BOCK FK50 User manual

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96003-01.2022-Gb
Maintenance manual
96003-01.2022-Gb
Translation of the original instructions
BOCK FK50
colour the world
of tomorrow
BOCK®
FK50/460 N FK50/555 N FK50/660 N FK50/775 N FK50/830 N FK50/980 N
FK50/460 K FK50/555 K FK50/660 K FK50/775 K FK50/830 K FK50/980 K
FK50/460 TK FK50/555 TK FK50/660 TK FK50/775 TK
FKX50/460 N FKX50/555 N FKX50/660 N FKX50/775 N FKX50/830 N FKX50/980 N
FKX50/460 K FKX50/555 K FKX50/660 K FKX50/775 K FKX50/830 K FKX50/980 K
FKX50/460 TK FKX50/555 TK FKX50/660 TK FKX50/775 TK

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Foreword
Read these instructions before assembly and before using the compressor. This will avoid
misunderstandings and prevent damage. Improper assembly and use of the compressor
can result in serious or fatal injury.
Observe the safety instructions contained in these instructions.
Bock GmbH
Benzstrasse 7
72636 Frickenhausen
Germany
Telephone [phone]
Fax [phone]
[email protected]
www.bock.de
Introduction 4
Safety instructions 5
Product description 8
Short description, nameplate, type code 9
Main and functional parts 10
Dimension drawing, connections 11
Technical data 12
Maintenance 12
Regular checks (at least annually), Oil level check, Oil change 12
Preventive maintenance, emptying the Oil reservoir 13
Recommended spare parts / accessories, Lubricants / Oils 14
Operation of the shut-off valves 15
Fault diagnosis 16
Function faults-symptoms 16
Compressor stand still 16
Compressor cutoff 17
Refrigerant performance too low 18
Compressor temperature too high 19
Oil problems 20
Contents

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Abnormal running noise from compressor 21
Malfunction of the electromagnetic clutch 22
Installation of service kits 23
Shaft seal, Part no. 80023 24
Emptying the oil reseroir, Version ID 007 - 014, Clamping ring with oil felt 25
Capacity regulation, capacity regulation valve Part no. 07541 26
Valve plate 27
Electromagnetic clutch 29
Compressor defects 31
Disassembly of compressor 34
Removal of the compressor from the refrigerant system 34
Disassembly of compressor 34
  1 Removalofallshut-offvalvesandblindanges 35
  2 Removalofoillter  36
3 Removal of the cylinder cover and of the valve plates 37
4 Removal of the shaft seal 38
5 Removal of the oil pump 39
6 Removal of the baseplate 40
7 Disassembly of the connecting rods from the crankshaft 41
  8 Removalofthebearingange  42
9 Removal of the crankshaft 43
10 Removal of the pistons and connecting rods 44
11 Removal of the remaining parts 45
12 Removal of the roller bearings 46
Checking the components of the cmpressor for damage / wear 47
Valve plates 48
Oil pump 48
  Oillter/suctionlter  49
Internal decompression valve 49
Assembly of the compressor 50
1 Fitting the roller bearings 50
2 Fitting the sight glass, the plugs and the internal decompression valve 51
3 Assembly of the pistons / connecting rods 52
4 Fitting the piston / connecting rod sets 53
5 Fitting the crankshaft 54
  6 Installationofthefrontbearingange  55
7 Assembly of the inserted connecting rods / pistons 56
8 Installation of the oil pump 57
9 Fitting the shaft seal 58
10 Installation of the baseplate 59
  11Installationoftheoillter  60
12 Installation of the cylinder cover and valve plates 61
  13Installationoftheshut-offvalvesandblindanges 62
Checking the compressor 63
Tightening torques for screws 63
Spare parts list 64
Exploded drawing 65
Contents

