KeepRite K40-CU-IM-13 User manual

K40-CU-IM-13
1068155
Installation and Maintenance
Instructions
for
Air-Cooled, Remote and Water-Cooled
Condensing Units
National Refrigeration and Air Conditioning Canada Corp.,
159 Roy Blvd., P.O. Box 2020, Brantford, Ontario, N3T 5Y6
Phone: [phone] Fax: [phone]
Visit our web site at www.keepriterefrigeration.com

2
Table of Contents Pages
General Safety, Inspection & General Warranty Policy 3
Handling, Placement & Installation 4 – 6
Electrical Information & Wiring Diagrams 7 – 14
Refrigerant Piping 15 – 16
Water-Cooled Condensers, Piping & Flow Rates 17 – 18
System Accessories 19
Leak Testing, Evacuation & Dehydration 20
Line Insulation 21
Refrigerant Charging 21 – 23
Compressor Oils 24 – 25
System Start-up Check List 26 – 27
Low Temperature Room Pull-Down 27
Checking Compressor & Evaporator Superheat 28
System Operational Check List 29
System Troubleshooting 30 – 32
Customer Instructions 33
Maintenance Program 33
Service Parts Availability 33
Finished Goods Warranty & Service Log 34
Warranty Activation Certificate 35
Service Parts List Back Cover

3
General Safety
IMPORTANT SAFETY NOTE
Only a qualified refrigeration mechanic who is familiar with refrigeration systems and components, including all
controls should perform the installation and start-up of the system. To avoid potential injury, use care when
working around coil surfaces (if applicable) or sharp edges of metal cabinets. All piping and electrical wiring
should be installed in accordance with all applicable codes, ordinances and local by-laws.
WARNING
Always disconnect and lock off the main power supply on any system that will be worked on to avoid
accidental start up of the equipment.
Inspection
Inspect all equipment before unpacking for visible signs of damage or loss. Check shipping list against material
received to ensure shipment is complete.
IMPORTANT: Remember, you, the consignee, must make any claim necessary against the transportation
company. Shipping damage or missing parts, when discovered at the outset, will prevent later unnecessary and
costly delays. If damage or loss during transport is evident, make claim to carrier, as this will be their
responsibility, not that of the manufacturer.
Should carton be damaged, but damage to equipment is not obvious, a claim should be filed for “concealed
damage” with the carrier.
IMPORTANT: Check the electrical ratings on the unit to make sure they correspond to those ordered and to
electrical power available at the job site. Save all shipping papers, tags, and instruction sheets for reference by
installer and owner.
General Warranty Policy
Please refer to the “Finished Goods Warranty” on page 34.

4
Air Cooled Condensing Unit Minimum Clearance (for Horizontal Air Flow Units)
* Height of
Condensing Unit
Minimum
* No closer than 24" (.62 m)
Walls
*
Width of
Condensin
g
Unit
Minimum
*
Width of
Condensin
g
Unit
Minimum
48" (1.2 m)
Minimum
Air FlowAir Flow
Condensing UnitCondensing Unit
Handling, Placement and Installation
IMPORTANT: When selecting a location for the condensing unit, consideration should be given to some of the
following:
(a) Loading capacity of the floor or roof. Check building codes for weight distribution requirements.
(b) Distance to suitable electrical supply.
(c) Distance to the evaporator.
(d) Adequate air circulation and ventilation.
(e) Close proximity to water source and floor drains (water-cooled units)
(f) Accessibility for maintenance.
(g) Local building codes.
(h) Adjacent buildings relative to noise levels.
(i) Wishes of the end user / owner.
When all of the above points have been considered and a specific location chosen, it is advisable to obtain
written approval of this location from the building and/or condensing unit owner. This may be a means of
avoiding disagreement and expense at a later date.
A fully qualified and properly equipped crew with the necessary tackle and rigging should be engaged to
locate the condensing unit in position. When lifting the unit, spreader bars and chafing gear should be used to
prevent damage.
The unit should be placed on a base, which is level and even. Units should be lagged to sleepers or support
base. Place unit where it will not be subject to damage by traffic or flooding. On critical installations where noise
is liable to be transmitted through the floor structure, vibration isolators should be installed. Isolators should be
installed under mounting base and may be rubber or cork or equal.
DO NOT USE THE SHIPPING SKID AS A PERMANENT BASE.
The condensing unit should be positioned to allow adequate space for performing service work.
Indoor and outdoor air-cooled condensing units should be positioned using the guidelines shown below.

