Bohn BNH-D14-A123 Installation Manual
Air-Cooled Condenser
Installation & Operation
Bulletin No. H-IM-90 August 2008 Part Number 25007301
Replaces H-IM-90, March 2006
Table of Contents
Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Air-Cooled
Condensers
Installation and
Operation Guide
Applicable for Bohn, Larkin,
Climate Control, and Chandler brands
System Warranty
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Unit Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Sound Vibration
Rigging Instructions
Space and Location Requirements
Typical Arrangements
Installation, Refrigerant Piping
Line Sizing
Discharge Lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Electrical Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Typical Wiring Diagram
Start-Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Discharge Gas Pulsation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Winter Operation Head Pressure Control . . . . . . . . . . . . . . . . .
Fan Cycling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fan Cycling Head Pressure Controls
Flooding Head Pressure Controls . . . . . . . . . . . . . . . . . . . . . . . .
Refrigerant Charge
Minimum Ambient for Fan Cycling
Mechanical Fan Cycling Thermostat Settings
Electronic Fan Cycling Thermostat Settings
Pressure Chart
Refrigerant Charge for Fan Cycling plus Flooded Condenser
Flooded Charge Temperature Dierence Factor
Additional Refrigerant Charges
Model Cross Reference
Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Cleaning Instructions
In-Warranty Return Material Procedure
InterLink Parts List
E Series Motors with Integrated Variable Speed
Speed Adjustment Characteristics
External Control Signal
Proportional Pressure Control
Head Pressure Setpoint
Minimum Output
Throttling Range
Integration Constant
Reverse Acting or Direct Acting Mode
Master/Slave Conguration
Protective Features
Phase Failure
EC Motor Wiring
Typical 1 x 4 EC Motor Wiring Diagram
Typical EC Condenser Wiring with Ext. Signal
Typical EC Condenser Wiring with Proportional
Pressure Control
Installation Check List
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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
only by qualied personnel who are familiar with
local codes and regulations, and experienced
with this type of equipment.
Caution: Sharp edges and coil surfaces are a potential injury
hazard. Avoid contact with them.
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 one-piece 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 sucient 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
which harms the public health and
environment by destroying ozone in the
upper atmosphere. Venting of certain
refrigerants to the atmosphere is illegal.
Refrigerant recovery devices must be used
when installing or servicing this product.
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
service before disconnecting all power
supplies.
© 2008, Heatcraft Refrigeration Products LLC
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Drawing 1. Rigging Instructions
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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.
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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 suciently 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 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.
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
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Discharge Lines
The proper design of discharge lines involves two objectives:
1. To minimize refrigerant pressure drop, since high
pressure losses cause increased compressor
horsepower per ton of refrigerant.
2. To maintain suciently high gas velocity to carry oil
through to the condenser coil and receiver at all loading
conditions.
Table 1. Tons of Refrigeration
Line Size
Type L Copper
OD
R-22 Sat. Suction Temp (°F) R-404A/R-507 Sat. Suction Temp (°F)
-40 0 40 -40 0 40 R-22 R-404A
1/2 0.75 0.8 0.85 0.56 0.63 0.7 2.3 1.5
5/8 1.4 1.5 1.6 1.0 1.2 1.3 3.7 2.3
7/8 3.7 4.0 4.2 2.7 3.1 3.4 7.8 4.9
1-1/8 7.5 8.0 8.5 5.5 6.3 7.0 13.2 8.3
1-3/8 13.1 14.0 14.8 9.6 10.9 12.1 20.2 12.6
1-5/8 20.7 22.0 23.4 15.2 17.2 19.1 28.5 17.9
2-1/8 42.8 45.7 48.5 31.4 35.6 39.5 49.6 31.1
2-5/8 75.4 80.4 85.4 55.3 62.8 69.5 76.5 48.0
3-1/8 120.2 128.2 136.2 87.9 99.8 110.5 109.2 68.4
3-5/8 178.4 190.3 202.1 130.5 148.1 164.0 147.8 92.6
4-1/8 251.1 267.8 284.4 183.7 208.4 230.9 192.1 120.3
Source: ASHRAE Refrigeration Handbook:
1. Line sizes based on pressure drop equivalent to 1°F per 100 equivalent feet.
2. Values in Table are based on 105°F condensing temperature. Multiply Table capacities by the factors in Table 2 for other condensing temperatures.
3. If subcooling is substantial or the line is short, a smaller line size may be used. Applications with very little subcooling or very long lines may require larger sizes
Discharge Line Drain Line
Velocity 100 FPM Refrigerant
Table 2. Condensing Temperature Correction Factor
Condensing
Temperature
90 0.88 0.91 0.922 0.924 0.872 0.889 0.882
100 0.95 0.97 0.974 0.975 0.957 0.963 0.961
110 1.04 1.02 1.009 1.005 1.036 1.032 1.026
120 1.10 1.08 1.026 1.014 1.009 1.096 1.078
130 1.18 1.16 1.043 1.024 1.182 1.160 1.156
R-22 R-502 R-404A R-507 R-407C R-410A R-134A
Discharge Line
Electrical Wiring
The electrical installation should be in accordance with National
Electrical Code, local codes and regulations. Proper overcurrent
protection should be provided for the fan motors.
All standard motors have internal inherent overload protectors.
Therefore, contactors can be used instead of starters requiring
thermal protectors, eliminating the problem of furnishing the
proper heating elements.
All air-cooled condensers are furnished with either single-phase
or three-phase fan motors which are identied by the unit
dataplate.
Electrical leads from each motor terminate at the unit junction
box. Field connections must be made from these leads in
accordance with local, state and national codes.
Three-phase motors must be connected to three-phase power of
voltage to agree with motor and unit dataplate.
The motors are wired into a common junction box. Where
fan cycling is furnished and factory installed, the motors are
completely wired through the control and to the contactors. The
motors must be checked for proper rotation. Be sure to check that
motor voltage and control connection agree with electric services
furnished.
WARNING: There may be more than one source of electrical current in this unit. Do not service before disconnecting all power supplies.
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