Heatcraft Refrigeration Products H-IM-CU Manuale Utente

The indoor compressor units are designed to be used with a remote 

condenser.  The water cooled units are similar, except that they have an 

integral water cooled condenser. Inlet and outlet water connections are to 

be made in the field.  On units having a compressor water jacket, incoming 

water shall be routed through the jacket prior to entering the condenser.  For 

cleaning purposes, condenser end plates can be removed to give access to 

the water tubes.  Cleaning is accomplished by a simple spiral tool powered 

by an ordinary electric drill.  During installation, allow space for cleaning the 

condenser.  Commercial equipment of this type is intended for installation 

by qualified refrigeration mechanics.   

Diagram 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 sufficiently at reduced 

load conditions; however, when operating at full load, the line would be 

greatly undersized, and thereby creating an excessive refrigerant pressure 

drop.  This condition can be overcome in one of two of the following ways:

 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.

1.

In the refrigeration industry “City” and “Tower” are designations of 

temperature and flow conditions, not applications.  The term “City” refers 

to operating conditions where incoming water is 75˚F, and condensing 

temperature is 105˚F. “Tower” refers to a higher temperature relationship 

which is normally 85˚F, incoming water and 105˚F condensing temperature.
Water circuits in some condenser models provide a center, or Tower, outlet 

connection to allow divided inlet water flow. This extra water port reduces 

water velocity, water pressure drop, and condenser wear in applications such 

as cooling towers where higher inlet temperatures and water flows occur.

For City water (open system) high pressure applications, the Tower 

connections is plugged.

For Tower usage and low pressure applications, both normal water 

connections will be used as inlets and the tower connection as an outlet.

A double riser discharge line may be used as shown in  

 

 

 

Diagram 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 sufficient flow velocity  

 

 

to carry the oil to the condenser.

Using this control on the water cooled condensing units, the head pressure 

can be maintained by adjusting the flow of water through the condenser 

section.  This type control is most often located on the water entering side of 

the condenser and is regulated by the refrigerant condensing pressure.

Diagrams 1 and 2 below show typical subcooler piping.  Diagram 1 is the 

preferred connection with receiver as it provides maximum subcooling.  

Diagram 2 may be used if the receiver is located far from the condenser.
Notes:

All oil traps are to be as short in radius as possible. Common practice is   

 

to fabricate the trap using three 90 degree ells.
Pressure relief valves are recommended at the condenser for protection  

 

of the coil. 
A pressure valve at the high point in the discharge line is recommended  

 

to aid in removing non-condensables.
The placement of a subcooler should be that it does not interfere with    

 

normal airflow of the condenser. Increased static of the unit could cause  

 

a decrease in system capacity and fan motor damage.

2.

1.

2.

3.

4.