Bohn H-IM-65B Installation Manual
Air Cooled
Condenser
Installation
Bulletin No. H-IM-65B December 1999 Part Number 90800701
Replaces H-IM-65A, August 1996
Angle Leg Models
Channel Legs Models
Air-Cooled
Condensers
21 - 212 Tons
Installation and
Maintenance Data
Table of Contents
Inspection
System Warranty
Installation
Unit Location
Sound Vibration . . . . . . . . . . . . . . . . . . . . . . . . 2
Rigging Instructions . . . . . . . . . . . . . . . . . . . . . 3
Space and Location Requirements . . . . . . . . . 4
Typical Arrangements
Installation, Refrigerant Piping . . . . . . . . . . . . . 5
Line Sizing
Discharge Lines
Electrical Wiring . . . . . . . . . . . . . . . . . . . . . . . . 6
Typical Wiring Diagrams . . . . . . . . . .. . . . . . . 7-8
Start-Up
Discharge Gas Pulsation
Operation
Winter Operation Head Pressure Control
Fan Cycling . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Fan Cycling Head Pressure Controls
Flooding Head Pressure Controls
Refrigerant Charge . . . . . . . . . . . . . . . . . . . . . . 10
Minimum Ambient for Fan Cycling
Mechanical Fan Cycling Thermostat Settings. . 11
Electronic Fan Cycling Thermostat Settings
Pressure Chart . . . . . . . . . . . . . . . . . . . . . . . . . 12
Additional Refrigerant Charges
Maintenance
Cleaning Instructions . . . . . . . . . . . . . . . . . . . . 13
In-Warranty Return Material Procedure
Replacement Parts . . . . . . . .. . . . . . . . . . . . . 14
Installation Check List . . . . . . . . . . . . . . . . . 15
1
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 for.
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 units shipping base until it has been moved to the
nal location.
System Warranty
This equipment is designed to operate properly and produce
rated capacity when installed in accordance with accepted
industry standards. Failure to meet the following conditions
may result in voiding of the system warranty:
1. System piping must be installed following industry
standards for good piping practices.
2. Inert gas must be charged into piping during
welding.
3. System must be thoroughly leak checked and
evacuated before initial charging. High vacuum
gauge capable of reading microns is mandatory.
Dial indicating pressure gauges are not acceptable.
4. Power supply to system must meet the
following conditions:
a. Voltage for 208/230 motors not less than
195 volts or more than 253 volts.
b. All other voltages must not exceed +/- 10%
of nameplate ratings.
c. Phase imbalance not to exceed 2%.
5. All controls and safety switch circuits properly
connected per wiring diagram.
6. Factory installed wiring must not be changed without
written factory approval.
Installation
Note: Installation and maintenance to be performed
onlybyqualiedpersonnelwhoarefamiliarwith
local codes and regulations, and experienced
withthistypeofequipment.
Caution: Sharp edges and coil surfaces are a
potential injury hazard.
Avoidcontactwiththem.
Unit Location
Units are designed for outdoor application and may be
mounted on a roof or concrete slab (ground level installation).
Roof mounted units should be installed level on steel
channels or an I-beam frame to support the unit above the
roof. Use of vibration pads or isolators is recommended. The
roof must be strong enough to support the weight of the unit.
Concrete slabs used for unit mounting should be installed
level and be properly supported to prevent settling. A onepiece concrete slab with footings extending below the frost
line is recommended.
The condenser should be located far enough away from any
wall or other obstruction to provide sufcient clearance for air
entrance. Do not attach ductwork to the coil inlet or fan outlet.
Care should be taken to avoid air recirculation conditions that
can be caused by sight screening, walls, etc. Also keep unit
fan discharge away from any building air intakes. See page 4
for space and location requirements.
Sound Vibration
Units should be installed away from occupied spaces and
above or outside of utility areas, corridors and auxiliary
spaces to reduce the transmission of sound and vibration to
occupied spaces. The refrigerant piping should be exible
enough to prevent the transmission of noise and vibration
from the unit into the building. If the refrigerant lines are to
be suspended from the structure of the building, isolation
hangers should be
used to prevent the transmission of vibration. Where piping
passes through a wall, it is advisable to pack berglass and
sealing compound around the lines to minimize vibration and
retain exibility in the lines.
The unit needs to be secured in its nal location. Holes are
provided in the base runner for this purpose.
Warning: This equipment may contain a substance
whichharmsthepublichealthand
environment by destroying ozone in the
upper atmosphere. Venting of certain
refrigerants to the atmosphere is illegal.
Refrigerant recovery devices must be used
wheninstallingorservicingthisproduct.
Consult your local codes for requirements
in your location.
Warning: There may be more than one source of
electrical current in this unit. Do not
servicebeforedisconnectingallpower
supplies.
2
© 2004, Heatcraft Refrigeration Products LLC
Drawing1.RiggingInstructions
3
Space and Location Requirements
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 condenser
area. Where this essential requirement is not adhered to,
it will result in higher head pressures, which cause poor
operation and possible eventual failure of equipment. Units
must not be located in the vicinity of steam, hot air or fume
exhausts.
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.
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.
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.
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.
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”.
* “W” = Total width of the condenser.
4
Typical Arrangements
Notes:
Figure 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 sufciently at
reduced load conditions; however, when operating at full load,
the line would be greatly undersized, and thereby create an
excessive refrigerant pressure drop. This condition can be
overcome in one of two following ways:
1.The discharge line may be properly sized for the desired
pressure drop at full load conditions and an oil separator
installed at the bottom of the trap in the discharge line
from the compressor.
2. A double riser discharge line may be used as shown in
Figure 2. Line “A” should be sized to carry the oil at mini mum load conditions and the line “B” should be sized so
that at the full load conditions both lines would have suf cient ow velocity to carry the oil to the condenser.
For more complete information, refer to the ASHRAE
Handbook on Systems.
Figure 1
1. All oil traps are to be as short in radius as
possible. Common practice is to fabricate the
trap using three 90 degrees ells.
2. Pressure relief valves are recommended at the
condenser for protection of the coil.
3. A drain line check valve is recommended for
applications where the condenser may be at a
lower temperature than the receiver.
Installation, Refrigerant Piping
Install piping according to standard accepted
refrigeration practice. The following recommendations
should be adhered to:
1. See Tables 1 and 2 for discharge and liquid
drain line sizes for remote condenser
connections.
2. Use only refrigeration grade copper tubing.
3. Soft solder joints are not acceptable.
4. Put dry nitrogen through lines while brazing.
5. Do not leave dehydrated piping or components
open to the atmosphere any longer than is
absolutely necessary.
Figure 2
5
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