5
SPECIAL NOTE FOR LARGE AIR COOLED CONDENSING UNITS: Vertical flow air cooled condensing units
are large and heavy pieces of mechanical equipment and must be handled as such. A fully qualified and
properly equipped crew with the necessary tackle and rigging should be engaged to locate the condensing unit
into location. The unit can be lifted by means of lifting holes located in the base frame of the unit. Spreader
bars should be used to prevent damage to the sides of the unit. Do not sling directly around the base of unit.
The unit should be placed on a base which is level and even.
Air Cooled Condensing Unit Minimum Clearance (For Vertical Air Flow Units)
Units equipped with spring-mounted compressors have shipping spacers that are designed to hold the
compressor rigidly during transit to prevent possible damage. Before operating the unit, it is necessary to
remove these spacers. To remove the shipping spacers, follow these steps:
(a) Remove the upper nuts / washers.
(b) Discard the shipping spacers.
(c) Install the rubber cone washers (located in the electrical box).
(d) Replace the upper mounting nuts / washers.
(e) Allow 1/16 inch space between the mounting nuts / washers and the compressor foot.
On units equipped with rigid mounted compressors, check the compressor mounting bolts to insure they have
not vibrated loose during shipping.
WALLS OR OBSTRUCTIONS
All sides of the unit must be a minimum of 4 feet
(1.25 m) away from the wall or obstruction.
Overhead obstructions are not permitted. If
enclosed by three walls, the unit must be installed as
indicated for units in a
p
it.
MULTIPLE UNITS
A minimum of 8 feet (2.5 m) is required between
multiple units placed side by side. If placed end to
end, the minimum distance between units is 4 feet
(1.25 m)
UNITS IN PITS:
The top of the unit must be level with, or
above the top of the pit. In addition, a
minimum of 8 feet (2.5 m) is required between
the unit and the pit walls.
LOUVERS / FENCES:
Louvers/fences must have a minimum of 80% free
area and 4 feet (1.25 m) minimum clearance
between the unit and the louver/fence. Height of
louver/fence must not exceed top of unit.
4 ft
(1.25 m)
min.
8 ft
(2.5 m)
min.
8 ft
(2.5 m)
min.
8 ft
(2.5 m)
min.
4 ft
(1.25 m)
min.
4 ft
(1.25 m)
min.

6
Ventilation
If the compressors or condensing units are to be located in machine rooms, adequate ventilation air must be
provided in order to avoid an excessive temperature rise in the room. Air requirements vary with ambient air
temperatures and the refrigeration load, however the following rule of thumb may be used to approximate
ventilating air quantities:
Model Type Air Quantity
Air-cooled condensing units (for horizontal air flow units) 1,000 cfm (472 L/s) per Hp
Air-cooled compressors (with remote condensers) 250 cfm (118 L/s) per Hp
Suction cooled or water-cooled compressors 200 cfm (94 L/s) per Hp
(with remote or water cooled condensers)
All of the above mentioned air quantities are based on relatively short discharge line runs within the machine
rooms. If using long uninsulated discharge line runs are unavoidable in the machine room, additional ventilation
air is required to offset the heat added to the room by the discharge gas.

