurred throughout the substitution of other than identical
replacements are not covered by this warranty. An optional, non assignable,
four (4) year extended compressor warranty may be purchased within the
boundaries of the United Sates of America, its territories and possessions,
and Canada. With this extended compressor warranty, replacements are
administered by an authorized compressor distributor only. Replacements
within the rst year of the warranty area available through the distributor;
the second through fth years, the purchaser must submit a proof-ofpurchase of a compressor and supply it to Heatcraft Refrigeration Products
Warranty Claims for reimbursement.
Seller makes no express warranties except as noted above. All implied
warranties are limited to the duration of the Express Warranty. Liability for
incidental and consequential damages is excluded.
2
© 2008 Heatcraft Refrigeration Products LLC
Space and Location Requirements for
W
MIN.
W
AIR FLOW
W
AIR FLOW
W
W
W
MIN.
W
AIR FLOW AIR FLOW
W
Clearance for multiple units placed side by side
AIR FLOW AIR FLOW
AIR FLOW
W
W
MIN.
W
MIN.
1 FT. MIN.
Clearance for fence enclosures
AIR FLOW
2W
MIN.
2W
MIN.
10 FT. MAX.
W
Clearance for units in pits
AIR FLOW
STACK
(SUPPLIED BY OTHERS)
W
W
MIN.
AIR FLOW
Clearance from walls or obstructions
AIR FLOW
AIR FLOW
W
W
AIR FLOW
W
AIR FLOW
AIR FLOW
W W
AIR FLOW
Air Cooled Condensing Units and Remote Condensers
The most important consideration which must be taken into account when
deciding upon the location of air-cooled equipment is the provision for a
supply of ambient air to the condenser, and removal of heated air from the
condensing unit or remote condenser area. Where this essential requirement
is not adhered to, it will result in higher head pressures, which cause poor
operation and potential failure of equipment. Units must not be located
in the vicinity of steam, hot air or fume exhausts. Corrosive atmospheres
require custom designed condensers.
Another consideration which must be taken is that the unit should be
mounted away from noise sensitive spaces and must have adequate support
to avoid vibration and noise transmission into the building. Units should be
mounted over corridors, utility areas, rest rooms and other auxiliary areas
where high levels of sound are not an important factor. Sound and structural
consultants should be retained for recommendations.
Figure 1. Space and Location Requirements for Condensing Units
Walls or Obstructions
The unit should be located so that air may circulate freely and not be
recirculated. For proper air ow and access all sides of the unit should be
a minimum of “W” away from any wall or obstruction. It is preferred that
this distance be increased whenever possible. Care should be taken to
see that ample room is left for maintenance work through access doors
and panels. Overhead obstructions are not permitted. When the unit is
in an area where it is enclosed by three walls the unit must be installed
as indicated for units in a pit.
Walls or Obstructions for Horizontal Air Flow
Units in Pits
The top of the unit should be level with the top of the pit, and side
distance increased to “2W”.
If the top of the unit is not level with the top of pit, discharge cones or
stacks must be used to raise discharge air to the top of the pit. This is a
minimum requirement.
Multiple Units
For units placed side by side, the minimum distance between
units is the width of the largest unit. If units are placed end to
end, the minimum distance between units is 4 feet.
Multiple Units with Horizontal Air Flow
Decorative Fences
Fences must have 50% free area, with 1 foot undercut, a “W”
minimum clearance, and must not exceed the top of unit. If these
requirements are not met, unit must be installed as indicated for
“Units in pits”.
NOT RECOMMENDED
* “W” = Total width of the condensing unit
3
Requirements for Remote and Water Cooled
Condensing Units
General Installation
The indoor compressor units are designed to be used with a remote
condenser. The water cooled units are similar, except that they have an
integral water cooled condenser. Inlet and outlet water connections are to
be made in the eld. On units having a compressor water jacket, incoming
water shall be routed through the jacket prior to entering the condenser. For
cleaning purposes, condenser end plates can be removed to give access to
the water tubes. Cleaning is accomplished by a simple spiral tool powered
by an ordinary electric drill. During installation, allow space for cleaning the
condenser. Commercial equipment of this type is intended for installation
by qualied refrigeration mechanics.
Typical Arrangements
Diagram 1 illustrates a typical piping arrangement involving a remote
condenser located at a higher elevation, as commonly encountered when
the condenser is on a roof and the compressor and receiver are on grade
level or in a basement equipment room.