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Liability and warranty
Liability and warranty
Manufacturer‘s liability and warranty are excluded if
• Alterations and functional modifications have been carried out
• No original replacement parts have been used
This maintenance manual is intended to make the repair and maintenance of the FK50 easier for the
servicing personnel. The maintenance manual contains a complete description of each work step for
the disassembly and assembly of the compressor components. Each step must be carefully adhered
to in order tu ensure a reliable repair.
Reminder:
For replacing components Bock provides suitable spare part kits. Yet assembly jobs which go
beyond the replacement of the shaft seal, the valve plates and - if there is one - the capacity
regulator(accessory)shouldbecheckedcarefullyfortheireconomicefciencybeforehand.
The maintenance manual describes the standard type of the FK 40 compressor which we
deliver. Because of different system conceptions, some passages in this service manual may
differ from the unit which you have come across. In these cases the present manual should
be used in analogous fashion.
Introduction
Introduction

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Safety
Safety instructions
Target group of these instructions
• Work on the compressor may only be carried out by persons whose technical training, skills and
experience along with their knowledge of pertinent regulations and documentation means that
they are capable of assessing the work to be carried out and detecting any possible dangers
• Specialist can mean a refrigeration technician for example. Note that electrical work may only
be carried out by a qualified electrician. Alternatively, on a country-specific basis, persons who
have undergone electrotechnical instruction and who have proof of their qualification are also
permitted to carry out the work.
Identication of safety instructions
DANGER Indicates a dangerous situation which, if not avoided,
will cause immediate fatal or serious injury.
DANGER Indicates a dangerous situation which by electrical current, if
not avoided,
will cause immediate fatal or serious injury.
WARNING Indicates a dangerous situation which, if not avoided,
may cause fatal or serious injury
CAUTION Indicates a dangerous situation which, if not avoided,
may cause fairly severe or minor injury.
ATTENTION Indicates a situation which, if not avoided,
may cause property damage.
INFO Important information / tips on simplifying work.

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GEFAHR Danger from electric shock
Compressors contain live parts. Touching these parts can cause
electric shock and lead to serious or even fatal injuries.
• Disconnect the compressor from the power supply before
commencing work!
• Turn the main switch of the plant to "0" (OFF)!
• Secure the main switch to prevent restart!
• Observe the instructions of the plant/vehicle manufacturer!
General safety instructions
WARNUNG Danger due to unqualied personnel
Workwithoronthecompressorbyinadequatelyqualiedpersonnel
can cause serious, or even fatal, accidents and injuries.
• Only adequately qualified persons, such as refrigeration plant service
technicians or refrigeration mechatronic engineers, are allowed to
work on or with the compressor!
• Generally, such persons must be able to assess and judge work and
dangers with and on the compressor!
WARNUNG Danger from malfunctions
If a compressor continues to be operated during extreme running noise
and/or a sharp reduction in refrigerating capacity, there is the danger
of further events occurring, such as the fracture of the housing wall. If
people are standing in the immediate surroundings, there is the risk of
severeinjuryorevendeathfromyingparts.
• In the event of extreme running noise, switch off the compressor
immediately!
• If there is a sharp reduction in refrigerating capacity, switch off the
compressor immediately!
• Secure the compressor to prevent restart!
• In such cases do not continue to operate the compressor under any
circumstances!
Safety

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WARNUNG Danger from pressure
Compressors are pressurized machines containing very high pressures.
They must therefore be handled with extreme caution and care.
Serious and even fatal injuries can occur.
• The maximum permissible overpressure must not be exceeded, even
for testing purposes!
• Depressurize the compressor before carrying out any work on it!
• Wear protective equipment, such as safety goggles or gloves!
WARNUNG Danger from hot parts
Parts on the compressor can get hot. They present a burn hazard.
• Avoid contact with hot parts, such as discharge line valves!
• Wear protective gloves if possible!
• Allow hot parts to cool down sufficiently whenever the situation
requires (during disassembly/installation for example)!
WARNUNG Danger from refrigerant
Severe frostbite and skin damage can be caused if the skin comes into
contact with the refrigerant.
• The skin must never be allowed to come into contact with
refrigerants!
• Wear safety equipment!
• When handling refrigerants, observe their properties!
• Observe the precautionary measures and specifications of the
refrigerant manufacturer!
Safety

