Heatcraft Refrigeration Products Condensing Units H-IM-CU Manual De Usuario

Due to the smaller molecule size of HFC’s, they will tend to leak more readily 

than CFC’s. Consequently, it is of the utmost importance that proper system 

evacuation and leak detection procedures be employed.
Copeland recommends a minimum evacuation to 500 microns. In addition, 

a vacuum decay test is strongly recommended to assure there is not a 

large pressure differential between the system and vacuum pump. Good 

evacuation processes include frequent vacuum pump oil changes and large 

diameter, short hose connections to both high and low sides of the system 

preferably using bronze braided hose.
Leak detection can be carried out in the conventional manner.  

If HCFC or CFC tracer gas is used, care must be taken to completely remove 

all traces of the gas prior to introducing HFC’s.
Electronic leak detectors are now available that will sense HFC’s.  This is 

considered preferable since it removes the possibility of chlorine remaining 

in the system after leak testing with HCFC’s and/or CFC’s. There is a view that 

even small quantities of chlorine may act as a catalyst encouraging copper 

plating and/or corrosion and should therefore be avoided.

HFC-134a has been shown to be combustible at pressure as low as 5.5 

psig (at 350˚F) 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.

Within the last several years, manufacturers have developed fluorescent dye 

leak detection systems for use with refrigerants.  These dyes mix with the 

lubricant and, when exposed to an ultraviolet light “fluoresce,” indicates the 

location of leaks. Copeland has tested and approved the Rigid “System Safe” 

dye and found it to be compatible with the compressor materials in systems.

After all lines are connected, the entire system must be leak tested. The 

complete system should be pressurized to not more than 150 psig with 

refrigerant and dry nitrogen (or dry CO

2

). The use of an electronic type leak 

detector is highly recommended 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. For a satisfactory installation, the 

system must be leak tight.  

After the final leak test, refrigerant lines exposed to high ambient conditions 

should be insulated to reduce heat pickup and prevent the formation of 

flash gas in the liquid lines. Suction lines must always be insulated with 3/4" 

wall Armstrong “Armaflex” or equal. When required, Liquid lines should be 

insulated with 1/2 inch wall insulation or better. The insulation located in 

outdoor environments should be protected from UV exposure to prevent 

deterioration of insulating value.

Do not use the refrigeration compressor to evacuate the system.  Do 

not start the compressor while it is in a vacuum. 

A good, deep vacuum pump should be connected to both the low and high 

side evacuation valves with copper tube or high vacuum hoses (1/4" ID 

minimum).  If the compressor has service valves, they should remain closed. 

A deep vacuum gauge capable of registering pressure in microns should be 

attached to the system for pressure readings. 
A shut off valve between the gauge connection and vacuum pump should 

be provided to allow the system pressure to be checked after evacuation. Do 

not turn off vacuum pump when connected to an evacuated system before 

closing shut off valve.  
The vacuum pump should be operated until a pressure of 1,500 microns 

absolute pressure is reached — at which time the vacuum should be broken 

with the refrigerant to be used in the system through a drier until the system 

pressure rises above “0” psig.  

Refrigerant used during evacuation cannot be vented.  Reclaim all used 

refrigerant. EPA regulations are constantly being updated.  Ensure your 

procedure follows correct regulations.

Repeat this operation a second time.  
Open the compressor service valves and evacuate the entire system to 500 

microns absolute pressure.  Raise the pressure to 2 psig with the refrigerant 

and remove the vacuum pump.

Install a liquid line drier in the refrigerant supply line between the  

 

 

service gauge and the liquid service port of the receiver.  This  

 

 

extra drier will insure that all refrigerant supplied to the  

 

 

 

system is clean and dry.
When initially charging a system that is in a vacuum, liquid    

 

 

refrigerant can be added directly into the receiver tank.
Check equipment catalog for refrigerant capacity. System    

 

 

refrigerant capacity is 90% of receiver capacity. Do not add more  

 

 

refrigerant than the data tag indicates, unless the line run exceeds  

 

 

25ft. Then, add additional refrigerant as per the chart on page 30.  

 

 

Weigh the refrigerant drum before charging so an accurate record  

 

 

can be kept of the weight of refrigerant put in the system.
Start the system and finish charging until the sight glass indicates  

 

 

a full charge and the proper amount has been weighed in. If the  

 

 

refrigerant must be added to the system through the  

 

 

 

suction side of the compressor, charge in vapor form only. Liquid  

 

 

charging must be done in the high side only or with  

 

 

 

liquid metering devices to protect the compressor.

If you are charging the system by using a clear sight glass as an indication of 

proper charge the following must be considered.
Check the condensing temperature. It must be above 105˚F. If not, it will be 

necessary to reduce the amount of air going through the condenser from 

fans still running. Simply reduce the effective condenser face area to raise the 

discharge pressure above the equivalent 105˚F condensing temperature and 

then proceed to charge to clear the sightglass. Adjust evaporator superheat 

at this time. Return to full condenser face area and allow the system to 

balance.

All wiring must be done in accordance with applicable codes and local 

ordinances.

The field wiring should enter the areas as provided on the unit.  The wiring 

diagram for each unit is located on the inside of the electrical panel door.  

All field wiring should be done in a professional manner and in accordance 

with all governing codes.  Before operating unit, double check all wiring 

connections, including the factory terminals. Factory connections can vibrate 

loose during shipment.

The serial data tag on the unit is marked with the electrical characteristic  

 

for wiring the unit.
Consult the wiring diagram in the unit cooler and in the condensing unit  

 

for proper connections.  
Wire type should be of copper conductor only and of the proper  

 

 

size to handle the connected load.
The unit must be grounded.
For multiple evaporator systems, the defrost termination controls  

 

 

should be wired in series. Follow the wiring diagrams for multiple  

 

 

evaporator systems carefully. This will assure complete defrost of  

 

 

all evaporators in the system.
Multiple evaporator systems should operate off of one thermostat.
If a remote defrost timer is to be used, the timer should be located  

 

 

outside the refrigerated space.
For air cooled condensers, due to multiple low amp motors, we  

 

 

recommend using time delay fuse protection instead  

 

 

 

of circuit breakers.

1.

2.

3.

4.

1.

2.

3.

4.
5.

6.
7.

8.