In this case, the design of the discharge line is very critical. If properly sized
for full load condition, the gas velocity might be too low at reduced loads
to carry oil up through the discharge line and condenser coil. Reducing the
discharge line size would increase the gas velocity suciently at reduced
load conditions; however, when operating at full load, the line would be
greatly undersized, and thereby creating an excessive refrigerant pressure
drop. This condition can be overcome in one of two of the following ways:
The discharge line may be properly sized for the desired pressure
1.
drop at full load conditions and an oil separator installed at the
bottom of the trap in the discharge line from the compressor.
A double riser discharge line may be used as shown in
2.
Diagram 2. Line “A” should be sized to carry the oil at minimum
load conditions and the line “B” should be sized so that at the
full load conditions both lines would have sucient ow velocity
to carry the oil to the condenser.
Water Regulating Valve
Using this control on the water cooled condensing units, the head pressure
can be maintained by adjusting the ow of water through the condenser
section. This type control is most often located on the water entering side of
the condenser and is regulated by the refrigerant condensing pressure.
Subcooler
Diagrams 1 and 2 below show typical subcooler piping. Diagram 1 is the
preferred connection with receiver as it provides maximum subcooling.
Diagram 2 may be used if the receiver is located far from the condenser.
Notes:
All oil traps are to be as short in radius as possible. Common practice is
1.
to fabricate the trap using three 90 degree ells.
Pressure relief valves are recommended at the condenser for protection
2.
of the coil.
A pressure valve at the high point in the discharge line is recommended
3.
to aid in removing non-condensables.
The placement of a subcooler should be that it does not interfere with
4.
normal airow of the condenser. Increased static of the unit could cause
a decrease in system capacity and fan motor damage.
Diagram 1 Diagram 2
City & Tower Water Connections
In the refrigeration industry “City” and “Tower” are designations of
temperature and ow conditions, not applications. The term “City” refers
to operating conditions where incoming water is 75˚F, and condensing
temperature is 105˚F. “Tower” refers to a higher temperature relationship
which is normally 85˚F, incoming water and 105˚F condensing temperature.
Water circuits in some condenser models provide a center, or Tower, outlet
connection to allow divided inlet water ow. This extra water port reduces
water velocity, water pressure drop, and condenser wear in applications such
as cooling towers where higher inlet temperatures and water ows occur.
Water Connections for City
For City water (open system) high pressure applications, the Tower
connections is plugged.
Water Connections for Tower
For Tower usage and low pressure applications, both normal water
connections will be used as inlets and the tower connection as an outlet.
Figure 2. Water Connections
4
Condensing Unit Rigging and Mounting
Rigging holes are provided on all units. Caution should be exercised when
moving these units. To prevent damage to the unit housing during rigging,
cables or chains used must be held apart by spacer bars. The mounting
platform or base should be level and located so as to permit free access of
supply air.
Ground Mounting
Concrete slab raised six inches above ground level provides a suitable base.
Raising the base above ground level provides some protection from ground
water and wind blown matter. Before tightening mounting bolts, recheck
level of unit. The unit should in all cases be located with a clear space in all
directions that is at a minimum, equal to the height of the unit above the
mounting surface. A condensing unit mounted in a corner formed by two
walls, may result in discharge air recirculation with resulting loss of capacity.
Roof Mounting
Due to the weight of the units, a structural analysis by a qualied engineer
may be required before mounting. Roof mounted units should be installed
level on steel channels or an I-beam frame capable of supporting the weight
of the unit. Vibration absorbing pads or springs should be installed between
the condensing unit legs or frame and the roof mounting assembly.
Access
Provide adequate space at the compressor end of the unit for servicing.
Provide adequate space on the connection side to permit service of components.
Spring Mounted Compressor
Compressors are secured rigidly to make sure there is no transit damage.
Before operating the unit, it is necessary to follow these steps:
Remove the upper nuts and washers.
a)
Discard the shipping spacers.
b)
Install the neoprene spacers. (Spacers located in the electrical
c)
panel or tied to compressor.)
Replace the upper mounting nuts and washers.
d)
Allow 1/16 inch space between the mounting nut/washer and
e)
rubber spacer. Mounting spring must not be fully compressed
when mounting nut is properly installed. See Figures 3 and 5.
Figure 3. Spring Mount
Figure 4. Solid Mount for Mobile or Deep Sump Application
Rigid Mounted Compressor
Some products use rigid mounted compressors. Check the compressor
mounting bolts to insure they have not vibrated loose during shipment. See
Figure 4.
