Sperre HLF2/77, Instruction Manual

Instruction manual for compressor type HLF2/77 

Page 12 

FAULT TRACING CHART 

1.  Compressor capacity is low, or the compressor is not delivering full pressure 
Possible causes 

Remedy 

Dirty, damaged or worn valves. 

Clean and check all valve plates, springs and 
gaskets. Replace defective parts. 

Carbon deposits on valves. 

Piston rings are worn. Replace.  
Unsuitable lubricating oil. Change oil brand. 

Piston rings are stuck. 

Loosen and remove piston rings.  
Clean piston ring grooves and rings.  

Air filter clogged. 

Clean filter. 

Air leaking to surroundings or leaking inside the 
compressor through valve gaskets and valve 
plates. 

Check for external leakages with soapy water. 
Check valve gaskets and valves. 

Faulty automatic control equipment. 

Inspect components and circuits. 

2. Safety 

valve 

blows 

Possible causes 

Remedy 

Closed air line valve. 

Open the valve. 

Carbon deposits in non-return valve. 

Clean the valve. 

Faulty adjustment of automatic system. 
Compressor does not stop when air reservoir is 
full. 

Check pressure switch and automatic circuitry. 

Safety valve damaged or defective (causing it to 
open at lower pressure). 

Replace safety valve. 

3.  Valves require maintenance too frequently 
Possible causes 

Remedy 

Overheating. 

High ambient temperature. Improve fresh air 
supply. Carbon  deposits in coolers. Clean 
coolers. 

Dirt or foreign matter in intake air. 

Air filter damaged. Improve suction air quality. 

Cooler tubes dirty. 

Clean. 

4.  Bearings and bearing housings running hot. Lub. oil overheating. Noise from bearings 
Possible causes 

Remedy 

Damaged or worn bearings. 

Replace bearings. 

Uneven wear on crankshaft bearings. 

Check crankshaft for straightness. 

Low oil level. 

Refill lub. oil. 

5.  Piston running hot 
Possible causes 

Remedy 

Worn bearing on flywheel end. 

Check little end bearing, piston rings and piston 
clearance. 

Piston and/or rings binding in cylinder. 

Ensure cool fresh air supply to cooling fan and 
suction air filter. If the piston has completely 
seized, wait a while before turning over the 
compressor. Clean cylinder and piston, fit new 
piston if necessary. 

CCG DOC NO. 346055