Background Image
Previous Page  42 / 124 Next Page
Show Menu
Previous Page 42 / 124 Next Page
Page Background

Visit our website:



Selection Method

To determine DCFM for Oil Separator sizing the following parameters are



Evaporating Temperature


Condensing Temperature


Cooling Capacity (in Tons)


Refrigerant Type

Use the following method to determine the DCFM needed for Oil Separator


1. Find the corresponding DCFM/Ton factor by locating the appropriate

evaporating and condensing temperatures and refrigerant type on

the DCFM/Ton Factor table.

2. Multiply the DCFM/Ton factor by the Cooling Capacity to determine

the resulting DCFM for Separator sizing.

3. Use the associated Oil Separator DCFM Capacity table in each Oil

Separator section to determine Oil Separator models where the

calculated system DCFM falls between the minimum and maximum

DCFM rating.

4. From the selected models, choose appropriate Oil Separator by

taking into account connection size and serviceable/non-serviceable


If the refrigerant type required is not listed or if there are any questions about

proper separator sizing please contact Technical Support at 1-800-627-5148.

Determining Oil Separator Gas DCFM

Correct Oil Separator sizing is essential for proper oil separation and minimal

pressure drop across the separator. The following example will demonstrate

how to select an Oil Separator based on a discharge cubic feet per minute

(DCFM) value that has been calculated using four primary system


It is important to determine the DCFM value of the hot gas flow approaching

the Oil Separator. The DCFM values entering the Oil Separator are shown as

a minimum and maximum allowed. The minimum DCFM rating is based on

the minimum allowed gas velocity for oil separation to occur, while the

maximum DCFM rating is when a 0.75-1.0 psi pressure drop will develop

across the Oil Separator.

Selection Example

The following system parameters will be used for the sizing example:


Evaporating Temperature = -40°F


Condensing Temperature = 105°F


Cooling Capacity (in Tons) = 20 Tons


Refrigerant Type = R-404A


Line Size = 1-5/8”


Oil Separator type desired = Serviceable Helical Oil Separator

1. The DCFM/Ton table shows a DCFM/Ton factor of 0.790 for the

chosen system parameters

2. System DCFM = DCFM/Ton factor x Cooling capacity

0.790 x 20 = 15.8 DCFM

3. The Helical Oil Separator DCFM Capacity table lists the following

separators that meet the DCFM requirements:

S-5190, S-5192, S-5194, S-5290, S-5292, and S-5294

4. Based on the line size and desired type, the S-5292 would be the

best choice*.

*Selecting a Helical Oil Separator with a connection size smaller than the line

size will help keep the velocity high needed for separation, if the system

experiences frequent unloading, but may lead to a slightly higher pressure

drop across the Oil Separator at full capacity. Selecting a Helical Oil

Separator with a connection size larger than the line size is not

recommended due to the loss of velocity as the discharge gas enters the Oil

Separator. Please contact Technical Support at 1-800-627-5148 for

assistance or recommendations when selecting Oil Separators.