7
Electrical Information
WARNING
All wiring and connections to the unit must be made in accordance with national as well as local electrical codes
and by-laws.
Electrical wiring should be sized in accordance with the minimum circuit ampacities shown on the unit
nameplate and applicable electrical codes. The unit power connections are approved for copper wire only.
Connect the field power supply through a fused branch circuit disconnect switch. The entering service fuse must
not exceed the maximum overcurrent protection (MOP) value on the unit data plate.
Field connected control circuit wires are terminated directly at the control circuit terminal block in accordance
with the appropriate wiring diagram.
Voltage at the unit terminals must not vary more than the allowable variation during start-up and while under full
load. If the voltage is normal at the supply with the compressor not running and drops considerably when the
switch is closed and the motor is trying to start, there is a high resistance due to undersized wires or faulty
connections. Voltage drop between inoperative and full load must not exceed 3% of line voltage. In addition, the
phase imbalance at the motor terminals should be within 2% on three phase units.
60 Hz Supply 50 Hz Supply
Power Allowable Variation Power Allowable Variation
115-1-60 103-127 V 100-1-50 90-110 V
208/230-1-60 197-254 V 200/220-1-50 190-242 V
208/230-3-60 187-254 V 200/220-3-50 180-242 V
460-3-60 414-506 V 380/400-3-50 342-440 V
575-3-60 518-632 V
All systems should use a liquid line solenoid valve (installed at the evaporator) and should be energized by the
room or fixture thermostat. For systems with a defrost time clock, the liquid line solenoid and thermostat should
be energized by the time clock. Initially set the defrost time clock (model 8145) as follows:
Air defrost evaporators; 3 per day (every 8 hours) with the time termination at 45 minutes.
Electric defrost evaporators; 4 per day (every 6 hours) with time termination set (Fail Safe) at 30 minutes.
Check that the wiring from the defrost termination thermostat is wired to terminal “X” on the clock and terminates
the defrost cycle when the evaporator coil reaches approximately 55 oF. The fan delay thermostat wiring should
also be checked for proper operation. This ensures that all water droplets have been refrozen to the coil before
the evaporator fan starts back up.
Note: The above settings are guidelines only and must be re-adjusted to suit local field conditions and actual
evaporator equipment specifications.
Refer to the evaporator installation manual for further information.
An evaporator airflow interlock is recommended on some installations so that the compressor will pump down
and shut off in the event that the evaporator fan is off for any reason. This is wired into the control circuit in
series with the thermostat and solenoid valve.
Refer to the following wiring diagrams for typical air defrost and electric defrost wiring arrangements.
WARNING
Any deviation or change to the electrical components or wiring as supplied on the original equipment, or
noncompliance with the voltage and phase balance requirements without written authorization will void the
warranty.

