Haier HRFN-250DAA User manual

CAUTION
READ THIS MANUAL CAREFULLY TO
DIAGNOSE TROUBLE CORRECTLY
BEFORE OFFERING SERVICE.
Refrigerator
SERVICE MANUAL
Features:
1. Mechanical temperature control
2. Adjustable thermostat
3.100% HFC free and FCKW free
4. External condenser and adjustable feet
5. stylish interior light
MODEL: HRFN-250DAA
Haier Grou
p
HRFN-250DAAS

CONTENTS
CONTENTS························································································································1
SAFETY PRECAUTIONS ·································································································· 2
SPECIFICATIONS·············································································································· 4
PARTS IDENTIFICATIONS································································································ 6
SYSTEM FLOW PRINCIPLE ····························································································· 7
CIRCUIT DIAGRAM··········································································································· 8
MAINTENANCE SERVICE AND TROUBLE SHOOTING ················································· 9
ANALYSIS OF TROUBLES AND TROUBLESHOOTING ················································13

SAFETY RECAUTIONS
1. Check if there is any leak of current.
2. Cut out the power supply before the repair to avoid an electrical shock hazard.
3. In the case of a live-line test, insulating gloves should be worn to avoid potential electrical shock.
4. Confirm the rated current, voltage and capacity before testing with any kinds of instruments.
5. Watch if the upper door is open when you check something at a lower position.
6. Take out every part in the cabinet before moving the machine, especially things like panels (e.g. glass
shelf).
7. Please wear intact cotton gloves wh en repair any parts of the evapor ator, so that scr atches by th e
sharp fins can be avoided.
8. If there is a breakdown with the refrigeration system, please surrender the machine to the service
center, else the leaked refrigerant may pollute the atmosphere.
9. The refrigerator use AC of 220V with a frequency of 50Hz.
10. A big fluctuation of voltage (exceed the range 220～240V) may cause a start failure of the refrigerator,
a burn -out o f the control p anel and compressor, or an abn ormal sound from the co mpressor in
operation. In this condition an automatic voltage regulator over 750W should be added.
11. Take care not to damage the supply line. Don’t yank at the line; pull the plug out gently from the
receptacle. Don’t press the line under the cabinet or step on it. Take care not to roll on or damage the
supply line when moves the machine from the wall.
12. Don’t use the supply line any more when there is damage to the line or an abrasion to the plug. Go to
the authorized service center for a replacement.
13. In the case of leakage of inflammable gases like carbon monoxide, open the door and windows. Don’t
pull out or insert the plugs of the appliance.
14. This product is designed only for h ousehold use. Any put of medicine, dang erous flammable,
explosive articles and highly corrosive acid or base is forbidden.
15. It is recommended not to put any receptacles, stabilized power suppl y or appliances like microwave
oven on the board of the refrigerator. Don’t use appliance within the refrigerator (except recommended
type), else there may be electromagnetic interference or other accidents.
16. Don’t store or use gasoline and other flammable articles near the refrigerator which may lead to a fire

-accident.
17. Don’t hook on the door , else the door may be sl anted or the machine may be tipped ove r and inju re
people.
18. Don’t place unstable articles on the refrigerator (e.g. weight s and c ontainers with water), else th e
weights may hit people and the leaked water may cause leak of current.
19. Don’t touch the refrigeration surface of the freezing compartment when the refrigerator is in operation,
especially when your hand is wet, else you may be glued to the surface.
20. Don’t spray at the refrigerator, or locate it at a damp place, else the insula tion of the refrigerator may
be impaired.
21. Any disasse mbly or alter nation to the refrigerator is strictly forbidden. Da mage to the refrigeratio n
pipeline is prohibited. Service to the refrigerator must be carried out by professionals.
22. Don’t put bot tles of bear and othe r drinks into the refrigerator; else the bottles may be cracked wit h
cold.
23. Pull out the plug of power suppl y du ring clearan ce or power out age. Wait at least fiv e minutes to
resume the power supply in order to prevent damage to the compressor caused by continuous restart.
24. Remove the door an d the door seal when the r efrigerator is out of use, in case that a ccident may
happen to children coming in to play.