Figure 5. Spring Mount
5
Head Pressure Control
Several types of head pressure control systems are available on
condensing units:
Dual Valve System. (See section on operation and adjustment.)
A.
Single Valve system. No adjustments are necessary.
B.
(See section on operation.)
Ambient Fan Cycle Control. (See section on operation
C.
and adjustment.)
C. Ambient Fan Cycle Control
This is an automatic winter control method which will maintain a condensing
pressure within reasonable limits by cycling fan motors in response to
outside air temperature. The thermostat(s) should be eld adjusted to shut
o the fan when the condensing temperature is reduced to approximately
90˚F. Table 1 lists approximate settings for several system T.D.’s. These settings
are approximate as they do not take into account variations in load.
A. Dual Valve System
The system employs an ORI (open on rise of inlet pressure) valve and an ORD
( open on rise of dierential pressure) valve. The high pressure discharge gas
is introduced above the liquid in the receiver tank. The receiver discharge is
regulated by the ORI valve.
The discharge pressure of the ORI valve must be adjusted to regulate the unit
for proper operating conditions. Adjust the ORI valve shown on the following
diagram to maintain a discharge pressure of 160 to 180 PSIG.
Figure 6. Dual Valve Piping Arrangement
B. Single Valve System
The standard valve used on high pressure refrigerant systems controls
the head pressure at approximately 180 PSIG. There is no adjustment for
this valve. On low pressure refrigerant systems the valve controls pressure
at approximately 100 PSIG. For energy eciency, the 100 PSIG valve is
sometimes used on high pressure refrigerant systems.
At condensing pressures above the valve setting, ow enters Port C and
leaves Port R. When the condensing pressure falls below the valve setting,
the valve modulates to permit discharge gas to enter Port D. Metering
discharge gas into the refrigerant ow leaving the condenser produces a
higher pressure at the condenser outlet, reduces the ow, and causes the
level of liquid refrigerant to rise in the condenser. This “ooding” of the
condenser with liquid refrigerant reduces the available condensing surface,
holding the condensing pressure at the valve setting.
Table 1. Ambient Fan Cycle Thermostat Settings
Models
2-fan units: 25 65
4-fan units: 15 75
3-fan units: 25 65 55
6-fan units: 15 75 65
8-fan units: 25 65 55 40
NOTE: Cycle pairs of fans on double wide units.
Operation and Adjustment
Condensing units with dual valves require sucient charge to partially ood
the condenser during low ambient conditions.
Valve adjustment should be made with gauges connected to the discharge
port of the compressor. Adjustments should be made during mild or
low ambient conditions. Turning the valve stem “clockwise” on the ORI
valve will increase the discharge pressure, while turning the valve stem
“counterclockwise” will decrease the discharge pressure.
If adjustments are made during warm ambient conditions, it may not be
possible to adjust the regulator valve as low as desired. Readjustment may
be necessary once cooler conditions prevail.
Design Thermostat Settings
T.D. T1 T2 T3
30 60
20 70
30 60 40
20 70 60
30 60 50 30
20 70 65 50
15 75 70 60
Figure 7. Single Valve Flooding Valve Piping Arrangement
CAUTION:
Fans closest to the headers should not be cycled on standard temperature or pressure controls. Dramatic temperature and pressure changes at the
headers as a result of fan action can result in possible tube failure. Fan motors are designed for continuous duty operation.
Fan cycling controls should be adjusted to maintain a minimum of (5) minutes on and (5) minutes o. Short cycling of fans may result in a
premature failure of motor and/or fan blade.
Compressors operating below +10°F SST must have air owing over the compressor at all times when the compressor is running.
CAUTION:
Under no circumstance should all condenser motors be allowed to cycle o on one control. At least one motor shall be wired to operate at all times.
Under most circumstances, the condenser motor nearest the inlet header should remain on whenever the compressor is operating.
6
Refrigeration Oils*
With the changes that have taken place in our industry due to the CFC
issue, we have reevaluated our lubricants to ensure compatibility with the
new HFC refrigerants and HCFC interim blends oered by several chemical
producers. As a secondary criteria, it is also desirable that any new lubricant
be compatible with the traditional refrigerants such as HCFC-22 or R502. This
“backward compatibility” has been achieved with the introduction of the
Polyol ester lubricants.