8
Electrical Wiring Diagram – Horizontal Air Flow Condensing Units (K-Line)

9
Electrical Wiring Diagram – Horizontal Air Flow Condensing Units (K-Line)

10
Electrical Wiring Diagram – Horizontal Air Flow Condensing Units (K-Line)

11
Electrical Wiring Diagram – Horizontal Air Flow Condensing Units (KE-Line)

12
Electrical Wiring Diagram – Horizontal Air Flow Condensing Units (KE-Line)

13
Electrical Wiring Diagram – Horizontal Air Flow Condensing Units (KE-Line)

14
Electrical Wiring Diagram – Vertical Air Flow Condensing Units

15
Refrigerant Piping
WARNING
All local codes must be observed in the installation of refrigerant piping.
IMPORTANT PIPING NOTE
Appropriate line sizing practices must be used throughout the installation of the refrigeration system. Special
consideration must be taken when the condensing unit is installed above the evaporator. REFRIGERATION
GRADE COPPER TUBING MUST BE USED FOR PIPING SYSTEMS.
Piping practice and line sizing charts as recommended by A.S.H.R.A.E. or other reputable refrigeration
standards must be followed to ensure minimum pressure drop and correct oil return. An inert gas such as dry
nitrogen should be passed through the piping during welding or brazing operations. This reduces or eliminates
oxidation of the copper and formation of scale inside the piping. For specific piping requirements refer to your
local distributor or sales representative.
Correct line sizing is most critical because of the several factors involved:
(a) Minimum pressure drop to ensure efficient compressor performance.
(b) Sufficient gas velocity to maintain proper oil return to the compressor under all load conditions.
(c) Elimination of conditions on multiple evaporators whereby oil may log in an idle evaporator.
Suction lines should be sized on the basis of a maximum total pressure drop equivalent to a 2oF (1.1oC) change
in saturated temperature. At 40oF (4.4oC) suction temperature, this is approximately 3 psig (20.7 kPa) for R-22.
At -20oF (-28.9oC) suction temperature, this is approximately 1.3 psig (9.0 kPa) for R-404A.
Horizontal liquid lines should be sized on a basis of a maximum pressure drop equivalent to a 2oF (1.1oC) drop
in the sub-cooling temperature. If the lines must travel up vertically then adequate sub-cooling must be provided
to overcome the vertical liquid head pressures. A head of two feet of liquid refrigerant is approximately
equivalent to 1 psig (6.9 kPa). Liquid line velocities should not exceed 300 fpm (1.52 m/s). This will prevent
possible liquid hammering when the solenoid valve closes.
PSIG oFPSIG oFPSIG oFPSIG oFPSIG oF
R-134a 4.9 2.0 7.4 2.9 9.8 4.1 12.3 5.2 14.7 6.3
R-22 4.8 1.6 7.3 2.3 9.7 3.1 12.1 3.8 14.5 4.7
R-404A, R-507 4.1 1.1 6.1 1.6 8.2 2.1 10.2 2.7 12.2 3.3
PSIG oFPSIG oFPSIG oFPSIG oF
R-134a 19.7 8.8 24.6 11.0 36.8 17.0 49.1 23.7
R-22 19.4 6.2 24.2 8.0 36.3 12.1 48.4 16.5
R-404A, R-507 16.3 14.1 20.4 5.6 30.6 8.3 40.8 11.8
Based on 110 oF liquid temperature at bottom of riser.
Refrigerant
Liquid Line Rise in Feet
Liquid Line Rise in Feet
Pressure Loss of Liquid Refrigerant in Liquid Line Risers
(Expressed in Pressure Drop PSIG and Subcooling Loss oF)
40' 50' 75' 100'
Refrigerant 30'10' 15' 20' 25'

16
At the temperatures encountered in the condenser, receiver and liquid line a certain amount of oil is always
being circulated with the refrigerant through the system by the compressor. However, at the evaporator
temperature, and with the refrigerant in a vapor state, the oil and refrigerant separate. This oil can only be
returned to the compressor by gravity or by entrainment in the suction gas. Roof installations leave no
alternative but by entrainment for oil return, so suction gas velocity and correct line sizing to maintain this
velocity are imperative. Care must be taken not to oversize the suction line in the desire for maximum
performance.
Gas velocity in vertical suction lines must not be less than 1,000 fpm (5 m/s) and preferably 1,250 to
1,500 fpm (6 to 8 m/s).
Important: A suction trap must be installed at the base of all suction risers of four (4) feet or more in order to
trap oil and allow entrainment in the suction gas.
IMPORTANT PIPING NOTE
If steps of capacity control are supplied on a compressor, provisions must be made for oil return by sizing
suction risers to maintain adequate gas velocities at reduced refrigerant flow.
During the lower capacity running mode (compressor capacity control energized) oil will collect in the elbow or at
U-bend below pipe “B”. This will divert the gas and oil to flow up the smaller pipe “A” at a higher velocity.
IMPORTANT: When welding service valves or any components that may be damaged by heat, manufacturer’s
installation instructions must be adhered to. Wrapping components with a wet cloth will help to prevent damage
from heat.
IMPORTANT: All suction lines outside of the refrigerated space must be insulated.