SPECIFICATIONS
REFRIGERATOR
1. Model HRFN-250DAA
Photo
Commercial brand Haier
Product description REFRIGERATOR
Type of Appliance (FS= freestanding BI= built-in) FS
Energy efficiency class A +
Climate class (N= + 18-32 °C T=+ 18-43 °C) N
Freezer compartment / Star rating 4
2. Key features
Gross capacity l 277
Total net capacity l 213
Defrosting ( H=manual A=automatic) Fridge/Freez H
Defrost water outlet /
Air circulating ventilator Yes
Kind of coolant (R134a/R600a) R600a
Foaming components C-P
3. Technical data
Voltage / frequency V/Hz 220-240 V~/ 50
Input power / mains fuse minimum W /A 100W/0.5A
Temperature range (from>to) Fridge/Freez °C 0-10°C / ≤-18°C
4. Aesthetics
Colours (see L):
Top cover White
Cabinet White
Door Frame White
Fascia panel / Handle White
Inside door/-drawers (w =white t=transpar.) - t-
Door:
F= Flat / R= Rounded / S= Streamline S

Hinged (r =right l =left) / reversible) r / reversible
Lock （yes/not） No
Drawers/ CRISPER:
Number n°. 1
Crisper:
Salad crisper(s) transparent / white -t-
5. Equipment & Accessories
Control Panel:
Thermometer interior / exterior interior
Control lamps green / yellow / red /
Over temperature ALARM LED / acoustic /
Adjustable thermostat Yes
Fast freeze switch /
Interior light W YES
Adjustable feet front / rear n° front
Castors front/rear /
6. Product dimensions
Unit dimensions H / W / D cm 144*54.7*57
Depth with open door cm 108
Net weight kg 47.0
7. Packing dimensions & loadability
Packing dimensions H / W / D cm 148x 57.8 x59.8
Gross weight kg 53.0
8. Recycling s ymbols
Carton weight in g kg 5
9. Service
Users instruction (languages) D / GB /F / I / E
10
.
Others

PARTS IDENTIFICATIONS

SYSTEM FLOW PRINCIPLE
1. Schematic Diagram of Refrigerating Principle
2. Brief Description of System Flow Chart
3/6 series is a direct cooling single-system refrigerator
which has a freezer compartment.
When the refrigerator is just powered on, the
refrigerant flows in the sequence:
1->2->3->4->5.

CIRCUIT DIAGRAM
CIRCUIT DIAGRAM

MAINTENANCE SERVICE AND TROUBLE SHOOTING

5.2. Normal Phenomena—Not Troubles for Refrigerators
In a domestic refrigerato r, there is n ot only a complicated electric control system, bu t also a
refrigerating system that is dif ficult to discern whether it is in a good working conditio n. Both the
systems are related a nd af fect each other. If a cert ain p art of a refrige rator wo rks abnormall y .It s
refrigerating efficiency will decrease ,operat ion properties will become unst able ,or even it cannot be
used normal ly for those serious case s. Refrigerators are ge nerally of larg er volume ,o nce troubles
appear ,to send them to a service department is really a tough thing ,if such is the case ,the user will
always be in suspense ,s ometimes ,normal phenomena will be erroneously regarded as
troubles .Therefore ,before we deal with the topics of frequently occurring troubles of refrigerators and
their remedi es ,we shou ld firs tly give a brief account of some normal phen omena which are n ot
troubles .In case any one of such phenomena occurs ,there is no need to worry about it ,a nd the user
can use it at total ease .
1).When the compressor of a refrigerator has just stopped running ,a rumbling sound can be heard
from inside it s evaporato r .This is a sound caused by th e flowing of r efrigerant in the evapo rator
tubing .Because the pr essure dif ference is still greater af ter the compressor has just stopped
running ,the refrigerant will flow for a certain time , therefore ,this sound is a normal phenomenon.
2).A click sound can often be heard from the refrigerator .This is a normal sound p roduced by the
pull-in or release of the armature of a current dead weight st art relay whe n st arting the
compressor .The compressor motor w ill produce a slight and uniform sound while it is running .This
sound is not easy to be heard in the
daytime ,but of course it can be heard distinctly at night.
3).The compressor consist s of an electric mo tor and a compre ssing apparatus .During it s normal
operation ,the motor ’s stator core and windings w ill rise to a temperature in the range of 100 ℃ ~110
℃ ,and the temperature of the pi ston and cylinder of the compressing mechanism can also reach as
above 100 ℃ due to the heat produced when compressing refrigerant .Most of the heat radiates to the
air throu gh t he compres sor casing ,therefor e ,it s casing is gener ally at a temperatur e betwee n 85
℃~90℃ ,it is very hot ,particularly in summer when the ambient temperature is higher .All these are
normal phenomena .
4).For the dir ect cooling refrigerato r ,a kind of irregular crack so und can be often heard when the
compressor is running for a certain period of time or has just stopped its running .This sound is caused
by the stress relief due to exp ansion and contraction when temperature changes ,and will not affect
the normal application of refrigerator .
5.3. Common Troubles in Refrigerators and Their Remedies
Causes for troubles occurring in refri gerators are closely related to the qual ity of components and
workmanship in assembling by ma nufacturers as whether refrigerato rs are prop erly used an d
maintained .The parameters generally used to express the working conditions of a refrigerator include
the temperature inside the refriger ator ,operation rate ,electric power consumption ,noise level ,an d
other functional indexes .If any one of
these parameters is beyo nd its permissible range ,this indicates that there is a fault or trouble in the
refrigerator . During the whole service life of a refrigerator ,the probability of troubles occurring within a
union time i s called it s failure r ate .Making a co mparison be tween the c ontrol circuit system of a
refrigerator and its refrigerating system ,we can find that the failure rate of the former is higher ,an d
that of the thermostat is the highest . In
troubleshooting ,the first thing you must do is to determine where the trouble comes from --- the control