Polyol Ester Lubricants
Hygroscopicity
Ester lubricants (POE) have the characteristic of quickly absorbing moisture
from the ambient surroundings. This is shown graphically in Figure 8 where
it can be seen that such lubricants absorb moisture faster and in greater
quantity than conventional mineral oils. Since moisture levels greater
than 100 ppm will results in system corrosion and ultimate failure, it is
imperative that compressors, components, containers and the entire system
be kept sealed as much as possible. Lubricants will be packaged in specially
designed, sealed containers. After opening, all the lubricant in a container
should be used at once since it will readily absorb moisture if left exposed to
the ambient. Any unused lubricant should be properly disposed of. Similarly,
work on systems and compressors must be carried out with the open time as
short as possible. Leaving the system or compressor open during breaks or
overnight MUST BE AVOIDED!
Figure 8.
Oil Types
Table 2 below summarizes which oils/lubricants are approved for use in
Copeland compressors.
Mineral Oils
The BR and Scroll compressors use Sontex 200, a “white oil”. This oil is
not suitable for low temperature applications nor is it available through
the normal refrigeration wholesalers. For eld “top-o” the use of 3GS or
equivalent, or Zerol 200TD is permissible, as long as at least 50% of the total
oil charge remains Sontex 200.
Suniso 3GS, Texaco WF32 and Calumet R015 (yellow oils) are available
through normal refrigeration wholesalers. These oils are compatible if mixed
and can be used on both high and low temperature systems.
Polyol Ester Lubricants
The Mobil EAL ARCTIC 22 CC is the preferred Polyol ester due to unique
additives included in this lubricant. ICI Emkarate RL 32S is an acceptable
Polyol ester lubricant approved for use when Mobil is not available. These
POE’s must be used if HFC refrigerants are used in the system. They are
also acceptable for use with any of the traditional refrigerants or interim
blends and are compatible with mineral oils. They can therefore be mixed
with mineral oils when used in systems with CFC or HCFC refrigerants when
Copeland compressors are used. These lubricants are compatible with one
another and can be mixed.
Alkyl Benzenes
Zerol 200TD is an alkyl benzene (AB) lubricant. Copeland recommends this
lubricant for use as a mixture with mineral oil (MO) when using the interim
blends such as R-401A, R-401B and R-402A (MP39, MP66 and HP80). A
minimum of 50% AB is required in these mixtures to assure proper oil return.
Shell MS 2212 is a 70/30 mixture of AB/MO. If this lubricant is used in a
retrot situation virtually all of the existing MO must be drained prior to
relling with the MS 2212 to assure a minimum 50% AB content.
Color
As received, the POE lubricant will be clear or straw colored. After use, it may
acquire a darker color. This does not indicate a problem as the darker color
merely reects the activity of the lubricant's protective additive.
Oil Level
During Copeland's testing of Polyol ester oil, it was found that this lubricant
exhibits a greater tendency to introduce oil into the cylinder during ooded
start conditions. If allowed to continue, this condition will cause mechanical
failure of the compressor.
A crankcase heater is required with condensing units and it must be turned
on several hours before start-up.
Oil level must not exceed 1/4 sight glass.
Table 2. Refrigeration Oils
Refrigeration Oils
POE's Mobil EAL ARCTIC 22 CC A A P
ICI (Virginia KMP) EMKARATE RL 32CF A A P
Mineral Oils Suniso 3GS P PM NOT ACCEPTABLE
Texaco WF32 P PM
Calumet RO15 (Witco) P PM
Sontex 200-LT (White Oil) (BR & Scroll Only)
Witco LP-200 P
A/B Zerol 200TD AM PM NOT ACCEPTABLE
Soltex Type AB-200 PM
P = Preferred Lubricant Choice A = Acceptable Alternative M = Mixture of Mineral Oil and Alkyl Benzene (AB) with minimum 50% AB.
*(Reprinted by permission from Copeland Corporation)
Traditional Refrigerants
HCFC-22
Interims
R401A, R401B, R402A
(MP-39, MP-66, HP-80)
HFC's
HFC-134a, R404A, R507
7
Suitable P-type oil traps should be located at the base of each
Phase Loss Monitor
The combination phase sequence and loss monitor relay protects the system
against phase loss (single phasing), phase reversal (improper sequence) and
low voltage (brownout). When phase sequence is correct and full line voltage
is present on all three phases, the relay is energized as the normal condition
indicator light glows.