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Type code (Example)
FK
Explanation of the type designation
Application
Swept volume
Size
Ester-oillling(HFKWrefrigerante.g.R134a,R407C)
Code letter for series
50 775 NX /
Product description
Product description
Series FK50 vehicle compressors are designed for mobile applications.
Short description
Three design variations are available for different areas of application:
> For air conditioning the K Design
> For air conditioning or normal cooling the N Design
> for deep freezing the TK Design
The differences are mostly associated with the valve plate version which is adapted to each applica-
tionrangewhereoperationalsafetyandefciencyareconcerned.
More features:
Compact 6-cylinder compressor in W design.
Wear resistant and long-lasting engine.
Six sizes as regards capacity.
Aluminium light-weight construction.
Crankshaft supported in roller bearings on both sides.
Bidirectional lubricating oil pump with relief valve.
Variable arrangement shut-off valves.
Ideally equipped with valve plates for each application.
Integrated pulsation damper for especially quiet running.
1. Type of compressor 4. Serial number
2. Volume baláye bei 1450 1/min 5.Oiltypelledincompressorbythe
manufacturer
3. LP: max. tol. stand still pressure intake side
HP: max. tol. Derating pressure high pressure side
}note limits of
aplication diagrams!
Nameplate (Example)
1
2
3
4
5
FKX50/775N
67,6
AR12345A020
19/28bar
Bock GmbH, Benzstr. 7
72636 Frickenhausen, Germany
BOCK
Öl: BOCKlub E55

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Product description
Main and functional parts
1. Cylinder cover
2. Valve plate
3. Compressor casing
4. Integrated leak oil collector
5. Locationholeforttingmagneticclutch
6. Shaft end
7. Shaft seal
8. Connection thermal protection thermostat
9. Discharge shut-off valve
10. Oilllingplug
11. Sight glasses for oil (2x)
12. Baseplate
13. Suction shut-off valve
(FK50/660, 775, 830 and 980
with 2 suction shut-off valves)
14. Oil pump
15.Oildrainplug/oillter
16. Optional connection type
for suction shut-off valve
17. Nameplate
18. Leak oi drain hose
8
13
14
15
9
10
11
16
1
2
4
6
7
3
5
12
17
18

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Dimension drawing
Product description
Connections
A Suction side connection, not lockable 1/8“ NPTF
A1 Suction side connection, lockable 7/16“ UNF
B Discharge side connection, not lockable 1/8“ NPTF
B1 Discharge side connection, lockable 7/16“ UNF
C Oil pressure safety switch connection OIL 1/8“ NPTF
D Oil pressure safety switch connection LP 1/8“ NPTF
E Oil pressure gauge connection 1/8“ NPTF
F Oil drain M22 x 1.5
G Optional connection oil sump heater1) --
H Oil charge plug M22 x 1.5
K Sight glass 2 x 1 1/8“-18 UNEF
L Connection thermal protection thermostat 1/8“ NPTF
M Oillter   M22x1.5
SV1 Optional connection suction valve --
1) = Only possible from factory
- additional SV at FK50/660, 775, 830 and 980 standart
- () = K-Design
DV
Dimensions in mm
Centre of gravity
oil tube
Shaft end

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Technical data
Type Number
of cyl.
Swept
volume
cm3
Displ. volume
(1450 1/min)
m3/h
Weight
kg
Discharge
line
DV
mm / inch
Suction line
SV
mm / inch
Oil lling
Ltr.
Inertia
moment
[kgm2]
Lubri-
cation
Oil pump
FK50/460
6
459 40,1 44 28 / 1 1/835 / 1 3/8
2,6
0,0047
FK50/555 556 48,3 43 28 / 1 1/835 / 1 3/8
FK50/660 662 57,6 42 35 / 1 3/82 x 35 / 1 3/8
FK50/775 776 67,6 41 35 / 1 3/82 x 35 / 1 3/8
FK50/830 831 72,3 43 35 / 1 3/82 x 35 / 1 3/8
0,0056
FK50/980 976 84,9 42 35 / 1 3/82 x 35 / 1 3/8
Connections
Forced feed lubrication
Independent of direction
of rotation
The technical data are the same for the various design variants K, N and TK. In the data concerning the type of compressor, these additions are not taken into account.