system or th e refrigerating system .There is general no trouble indicating instrument mounted on the
domestic refrigerato r ,locations and natures of troubles shou ld be deter mined according to their
respective features ,there fore ,exp erience in servicing is very important to troublesho oting .Servic e
technicians with rich exp erience can correctly locate them and t ake reasonable r emedy measures
based on their compreh ensive analysis of trouble characteristics as well as operating conditions for
various kinds of refrigerators .
Three Essentials for Checkup
1) Look
a) Check the tubing of refrigerating system for cracks and various welding point s for leaks ;if
leakage occurs ,an oil stain can be seen definitely .
b) Check the suction and exhaust pressure values (high pressure and low pressure) of compressor
to see whether they are normal .
c) Check the conditions of frost attached to its evaporator and gas return tube .It is abnormal if frost
has formed on part of the evaporator or there is no frost attached to it .
d) Pay attention to the speed of temperature drop inside freezer compartment .It is abnormal if the
speed of temperature drop is obviously slower than the corresponding normal speed .
e) Check the environment to see whether it is suitable for placing a refrigerator .
f) Check refrigerator door seal ,case ,table surface and heat insulation layer .
g) Look at the main control board to ascertain if various indication states are normal.
2) Listen
a) Listen to the noises p roduced wh en the comp ressor is running Hums from a fully enclosed
aggregate u nit is the sound cause d by overl oad indicating that the motor cannot be st arted
normally ,meanwhile ,a clattering sound can be h eard from inside the start relay ,which is produce d
because the st art contacts cannot be released no rmally .A whis tling sound is c aused b y the high
pressure gas flowing out of the crack of the pressure tube inside the compressor ,and clucks are the
sound of striking after the suspended spring inside the compressor has broken .
During the n ormal oper ation of compressor ,a s light and unifo rm hum s ound due to u ndulation of
electric current can be heard gener ally ,this is a normal phenomen on .Howe ver ,if it sounds like
“tong ,tong …”,i.e., an imp act sound inside the comp ressor ,this means that a large quantity of wet
vapour of refrigerant or refrigerating oil has come into the compressor cylinder ;if it sounds like
“dang ,dang…”, a striking sound of metal parts inside the compressor ,this means that some moving
parts have loosened (note to differentiate this
sound from those formed during starting or stopping the compressor).
b) Listen to the sound caused by t he flowing of gas in the evaporator Open the refriger ator door
while the co mpressor is in oper ation ,incline your ear and listen attentively the gas flow sound inside
the evaporator .If it sounds like gentle whistling accompanied by a sound similar to water flowing ,this
is the sound produced by the n ormal circulation of refrigera nt within the e vaporator .In case only th e
gas flowing sound can be heard and there is no water flowing sound ,this indicates that the refrigerant
has already percolated .If neither the flowing sound nor the gas s ounds from the evaporator can be
heard ,this means that the filter or capillary has been clogged .
3)Touch and Feel
a) Feel the compressor when run ning ,its temperature should b e gener ally less than 90 ℃ in the