17
Water-Cooled Condensers
WARNING
All water and drain connections to the unit must be made in accordance with national as well as local plumbing
codes and by-laws.
Cooling water circuits in some shell and tube water-cooled condensers may be either series or parallel as
required by the particular application. The “series” flow is usually for city water where lower entering water
temperatures exist and higher-pressure drops can be tolerated (such as city water supplies). The “parallel”
circuit flows are usually required when the water temperatures enter at 85oF (29.4oC) or higher requiring lower
water pressure drops (such as closed loop cooling tower supplies).
On some condensers, the
water circuiting may be
entirely internal with only an
inlet and outlet water fitting.
The water inlet is always at
the bottom connection.
All water-cooled condensers
require a water regulating
valve that must be installed
upstream of the condenser.
The water-regulating valve is
adjustable and is set to
provide the desired condensing pressure. As the condensing pressure rises, the valve will open and allow more
water to flow. As the condensing pressure lowers the valve will start to close to reduce the amount of water flow
into the condenser. If water supply pressure is excessive, a pressure-reducing valve must be used since the
allowable working pressure of water valves and condensers is normally 150 psig (1136 kPa). Typical
condensing temperatures normally range between 90 to 110 oF. The actual water inlet temperature and water
supply flow capacity available at the site determines the suitable condensing temperature. Lower inlet water
temperatures (below 70 oF) allow the condensing unit to run at a lower condensing temperature without resulting
in a high water flow rate (consumption). Higher water inlet temperatures (above 85 oF) require the condensing
temperature to be higher to avoid excessive water flow rates. Refer to the water flow rate chart to estimate the
flow rate (GPM-US gallon per minute) at given water temperatures and loads. The TD (temperature difference)
is the difference between the condensing temperature and the water inlet temperature.
Example: Given 80 oF inlet water available, +25 oF evaporating temperature application and 1 ton (12,000Btuh)
evaporator load. The results are:
20 oF TD = 100 oF Cond.Temp., series flow is .148 x 12 = 1.78 GPM, parallel flow = .185 x 12 = 2.22 GPM
30 oF TD = 110 oF Cond.Temp., series flow is .103 x 12 = 1.24 GPM, parallel flow = .128 x 12 = 1.54 GPM
Knowing the GPM you can estimate the pressure drop through the condenser (and compressor, if with body
coil). Refer to the Typical Pressure Drop tables and use the appropriate flow to estimate the resulting pressure
drop. If using a condenser that has only ONE water circuit (two connections) use the “parallel” column on the
GPM flow rate chart.
Care should be exercised in locating the condensing unit so that the condenser will never be exposed to
temperatures below freezing.
Excessive water velocities or cavitation on the waterside of the condenser tubes may damage a water-cooled
condenser. In order to prevent operating difficulties, care should be taken to follow the instructions outlined
below:
(a) Water velocities through the condenser should not exceed 7 fps (2.13 m/s). Higher velocities can result
in “impingement corrosion”. In order to maintain water velocities at an acceptable level, parallel circuiting
of the condenser may be necessary when high water flow is required.
(b) If a water-circulating pump is used, it should be installed so that the condenser is fed from the discharge
side of the pump.

18
(c) If the condenser is installed more than 5 ft (1.52 m) higher than the outlet drain point of the condenser, a
vacuum breaker or open vent line should be provided to prevent the outlet line from creating a partial
vacuum condition.
CONSULT THE FACTORY OR LOCAL SALES REPRESENTIVE FOR FURTHER INFORMATION.
90 oF 100 oF 110 oF 90 oF 100 oF 110 oF
45 0.135 0.137 0.142 0.168 0.172 0.175
25 0.144 0.148 0.153 0.179 0.185 0.189
15 0.148 0.153 0.158 0.185 0.192 0.197
-10 0.167 0.173 0.182 0.208 0.217 0.225
-30 0.183 0.190 0.200 0.227 0.237 0.250
90 oF 100 oF 110 oF 90 oF 100 oF 110 oF
45 0.092 0.093 0.095 0.113 0.115 0.118
25 0.097 0.100 0.103 0.121 0.125 0.128
15 0.100 0.103 0.107 0.125 0.130 0.133
-10 0.113 0.118 0.123 0.142 0.147 0.153
-30 0.123 0.128 0.135 0.153 0.160 0.168
Evaporating
Temperature
SERIES PARALLEL
WATER FLOW REQUIREMENTS
(Gallon Per Minute Per 1 MBH Evaporator Load)
LOWER WATER FLOW RATES
30 oTD (Condensing Temperature - Entering Water Temperature)
PARALLEL
Condensing Temperature
Evaporating
Temperature
20 oTD (Condensing Temperature - Entering Water Temperature)
HIGHER WATER FLOW RATES
SERIES
Condensing Temperature
10.6
22
34.2
22.40.3
48.71.2
6 18.6 2.5
22.70.4
49.91.4
6212.9
32.70.4
57.2 1
9212.9
5 2.6 0.35
10 9 1.25
15 18 2.7
10 0.7
15 1.4
25 3.4
10 0.4
20 1.3
40 4.6
30, 35, 40
Typical Pressure Drops (PSIG) Condensers
Consult factory for Data
1
1
3/4
1/2
10
15
20, 25 1 1/2
1 1/4
1 1/4
1,1 1/2 , 2
3, 3 1/2, 4
5, 6
7 1/2, 9
Water
Valve
Size
Flow
(GPM)
Model (HP)
Pressure Drop
Series Parallel
11.7
26.2
3 13.5
10.5
21.3
32.8
45.9
Larger compressor models use fans in place of water cooling coils.
Compressor Coil (smaller models only)
T
yp
ical Pressure Dro
p
s
(
PSIG
)
Compressor
Model Family Flow (GPM) Pressure Drop
KW
EW / 3W