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Maintenance
Service intervals
To ensure optimum operational reliability and service life of the compressor, carry out the service
workrequiredonthecompressoratregularintervalsaswellasinaccordancewiththespecica-
tions of the refrigerating plant’s manufacturer.
Oil change
Oil change: In principle, an oil change is not a mandatory requirement, if the equipment is correctly
manufactured and properly operated. Based on decades of experience, we recommend however
that the following oil change/service work is carried out:
• Initialoilchangeduringtherstmaintenanceofthevehicle(atthelatestafteroneyear)
• Thenafterevery5,000operatinghours,atthelatesthoweverafter3years.Alsocleantheoillter.
• An oil change is also necessary, if the oil is very cloudy and dark, or after repairs have been carried
out on the compressor.
Where requirements are higher during use (frequent operation at the limits of application, or
in hotlands with over +40 °C ambient temperature, or in the case of deep freezing), the following
requirements must be observed:
•Initialoilchangeduringtherstmaintenanceofthevehicle(atthelatestafteroneyear)
• Then an oil change after every 2,000 operating hours, at the latest however after two years. Also
cleantheoillter.
Regular checks (at least annually)
• Check the tightness of the compressor and of the plant
• Check the compressor for running noises and vibration development
• Check the oil level in the oil sight glass
• Checktheoilllleveloftheoatingringsealintheoildrainhose
• Draintheoilreservoiroftheoatingringsealafter1,400operatinghoursatthelatest
• Check auxiliary devices, the capacity control for example, for proper function
• Check the pressures and temperatures of the plant
• Check tensioner pulley for correct seating
• Check tension and state of the V-belts
• Checkfasteningboltsforrmseating
• Checkelectricalconnectionsforclean,rmcontactandsupplylinesforchafemarksafter1,400
operating hours at the latest
Oil level check
After starting the compressor, the oil level has to be checked. For this:
The driving engine should be in the „High idle“ operating condition (elevated idling speed)
Compressor running time at least 10 min.
The system should have reached the operating point and steady state.
Check the oil level. Since in practice the installation position of the compressor can be different
(inclined positions), it is recommended to check the oil level in both sight glasses. The oil level must
be visible in at least one sight glass.
Maintenance

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Maintenance
Emptying the oil reservoir
Preventive maintenance
The above requirements for higher use applications also apply in the case of preventive
maintenance. The shaft seal must also be changed after 3 years.
Regular inspections (at least annually): Checks to be carried out on oil level in the oil sight
glass,oilllleveloftheshaftsealintheoildrainhose,absenceofleaksinthecompressor,running
noise, vibrations, pressures, temperatures, and functioning of auxiliary devices such as the capacity
control.
Emptying the shaft seal oil reservoir: As required depending on use, but at the latest after 1 year or
approx. 1,400 operating hours. Since changing the shaft seal involves encroaching into the refrigerant
circuit, this is only recommended, if the seal is losing refrigerant, or if oil is escaping in excess of the
permissible amount. Changing the shaft seal is described in the relevant spare part kit.
Emptying the oil reservoir: The oil reservoir can be emptied very simple without having to dismantle the
coupling and/or belt drive. It is recommended that this is done at the same time as the air-conditioning
maintenanceand motorservice.Toproceed,detachtheoilhose fromthebracket,removethesealing plug
and drain the oil into a collecting vessel.After emptying, reseal the oil hose and clamp it into the bracket.
Dispose of the used oil in accordance with national regulations.
The shaft seal is a wearing part, and its service life depends on the prevailing conditions. Damaging
effects on the shaft seal:
• Too little suction gas superheat, particularly during wet
operation
• Too high or too low belt tension
• Thermal overload (operation outside the limits of application)
• Frequent cycling
• Long periods of stoppage
• Material deposits / dirt from the system
Due to these effects, the shaft seal can develop leaks, and it must then be replaced.