normal state (it may exceed 90 ℃ in case of running for a longer period of time ).
b) After the compressor has operated normally for 5~10 minutes , ouch and feel the condenser ,the
temperature of its upper part should be higher than that of its lower part (or its right part is hotter than
its left part ,depending on the type of condenser coil ),this indicates that the refrigerant is circulating . If
the condenser is not hot ,this means the leakage of refrigerant .In case the condenser radiates heat for
only several minutes and then cool s down ,this m eans that the filter and capillary have been
clogged .As for the forced air cooling condenser ,hot air will be blown out of it ;this means that the
system is out of order .
c) Feel the filter ’s temperature .During t he normal opera tion of refrigerating system ,the
temperature on the filter’s surface should be a little higher than the ambient temperature ;if you touch it
with your hand ,you will have a sense of slight heat .In case dew condensation appears due to the fact
that its temperature is obviously lower than the ambient temperature ,this means that most meshes of
its screen has been clogged ,resulting in an
obstructed flowing of refrigerant ,thus causing a drop in temperature due to throttling .
d) Feel the temperatu re of ex haust gas from the refrigerating system .the exhaust gas should b e
very hot and this is the n ormal working state .For those refrigerator with enclosed type of compressor
refrigerating system, no frost or dew drop will fr om on the gas suction t ube ,otherwise ,there is
something wrong in the system (Frosting and dew condensation may appear for a very short time
period when just st arting the machine ,this is a normal p henomenon ). Becaus e a ref rigerator is a
combination of several compone nts ,they are re lated and have influence on each other .In case an
abnormal phenomen on h as been found through the abov e-mentioned ch eckups ,you need not to
make a hasty conclusion based on o nly one abnormal phenomenon .It is advisable to find out two or
more abnormal phenomenon ,or conduct troubleshooting comprehensively with the aid of instruments
or other ways ,because sever al kinds of troubl es may share a common abnormal ph enomenon ,and
two or more abnormal p henomena may occur simult aneously due to a cert ain trouble .With this
method ,you can reject some suspicious troubles and finally make a correct judgment .
5.4 Compressor doesn’t start

Com pressor
doesn’t start
Whether lighting
and display system is
normal
W hether the
grade of thermostat is
on 0
Whether the
resistance of com pressor is
infinite or 0
Whether the
starting current is
about 5A
抯
Whether PTC starter
resistance between running jack
and starting jack is 16-50 O
Measure whether
two ends of heat protector
is through
Whether the finger
of multimeter swing to 0 quickly
and then swing back slowly
when measuring two
poles of capacitance
Whether
抯
compressor pin is tight,
contact
is good
Whether input
and output voltage of main
control board is normal
Whether each
contact of main control board
is normal
Tighten each
contact and test machine
again
Y
Trouble of lighting and display system
Adjust the grade according to fact
Compressor is open circuit or short
circuit
Inner trouble of compressor
If it is infinite or 0, then the starter is
out of work.
Heat protector is out of work
Capacitance is out of work
Insert again, electrify and test
Main control board is out of work
Change for a new compressor
Y
N
N
N
Y
Y
Y
Y
Y
N
Y
Y
Y
N
N
N
N
N
Compressor doesn’t start
sometimes because the
temperature in case is
between starting and stop
temperature, should pay
attention when do test
Adjustment of thermostat
Temperature of
environment
>30℃ 1-3 grade
16-30℃ 3-5grade
<16℃ 5-7grad