19
System Accessories
In order to ensure trouble free operation of the refrigeration system it is important that the following system
accessories be reviewed and installed.
(a) A moisture indicating LIQUID SIGHT GLASS should be installed in the liquid line between the
receiver and as close as possible to the expansion valve on the evaporator. If it is mounted on the
condensing unit, it will be mounted downstream of the receiver outlet service valve and immediately
after the liquid line drier. It will change color if there is moisture present in the system. It also allows the
contractor to detect a shortage of refrigerant or flash gas in the liquid line. Bubbles are not normally
visible in the sight glass of a properly charged system, however it is normal to see bubbles appear in the
sight glass for a few minutes when the compressor starts. Bubbles in a sight glass installed on the
condensing unit must never be used as the final indicator for shortage of refrigerant in the
system.
(b) A LIQUID LINE FILTER DRIER (sealed or replaceable core) should be installed in the system to
remove foreign matter and moisture that may have entered the system during installation. Liquid line
driers should be installed downstream of the receiver outlet valve and upstream of the liquid line
solenoid valve (if supplied). Liquid line driers may or may not have access valves, depending on the
size and application. They should be replaced whenever there is excessive pressure drop across the
filter, or when the system becomes contaminated due to system leaks, compressor burn-outs, acid
formation, or moisture accumulation as indicated by the moisture indicating sight glass. Refer to the
specific manufacturer’s recommendation for servicing.
(c) A DISCHARGE MUFFLER may be used to help minimize the noise created in the discharge line of the
compressor. This noise my be the result of variations in piping configuration, the pattern of the gas flow,
line sizes, operating pressures or compressor and unit mounting. A particular combination of gas flow
and piping will result in a resonant frequency, which may amplify the sound and vibration to an
undesirable level. Gas pulsations from the compressor discharge may also be amplified in a similar
manner.
(d) A DISCHARGE OIL SEPARATOR may be used with flooded systems, low temperature systems and
systems with long runs of piping or other factors that tend to cause oil return problems. They help
maintain oil volume levels in the compressor oil sump.
(e) A LIQUID LINE SOLENOID VALVE must be installed at the evaporator. Installing a solenoid valve will
allow all of the refrigerant to be pumped out of the low side (evaporator and suction line) when the
thermostat has been satisfied. This reduces the risk of refrigerant migrating or flooding back to the
compressor. Locating the solenoid at the evaporator (instead of the condensing unit) will minimize the
pump-down time and refrigerant capacity required by the receiver.
(f) A SUCTION LINE FILTER (sealed or replaceable core) when used are always installed upstream of the
compressor suction service valve and any accumulators or other options that may be installed. Suction
filters are equipped with “Schrader” type access valves that allow plugged filters and elements to be
identified quickly when the pressure drops get too high. Refer to the specific manufacturer’s
recommendation for servicing.
(g) Units equipped with spring-mounted compressors should have VIBRATION ELIMINATORS in both the
suction and discharge lines. They minimize noise transmission and provide flexibility if it is ever
necessary to remove a compressor. Vibration eliminators should be installed at ninety degrees to the
vibration for best results and whenever possible, in a horizontal position, parallel to the compressor
crankshaft. Suction vibration eliminators MUST be insulated on low temperature systems to prevent
refreezing of condensate, causing expansion damage to the bellows inside the eliminator. This
expansion can eventually fatigue the copper bellows causing rupture and loss of refrigerant.
(h) A SUCTION LINE ACCUMULATOR is used to prevent liquid refrigerant from reaching the compressor.
Liquid flood back can occur for various reasons such as a malfunctioning expansion valve, refrigerant
overcharge, hot gas defrost cycle or extremely low load on the evaporator. An accumulator should be
used if frost or dirt collect on the evaporator coil(s). This can reduce the heat transfer. Some suction line
accumulators are equipped with a built in suction to liquid line heat exchangers. All hot gas defrost
systems must use an accumulator.
(i) A SUCTION TO LIQUID HEAT EXCHANGER should be used if a system requires long liquid lines from
the receiver to the evaporator or if the liquid has to rise vertically upward any distance. It can help
prevent excessive frosting on the compressor body and increase superheat in the suction line reducing
the possibility of liquid refrigerant from returning to the compressor.
(j) A PHASE / VOLTAGE MONITOR protects the system against phase loss (single phasing), phase
reversal (improper sequence), high voltage and low voltage (brownouts).