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Recommended spare parts/accessories
Maintenance set for oil change
• BOCK lub E55 2 x 1 l
• Oil drain screw with seal
Maintenance set for shaft seal
• shaft seal kit
• BOCK lub E55 2 x 1 l
• Oil drain screw with seal
Available spare parts and accessories can be found on our compressor selection tool under
vap.bock.de as well as in our online spare parts catalogue at bockshop.bock.de.
Only use original Bock spare parts!
Lubricants / Oils
Theoiltypelledasstandardinthefactoryismarkedonthenameplate,andthisshould
always be used, even in the case of maintenance units. Alternative oil types can vary sig-
nicantlyinqualityduetoadditivesorinferiorrawmaterialsbythemanufacturer.Validation
within the compressors entire operating limits can not be guaranteed, if such alternative oil
types are used. It is for this reason, that we only recommend the use of oil from Bock! Bock
assumes no liability for any damage arising from alternative oil types.
Refrigerant Bock standard oil grade
HFC
(e.g. R134a, R407, R 404A)
BOCK lub E55
HCFC (e.g. R22) BOCK lub A46
Maintenance

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Opening the shut-off valve
Spindle 1: Turn to the left (ccw) until the end stop.
-> Shut-off valve fully open / Service port 2
closed
Opening the service port (2)
Spindle 1: Turn 1/2 -1 turn to the right
-> Service port 2 open / Shut-off valve open
Port 3 is intended for safety devices and cannot
be shut-off.
Note: Before opening or closing the shut-off valve, loosen the valve spindle
seal (Fig. left) by 1/4 turn. After operating the shut-off valve, tighten the valve
spindle seal carefully again (Fig. right).
Operating of the shut-off valves
1
3
2
3
2
1
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 

 
 
 

⇒
  

 
 

⇒   


     

    
    
  
 


  
 

 
 

 
   
        
 

 
 
 

⇒
  

 
 

⇒   


     

    
    
  
 

Maintenance

- 16 -
96003-01.2022-Gb
Fault diagnosis
In case of malfunctions during compressor operation we recommend to prepare a measurement record
for aiding the fault search:
Pressure measurement: Discharge side, suction side,
oil pressure
Temperature measurement: Compressor casing,
discharge end temperature, suction gas overheating
Oil level
Compressor speed
According to the expected cause of the fault it may be necessary to check the electrical systems for
faults in the control.
In order to localize the causes of operating malfunctions as easy as possible we have compiled
the following table with suggestion for remedying compressor malfunctions. Further information is
retrievable under vap.bock.de (mobile applications -> tools -> online analysis). Additionally a failure
analysis slide is obtainable under [email protected].
Function faults - Symptoms
Function faults arising most frequently and their symptoms are:
Compressor stoppage, compressor cutoff
- Compressor does not start
- Compressor starts and then stops again
Refrigerant performance too low
Too high compressor temperature
Oil problems
Abnormal compressor running noise
Fault diagnosis
Compressor stand still
Compressor stand still
Compressor does not start
Problem Possible cause Remedy
Control circuit is inter-
rupted / no control by
control element
Main - or control fuse is switched
off or tripped
Replace fuse
Determine and remove the cause
Cut off through:
- Low pressure switch
- High pressure switch
- Heat protection thermostat
- Control thermostat
- Other safety elements
Locate the interruption in the
circuit and remove the cause of
interruption
Malfunction of electro-
magnetic
coupling
- see also page 20 "Malfunction
of electromagnetic coupling"
Checking

- 17 -
96003-01.2022-Gb
Fault diagnosis
Compressor cutoff
Compressor starts and stops again
Problem Possible cause Remedy
Cutoff through low pres-
sure switch
Suction pressure too low:
- Check the setting of the low pres-
sure switch
- Adjust the switching points or
replace switch
- Suction valve of the compressor
closed
- Open suction valve
- Capacity of compressor too large - Check operating conditions
-Refrigerantdeciency - Leak test / add refrigerant
- Filter / dryer in the liquid line
blocked
-Replacelter/dryer
- Expansion valve not functioning
properly
- Check the setting of the expansion
valve
- Solenoid valve on the liquid line not
opening
- Check the control / function
- Evaporator clogged (dirt / ice) - Remove cause
- Evaporator fan defective - Remove cause
- Pipeline damaged - Remove cause
Cutoff through high
pressure
switch
Condensing pressure too high:
- Check the setting of the high-
pressure switch
- Adjust the switching points or
replace switch
- Pressure valve of the compressor
closed
- Open the pressure valve
- Condenser fan not functioning - Check the control / replace motor
- Condenser performance insuf-
cient,condenserandfanmotor
contaminated
-Cleaningofcondensernsandfan
-Excessiverefrigerantlling -Extractrefrigeranttonormallling
- Non-condensible gases in refriger-
ant
- Extract refrigerant and evacuate
the
refrigerationplant/rellrefrigerant
- Pipeline damaged - Checking and repairing the pipeline