ANALYSIS OF SERVICE AND TROUBLE SHOOTING
Part 6 Analysis of Troubles and Troubleshooting
A. Poor Refrigerating Effect
The so-called “poo r refri gerating effect “ refers to the fact that the refr igerator can ope rate an d
refrigerator normally ,but the temp erature in t he refrigerato r cannot drop to the prescribed valu e
under the stipulated w orking conditions .In view of there ar e many causes for this phen omenon ,we
are going to discuss and analyze it in the following 7
aspects :
1) Leakage of refrigerant
ANALYSIS OF TROUBLE
The leakage of refrigerant in t he system will result in an insuf ficient refrigerating capacity ,th e
resulting phenomen a ar e it s lower gas suction pressure an d exhaust pressure as well as highe r
exhaust gas temperature .The exhau st tube feels rather hot ,and a continuous gas flo wing soun d
louder than usual can be heard at the outlet of the capillary ,and no frost or a smaller quantity of loose
frost appears on the evaporator .After shut down ,the balance pressure in the system is usually lower
than the saturation pressure corresponding to the same ambient temperature .
REMEDY
In case there is leaka ge of refrigerant from the system ,do not h urry to recharg e it with
refrigerant ,manage to f ind out leak point s immediatel y ,an d make a n ote of from wher e it lea ks
---welding points and parts .After having them repaired ,recharge refrigerant . There are so many joints
and sealed surfaces in a refrigerat or ,accordingly ,quite a lot potent ial le ak point s do exist in the
system .In troubleshooting ,pay attention to those parts that are liable to leak ,check main connection
points for oil seepage and tubing for cracks .If there is no severer leak point ,charge the system with
nitrogen and detect leak points with the commonly adopted method ,repair them ,evacuate ,charge the
system with refrigerant ,and then turn on the refrigerator to make a test run .
2) Too much refrigerant charged into the system
ANALYSIS OF TROUBLE
a) In case the amou nt of refrigera nt charged in to the syste m exceeds it s nominal cap acity ,the
superfluous refrigerant will of course t ake so me sp ace of the evaporat or ,thus reducing it s
heat-dissipation area and hence the refrigerating efficiency of the system .The abnormal phenomena
caused by this reason are as follows :the gas suction and exhaust pressures are generally higher than
their respective normal values ,the temperature of its condenser is higher and the electric current of
the compressor rises ,lo ose frost fo rms on the evaporator ,the refrigerator temper ature drop s
slowly ,and frost appears on the gas return tube .
b) In case excessive refrigerant has been charged ,the liquid refrigerant that cannot evaporates in the
evaporator will return to the compressor ,and thus a phenomenon of “liquid st riking” will o ccur .The
liquid refrige rant evap orates and ef fervesces as soon as it flows into the refrigerati ng oil at th e
bottom of compressor .If the condition is severe ,foams will fill all over inside the compressor housing
and be sucked by the piston ,causing damage to the components of compressor .
REMEDY
ccording to the ope rating procedu res ,it is mandator y to turn the machine of f ,and everal minute s
later ,open the refrigera nt charging tube and let t he refrigerant escape om it ,replace the dry

filter ,recharge refrigerant after evacuating ,and then seal the harging port .
3) There is air left in the refrigerating system
ANALYSIS OF TROUBLE
residual air in the refrigerating system will reduce its refrigerating efficiency .The rominent phenomena
are the increase in it s gas suction and exhaust pressures however ,the gas exhaust pressure will not
exceed its rated value ),obvious increase in emperature in the segment from the compressor outlet to
the condenser inlet .Because here is air in the system ,both the gas exhaust pressure and temperature
will rise ,and oreover ,the gas flowing sound is intermittent and obviously louder .
REMEDY
After shut down for sever al minutes ,open the tubing ,evacuate it and then r echarge the System with
refrigerant .
4) Low efficiency of compressor
ANALYSIS OF TROUBLE
Low ef ficiency of a refrigeratin g compressor re fers to the actual r eduction of g as discharg e
Capacity ,and hence the corresponding reduction of refrigerating capacity ,under the Condition that the
refrigerant in the system is unchanged .This phenomenon occurs mostly When the co mpressor has
been used for quite a lo ng time ,it s moving parts have worn to a Conside rable degree ,fit clearance
between various parts have increased and sealing Property of its gas valve has deteriorated ,resulting
in an decrease in its actual gas Discharge capacity .
METHODS OF JUDGMENT
Measure the high and low pressures with pressu re gauges to see whether they are Normal .If an
abnormal sound comes from the compressor or th e temperature of its Causing is too high ,Cut the
discharge port open and operate the compressor ,feel it if There is pressure at the discharge port with
your finger (For a normal compressor ,its Discharge port is difficult to be blocked with your finger if you
just apply a little effort).
5) Too thick frost layer formed on evaporator
ANALYSIS OF TROUBLE
If a direct cooling r efrigerator is to be used for a prolo nged period of time ,be sure to defrost it s
evaporator regularly ;if you fail to do so ,the fros t layer on the evaporator tubing will become thicker
and thicker .Heat conduction will be severel y af fected when the whole tu bing is wrapped with a
transparent ice layer ,and finally the temperature in the refrigerator cannot drop down to the prescribed
range .
REMEDY
turn the refrigerator off ,and make pre parations for defrosting ,open th e refrigerator door to let the air
come in ,or use a fan to speed up air flowing so a s to shorten the time nee ded for d efrosting .Never
strike the frost layer with any iron to ols or wood stick in order to avoid d amage to the evap orator
tubing .
6) Refrigerating oil left in evaporator tubing
analysis of Trouble
During th e process of refrigerating cycles ,a little refriger ating o il may remain in th e eva porator
tubing ,and af ter a longer time of o peration ,if ther e is considerable ref rigerating oil lef t in the
evaporator ,the heat conduction ef fect will be severely af fected ,thus causing a poor refrigerating
effect .