20
Leak Testing
IMPORTANT: All system piping, including the condensing unit and accessories should be thoroughly tested for
leaks prior to start up and charging. The system should be initially pressurized to a maximum of 150 psig (1136
kPa) with dry nitrogen to ensure that the system is free of major leaks. With the system free of major leaks, a
more detailed leak check should be performed. Discharge the initial dry nitrogen charge and add enough
refrigerant to raise the system pressure up to 10 psig (170 kPa) (tracer amount). Add dry nitrogen to increase
the system pressure to a maximum of 150 psig (1136 kPa). It is recommended that an electronic leak detector
be used when checking for leaks because of its greater sensitivity to small leaks. As a further check it is
recommended that this pressure be held for a minimum of 12 hours and then rechecked. The system must be
leak free for satisfactory operation.
WARNING
HFC-134a has been shown to be combustible at pressures as low as 5.5 psig (140 kPa) at 350 o F (176.7 o C)
when mixed with air at concentrations more than 60% air by volume. At lower temperature, higher pressures
are required to support combustion. Therefore, air should never be mixed with HFC-134a for leak detection.
IMPORTANT ENVIRONMENTAL NOTE
When conventional leak detection methods are employed using HCFC or CFC tracer gas, all of the tracer gas
must be reclaimed and disposed of in a proper manner.
Evacuation and Dehydration
When the system is completely free of refrigerant leaks, an evacuation of the entire system should be completed
by using a “high vacuum” pump. This evacuation, if completed correctly, will ensure long life for the system as
well as elimination of moisture and non-condensable gas problems. Moisture problems causing compressor
failure will void warranty. Follow the recommended procedure carefully.
CAUTION
Do not use the refrigeration compressor to evacuate the system. Never start the compressor or perform a
megger insulation test while the system is in a vacuum.
Dehydration Procedure
Use only a “high vacuum” pump capable of drawing a vacuum of 100 microns. Change the vacuum pump oil
frequently. Gauges or vacuum measuring instruments should be suitable to measure conditions at any stage of
the process in order to give the operator indications of progress. For specific recommendations, refer to the
vacuum pump supplier for these instruments.
Copper jumper lines should be used to interconnect both high and low-pressure sides of the system. These
lines should be at least 3/8” O.D. in order to handle the light density vapor at high vacuum obtained at
completion of operation. Lines smaller than 3/8” O.D. will slow down the process considerably as well as making
final system vacuum questionable. The entire system temperature should be over 60 oF (16 oC) for evacuation to
be effective. If the temperature is less than 60 o
F (16 o C) the final vacuum should be 50 microns. Double
evacuation with a “sweeping “ of dry nitrogen is recommended. First evacuation should be to at least 750-micron
depth. When this point is reached, break the vacuum with refrigerant or dry nitrogen to melt any moisture, which
may have frozen during the first vacuum stage.
IMPORTANT ENVIRONMENTAL NOTE
When conventional leak detection methods are employed using HCFC or CFC tracer gas, all of the tracer gas
must be reclaimed and disposed of in the proper manner.
Reclaim any tracer gas from the system and re-evacuate to a final vacuum of at least 100 microns at a minimum
60 o
F (16 o C) system temperature. With this degree of evacuation, all moisture and non-condensables will be
removed from the entire system.