- 18 -
96003-01.2022-Gb
Fault diagnosis
Cutoff through heat
protection
thermostat (acces-
sory)
Discharge end temperatures is
too high
- Operating limits of compressor
exceeded
- Adapt the operating conditions
to the operating range
- Suction gas overheating - Check expansion valve / check
insulation on the suction side
-Condensercoolinginsufcient - Check fan motors / cleaning of
condenser
- Valve plate damage - Replace valve plate
- Internal decompression valve
has opened
- Replace decompression valve
-> Check compressor and
refrigeration plant Determine
and remove the cause for the
inadmissible high pressure in
the high-pressure side
Cutoff through control
thermostat
Temperature over / below the
desired range
Check operating points
Problem Possible cause Remedy
Suction pressure too
high
- Expansion valve not functioning
properly
- Check expansion valve setting;
replace valve, if necessary
- Lack of compressor capacity - Check the function of the
compressor by evacuating to
vacuum.
Check function of capacity
regulator
(accessory)
- Shortage of refrigerant -Runleakagetest/rell
refrigerant
Suction pressure too
low
- See „Cutoff through low-pres-
sure switch“
- Checking
High-pressure too high - See „Cutoff through high-
pressure switch“
- Checking
High-pressure too low - Condenser being cooled to
much
- Adjust the control of condenser
cooling
- Lack of compressor capacity - Check compressor / Check the
functioning
of capacity regulator
Refrigerant performance too low

- 19 -
96003-01.2022-Gb
- Pressure laminations of valve
plate leaking
- Replace valve plate
- By-pass between suction and
discharge side
- Localize leak between the
discharge and suction side and
repair it
- Lack of refrigerant - Carry out leakage check / top
up refrigerant
Power regulator
activated
- Malfunction - Check function
V-belt slips - missing voltage - Adjust voltage
Problem Possible cause Remedy
Suction gas temperature
too high
- Suction gas overheating - Adjust expansion valve
Insulate the gas suction line
-Toolittlerefrigerantlling -Establishtheoperatinglling(see
Operating
Instruction for the refrigeration
plant),
localize leak
-Liquidlterblocked -Clean/replacelter/dryer
- Shortage of refrigerant - Run leakage test/rellrefrigerant
Discharge pipe tempera-
ture
too high
- Suction gas temperature too high
(Condensing pressure too high)
- Adjust expansion valve
Insulate the gas suction line
- see „Cutoff through high-pressure
switch“
- Operating limits of compressor
exceeded
- see „Cutoff through heat-protection
thermostat“
-Coolinginsufcient -Checkrefrigerantlling
- Adjust expansion valve
- Short circuit between the discharge
and the suction side of the com-
pressor
- Check gaskets on valve plate /
change
- Valve plate damage - Replace valve plate
- Internal decompression valve has
opened
- Replace decompression valve (see
the section on Disassembly / As-
sembly of Compressor)
Refrigerant performance too high

- 20 -
96003-01.2022-Gb
Fault diagnosis
Problem Possible cause Remedy
Oil pressure too low - Refrigerant in oil - see „Oil foams“
- Too little oil in compressor - Add oil and search for the
cause of oil loss
-Oillterdirty/blocked -Clean/replaceoillter
Change oil
Oil foams during start-
up phase
- Liquid refrigerant has moved
into the oil sump
- Check the laying of pipes
- Installation of the check valve
in the
discharge line / check
- Installation of the solenoid
valve in the
liquid line / check
- Check the control
Oil foams during
operating
- Expansion valve not functioning - Adjust / replace expansion
valve / check
Oil level decreases - During start-up, a portion of the
oil is carried to the refrigeration
plant with the refrigerant
- Refrigerant and oil get mixed.
After some time the oil level
should stabilize.
Add oil, if necessary.
- Refrigerant in oil - see „Oil foams during start-up
phase“
- Piston rings worn - Replace piston rings
- Suction / discharge laminations
of the valve plate leaking
- Replace valve plate
- Oil return disturbed - Remove cause
- Lack of refrigerant - Remove cause
Oil problems