Gardner Denver INTEGRA EFD99E, Operating And Service Manual

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COMPRESSOR OIL COOLER

 -  The cooler fan is mounted on the compressor motor shaft; air is 

exhausted through the oil cooler and away from the unit.  Do not obstruct air flow to and from the oil 
cooler.  Allow a minimum of two (2) feet (.6M) clearance around the cooler.  Keep both faces of the cooler 
core clean for efficient cooling of compressor oil. 

THERMAL CONTROL (THERMOSTATIC MIXING) VALVE

 (Figure 5-1 page 35) - is installed in the 

system.  This valve is used to control the temperature of the oil.  On start-up with unit cold, the element is 
open to bypass, allowing oil to pass directly from the reservoir to the compressor during warm-up.  As oil 
warms, the element gradually closes to the bypass allowing more of the oil from the cooler to mix with oil 
from the bypass.  

After the unit is warmed up, the mixing valve maintains oil injection temperature into the compressor at a 
minimum of 150

°

 F (66

°

 C).  This system provides proper compressor warm-up and prevents moisture 

contamination of the oil. 

To check the element, heat it in oil - it should be fully extended at 150

°

 F (66

°

 C).  If the unit shuts down 

due to high air discharge temperature, the cause may be that the element is stuck open to the bypass.  
When flushing the oil system, remove the mixing valve and clean all parts thoroughly. 

OIL RESERVOIR

 - The oil reservoir-separator combines multiple functions into one vessel.  The lower 

half is the oil reservoir, providing oil storage capacity for the system and the top portion, a primary oil 
separation means.  The reservoir also provides limited air storage for control and gauge actuation. 

COMPRESSOR AIR/OIL SEPARATOR

 - Located in a separate housing, consists of a renewable 

cartridge-type separator element and provides the final removal of oil from the air stream.  

Oil impinging on the inside of the separator element drains directly back into the oil reservoir by gravity.  
Oil collected outside the element is returned through tubing to the compressor cylinder. 

Oil carryover through the service lines may be caused by a faulty oil separator, overfilling of the oil 
reservoir, oil that foams, oil return line malfunction, or water condensate in the oil.  If oil carryover occurs, 
inspect the separator only after it is determined that the oil level is not too high, the oil is not foaming 
excessively, the oil return tube from the bottom of the separator to the compressor cylinder is not clogged 
or pinched off, the check valve in the oil return is functioning properly, and there is not water or an 
oil/water emulsion in the oil. 

Oil carryover malfunctions of the oil separator are usually due to using elements too long, heavy dirt or 
varnish deposits caused by inadequate air filter service, use of improper oil, or using oil too long for 
existing conditions.  Excessive tilt angle of the unit will also hamper separation and cause oil carryover. 

Oil separator element life cannot be predicted; it will vary greatly depending on the conditions of 
operation, the quality of the oil used and the maintenance of the oil and air filters.  The condition of the 
separator can be determined by pressure differential or by inspection. 

Pressure Differential Gauging – 

The “CHANGE SEPARATOR” advisory will flash when the pressure 

differential across the oil separator reaches approximately 8 PSID (.55 Bar).  Replace the oil separator 
element at this time.  If ignored, the unit will shutdown and the advisory will illuminate steadily when the 
pressure differential reaches 15 PSID (1 Bar). 

Using an oil separator element at excessive pressure differential can cause 
damage to equipment.  Replace the separator when the differential pressure is 
greater than 8 psi or every 4,000 hours (at least once a year).