Note: If compressor fails to operate and the normal condition indicator light
on the phase monitor does not glow, then the supplied electrical current
is not in phase with the monitor. This problem is easily corrected by the
following steps:
Turn power o at disconnect switch.
1.
Swap any two of the three power input wires.
2.
Turn power on. Indicator light should glow and compressor
3.
should start.
Observe motors for correct rotation.
4.
Recommended Refrigerant Piping Practices
The system as supplied by Heatcraft Refrigeration Products, was
thoroughly cleaned and dehydrated at the factory. Foreign matter may enter
the system by way of the evaporator to condensing unit piping. Therefore,
care must be used during installation of the piping to prevent entrance of
foreign matter.
Install all refrigeration system components in accordance with applicable
local and national codes and in conformance with good practice required for
the proper operation of the system.
The refrigerant pipe size should be selected from the Line Sizing Tables. The
interconnecting pipe size is not necessarily the same size as the stub-out on
the condensing unit or the evaporator.
The following procedures should be followed:
Do not leave dehydrated compressors or lter-driers on
a)
condensing units open to the atmosphere any longer than is
absolutely necessary.
Use only refrigeration grade copper tubing, properly sealed
b)
against contamination.
Suction lines should slope 1/4" per 10 feet towards
c)
the compressor.
d)
suction riser to enhance oil return to the compressor.
For desired method of superheat measurement, a pressure tap
e)
should be installed in each evaporator suction line in
the proximity of the expansion valve bulb.
When brazing refrigerant lines, an inert gas should be passed
f)
through the line at low pressure to prevent scaling and
oxidation inside the tubing. Dry nitrogen is preferred.
Use only a suitable silver solder alloy on suction and liquid lines.
g)
Limit the soldering paste or ux to the minimum required to
h)
prevent contamination of the solder joint internally. Flux only the
male portion of the connection, never the female. After brazing,
remove excess ux.
See Table 6 for discharge and liquid drain line sizes for remote
i)
condenser connections.
If isolation valves are installed at the evaporator, full port ball
j)
valves should be used.
Refrigerant Pipe Support
Normally, any straight run of tubing must be supported in at least two
1.
locations near each end of the run. Long runs require additional
supports. The refrigerant lines should be supported and fastened
properly. As a guide, 3/8 to 7/8 should be supported every 5 feet; 1-1/8
and 1-3/8 every 7 feet; and 1-5/8 and 2-1/8 every 9 to 10 feet.
When changing directions in a run of tubing, no corner should be left
2.
unsupported. Supports should be placed a maximum of 2 feet in each
direction from the corner.
Piping attached to a vibrating object (such as a compressor or
3.
compressor base) must be supported in such a manner that will not
restrict the movement of the vibrating object. Rigid mounting will
fatigue the copper tubing.
Do not use short radius ells. Short radius elbows have points of excessive
4.
stress concentration and are subject to breakage at these points.
Thoroughly inspect all piping after the equipment is in operation and
5.
add supports wherever line vibration is signicantly greater than most
of the other piping. Extra supports are relatively inexpensive as
compared to refrigerant loss.
Figure 9. Example of Pipe Support Figure 10. Condensing Unit / Compressor to Wall Support
Suction Lines
Horizontal suction lines should slope away from the evaporator toward
the compressor at the rate of 1/4 inch per 10 feet for good oil return. When
multiple evaporators are connected in series using a common suction line,
the branch suction lines must enter the top of the common suction line.
For dual or multiple evaporator systems, the branch lines to each evaporator
should be sized for the evaporator capacity. The main common line should
be sized for the total system capacity.
Suction lines that are outside of refrigerated space must be insulated. See
the Line Insulation section on page 14 for more information.
Figure 11. Suction P-Traps
Slope 1/4"
per 10 ft.
toward
compressor
Suction Line Risers
Prefabricated wrought copper traps are available, or a trap can be made
by using two street ells and one regular ell. The suction trap must be the
same size as the suction line. For long vertical risers, additional traps may
be necessary. Generally, one trap is recommended for each length of pipe
(approximately 20 feet) to insure proper oil movement. See Figure 11 for
methods of constructing proper suction line P-traps.
Figure 12. Double Suction Riser Construction
Sized for
Minimum
Sized for
Minimum
Load
Sized
for Full
Load
Load
Sized
for Full
Load
NOTE:
A suction line trap must be installed at the point where piping changes the direction of refrigerant ow from any horizontal run to an upward vertical run.
8
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