Heatcraft Refrigeration Products Condensing Units H-IM-CU ユーザーズマニュアル

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.

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 off at disconnect switch.
Swap any two of the three power input wires.
Turn power on.  Indicator light should glow and compressor  

 

should start.
Observe motors for correct rotation. 

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 filter-driers on  

 

  

condensing units open to the atmosphere any longer than is  

 

 

absolutely necessary.
Use only refrigeration grade copper tubing, properly sealed  

 

 

against contamination.   
Suction lines should slope 1/4" per 10 feet towards  

 

the compressor.

1.
2.
3.

4.

a)

b)

c)

Suitable P-type oil traps should be located at the base of each    

 

suction riser to enhance oil return to the compressor.
For desired method of superheat measurement, a pressure tap    

 

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

oxidation inside the tubing. Dry nitrogen is preferred.
Use only a suitable silver solder alloy on suction and liquid lines.
Limit the soldering paste or flux to the minimum required to  

 

 

prevent contamination of the solder joint internally. Flux only the  

 

male portion of the connection, never the female.  After brazing,   

 

remove excess flux.
See Table 6 for discharge and liquid drain line sizes for remote    

 

condenser connections.
If isolation valves are installed at the evaporator, full port ball  

 

 

valves should be used.

Normally, any straight run of tubing must be supported in at least two    

 

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    

 

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  

 

 

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  

 

stress concentration and are subject to breakage at these points.
Thoroughly inspect all piping after the equipment is in operation and    

 

add supports wherever line vibration is significantly greater than most   

 

of the other piping. Extra supports are relatively inexpensive as  

 

 

compared to refrigerant loss.

d)

e)

g)
h)

i)

j)

1.

2.

3.

4.

5.

Slope 1/4" 

per 10 ft. 

toward 

compressor

Sized for

Minimum 

Load

Sized  

for Full

Load

Sized for

Minimum 

Load

Sized  

for Full

Load

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.

A suction line trap must be installed at the point where piping changes the direction of refrigerant flow from any horizontal run to an upward vertical run.