REMEDY
It is quite dif ficult to determine whet her this trouble is cause d by the refrigeratin g oil lef t in the
evaporator tubing ,b ecause this kind of phe nomenon a nd other severa l trouble a re tends to b e
confused .Gener ally spe aking ,you can make a ju dgment based on the frost formed on the
evaporator .If the frost does not cover the evap orator , and moreo ver ,it is loosely for med ,you can
make a judgment that the deterioration of refrigerating effect is due to the accumulation of refrigerating
oil left in the evaporator tubing in case no other troubles have been found . To clear off refrigerating oil
left in the evaporator ,dismantle the evaporator ,purge it thoroughly and then dry it .In case it is difficult
to dismantle it ,charge refrigerant from the evaporator inlet to wash it several times ,then purge and dry
it with nitrogen .
7) Flowing obstructed in refrigerating system
ANALYSIS OF TROUBLE
Because the refriger ating system was originally not purg ed t horoughly ,som e of the filter screen
meshes have been clog ged by di rt accu mulated in the filter af ter using it for a cert ain time of
period ,thus resulting in a decrease in flow rate ,and hence a poorer refrigerating effect .
The abnormal phenomena caused by this kind of slight clogging in the system are as follows: the gas
discharge pressure is lower ,the temperature of discharged gas drops down ,the position clogged has
a temperature lower than that in normal conditions ,and for a severe clogging ,even dew condensation
as frosting may appear .
REMEDY
Purge the tubing ,and after replacing the dry filter with a new one or clearing it thoroughly ,recharge the
system with refrigerant and seal the charging port .
B. No Refrigerating
The phenomenon that the compressor runs normally ,but no frost (or only a little frost ) appears on the
evaporator ,and the refrigerator temperature does not drop down is called “no refrigerating”. There are
many causes for this trouble and it is relatively complicated , too . In servicing ,special attention to
finding direct causes for this phenom enon .Three main potential causes for this trouble are an alyzed
below :
1) All refrigerant in the system has leaked out
ANALYSIS OF TROUBLE
Leak points in the refrigerating system have not been found an d repaired timely ,thus resulting in the
total escape of refrigerant .There are two kinds of leakage :I) slow leakage for instance ,when we want
to use a refrigerator that has been put out of quite a long time ,we find the leakage of refrigerant ,or in
the course of its operation ,we have found that th e refrigerator is gradually becoming no t so cold and
finally no refrigeratin g cab be achieved ; ii) fast leakage in that case ,all the refrigera nt will escape
swiftly due to abrupt rupture of system tubing .
Symptoms of total leakage of refrigerant are mainly as follows : the compressor can be st arted easily
(if there is no damage to the compressor parts) and its operating current becomes low ,its gas suction
pressure is high and discharge pressure is lower ,the gas discharge tube feels rather cold ,no sound of
gas eruption from the liquid in the evaporator can be heard ,and no will gush out of the process tube if
you cut it open after shutdown .
REMEDY
Check the whole machine , particularly those locations which are liable to le ak .After leak points have

been fou nd ,rep air them or repl ace them with new parts according to spec ific circumst ances ,then
evacuate the system and finally charge refrigerant.
2) Refrigerating system has been clogged
a) Clogged with Ice
ANALYSIS OF TROUBLE
The dryness treatment for the major p arts in the refrigerating system has been performe d improperly,
the effect of air purging for the whole system is not good ,or the water content in the refrigerant is out of
standard ,all these will cause the expansion valve to be clogged with ice .The symptom for this trouble
are as follows :the refrigerator som etimes can refrigerate and sometimes cannot :the refriger ator
compartment works normally at the beginning ,but af ter working for a certain period of time ,frosting
begins at the clogged position ,evaporation temperature reaches below 0 ℃, water will accumulate at
the narrow part of the capillary and clog it gradually ,then frost begins to melt at the evaporator ,no gas
flowing sound can be heard ,and the gas suction pressure assumes a state of vacuum .Note that these
phenomena will appear intermittently ; sometimes ,the
refrigerator works well ,and sometimes not well .In order to determine whether it is clogged w ith
ice ,heat the suspicious points with hot water to make ice melt ,and after a while if a gas flowing sound
resulting from an abrupt gush is heard and the ga s suction pressure rises as well ,it can be confirmed
that the trouble is caused by ice clogging .
REMEDY
If there is too much moisture in the refrigerating system, it is advisable to release the refrigerant, purge
the tubing with nitroge n, and then charge the system with the f iltered refrigera nt. Howeve r, the
commonly adopted method is to connect a filter with moisture absorbers (such as silica-gel, anhydrous
calcium chloride) to the refrigerating system so a s to filter out the moisture from the system, then
replace the filter, evacuate it again and
finally charge the system with refrigerant.
b) Clogged with dirt in capillary
ANALYSIS OF TROUBLE
The capillary inlet is a place where coarse-grained dirt or refrigerant oil in the system will tend to settle
down and clog it. In case considerable dirt accumulates there, the whole filter screen may be blocke d
totally, making the refrigerant unable to go through. Clogging with dirt exhibits the same symptoms as
that with ice, namely , higher gas suction pressure, lower tempe rature of discharged g as, and no gas
flowing soun d from the evapo rator. The dif ference between the both is as fo llows: if the clogging is
caused by dirt , tapping the suspicious clogged point (generally in the capillary or the connection joint
of the filter) may cause the refrigerant to flow through partially, resulting in some corresponding change,
whereas in that case if you heat it with a hot towel, no reaction will happen, no flowing s ound can be
heard, moreover, there i s no periodi c change. Af ter rejecting t he possibility of ice clogging, it can be
generally considered as the clogging due to dirt .
REMEDY
Dismantle the system, remove the d ry filter from i t, purge the t ubing with nitrogen, install a new filter,
then evacuate it and finally charge it with refrigerant.
C) Clogging in filter
ANALYSIS OF TROUBLE
Total clogging of a filter is rarely to occur. This trouble is mostly caused by the paste-like matter formed
from the subst ances filled into the system or other dust af ter t he refriger ator has be en used for a

longer time, or by the dirt accumulated gradu ally inside the filter . Sometimes, tapping the filter na y
cause a passage for flowing, Touching it with your hand, you will feel that it is cooler compared with its
temperature in the normal state.
REMEDY
The same as described in the capillary clogging with dirt.
3) Troubles of Compressor
a) Breakage of gas suction and discharge valve blocks
ANALYSIS OF TROUBLE
The compressor works by means of the opening and closing of gas suction valve and discharge valve
to suck and discharge the refrige rant. If the valv e block is broken, the refriger ant can not b e
discharged, and hence no refrigerating can be achieved.
METHOD FOR MAKING JUDGEMENT
It is quite difficult to differentiate this trouble from others because they often have similar symptoms. In
repairing, fir stly, hear attentively if there is some abno rmal sound coming from the compressor
(sometimes , the broken pieces of valve block may strike against the cylinder), and feel th e
compressor casing with your hand to ascert ain whethe r it is too hot, this is also help ful to the
troubleshooting; secondly , meas ure the pressures at the high and lo w pressure port s of th e
compressor with pressure gauges, if the gas suction valve block is broken, the suction pressure gauge
pointer will swing violently and the suction pressu re is very high, wher eas when the gas discharge
valve block is broken , the discharge pressure ga uge pointer will swing drastically and the discharge
pressure is very hi gh. In the bot h cases, stop the compressor at once, and if technique is available,
open the cylinder cover and check up the valve block, repair it, or replace it with a new one.
C. Sudden stop of Compressor during Its Running
The cause of sudden stop of a compressor during its running is mostly that the gas suction pressur e
and/or discharge pr essure excee d their re spective pr escribed ra nges, thus making a
pressure-operated protective relay shut off the power to the compressor and stop it. In the following we
discuss mainly the r easons for causing excessive ly hig h gas discharge p ressure and low suction
pressure.
1) Stoppage due to excessively high gas discharge pressure
A) Too much refrigerant charged into the system
ANALYSIS OF TROUBLE
The pheno menon, such as loose frosting and poor re frigerating ef fect, may occur if excessive
refrigerant has been charged into the system. Su perfluous refrigerant will occupy a cert ain space of
the evapor ator, thus red uce it s heat dissip ating ar ea, an d the phen omenon of “liquid s triking” ma y
occur, too. Meanwhile, dew or frost condensati on may occur on the gas return tube, and the ga s
discharge pressure will obviously ri se, when it reaches the thr eshold value, the protective relay will
actuate and shut off the power supply to the compressor.
REMEDY
Open the tubing, re-evacuate and then charge the system with a proper quantity of refrigerant.
b) Air left in the system
ANALYSIS OF TROUBLE
The residual air in the system will circulate together with the refr igerant in the system. The major
symptoms caused by this residual air is hi gher gas discha rge pressur e, higher discharged ga s
temperature (the gas discharge tubing is considerably hot when you feel it with your hand), and poorer

refrigerating effect. Furthermore , the gas discharge pressure will exceed i ts normal value when the
compressor has run for a period not too long, thus making the protective relay actuate and bring to a
stoppage.
REMEDY
Check up how the air has been lef t in the refrigerat ing system. Generally, there are two possibilities:
one is that the air has b een sucked into the system when r epairing due to carelessness, or it has not
been purged out totally when evacuating the system; the other is that there are leak points at the low
pressure end of the refrigerating system. Leak points appear mostly in those low temperature parts or
assemblies, because the evapor ation tempera ture is lower for such low tempera ture devices ,
especially at the low pressure end, it is easier for the air goes into the system. Once it has been
ascertained that air does exist in the system, you have to o pen t he tubing, re-evacuate it and the n
charge it with refrigerant.
2) Stoppage due to electric troubles
a) Thermostat is out of control
ANALYSIS OF TROUBLE
In case the thermostat does not work in its good order or its temperature sensor has not been installed
properly, frequent stoppage is also likely to occur.
REMEDY
Try to adjust the temperature sensor’s position u ntil the co mpressor can be st arted and stopped
normally. If this cannot be achieved, and the stoppage still occurs repeatedly, it is most likely that the
mechanical parts or contacts are out of order, disassemble the thermostat, make a thorough checkup
and repair it.
b) Overload of electric motor
ANALYSIS OF TROUBLE
Probably, too many things have been put into the refrigerator, and hence the thermal load exceeds its
refrigerating cap acity ; or in ca se the power s upply volt age dr ops considerably, the current flowing
through the motor will increase drastically making t he thermal protector actuate and the fuse blown ,
and hence the motor stop s running. If the motor is still running continuously in such a case , it s
windings will be burned out .
REMEDY
Reduce the thermal load, pay attention to the variation in voltage of the power supply.
c) Abnormal thermal protection
ANALYSIS OF TROUBLE
The compressor current is within its normal range, but the thermal protector actuates repeatedly.
REMEDY
Replace the thermal protector with a new one.
3) Sudden stoppage due to other causes
NORMAL STOPPAGE
Start and stop of the compressor is generally controlled by a thermostat . When the temperature in the
refrigerator reaches it s d esired value, the thermost at will shut down the compressor automatically .
Never take this normal operation as a trouble, care s hould be taken to differentiate it fr om other rea l
troubles in servicing.
D. Compressor won 't start
In case the compressor cannot be started, you must find out the origins of this trouble through checkup