Air conditioner--Refrigerant

z

The pressure of high and low
pressure end is low.

z

The pipeline from condenser
to expansion valve frosts.

z

Refrigerant flow in adjuster
is obstructed by impurity.

z

Change the condenser.

z

Adjuster is obstructed.

Phenomenon

Possible reason

Diagnose

Method

State: cooling degree is not enough

(4) Refrigerant cycle is poor

(5) Refrigerant does not have any cycle.

z

Low pressure side is

vacuum, and pressure at

high pressure side is low.

z

The pipeline of front and

rear end of expansion

valve or adjuster frosts or

dews.

z

Refrigerant flow in cool-

ing system is obstructed

by water vapor or dust.

z

Refrigerant flow is ob-

structed by expansion

valve.

(1)Check the expansion

valve.

(2)Remove the dirt in ex-

pansion valve with high

pressure air.

(3)Change condenser.

(4)Take out vacuum and fill

applicable refrigerant.

(5)If this is caused by ex-

pansion valve leakage,

change the valve.

Refrigerant does not flow.

Phenomenon

Possible reason

Diagnose

Method

 State: not cool (sometime cool)

 217 

Air conditioner--Refrigerant

z

The pressure of high and

low pressure end is high.

z

There is no bubble on

window when engine

speed decreases.

z

Too much refrigerant in

system incurs this.

z

Heat dispersion of con-

denser is bad.

(1)Clean the condenser.

(2)Check the function of

cooling fan.

(3)If those two items above

are normal, check the re-

frigerant quantity. Fill

applicable refrigerant.

z

Filled refrigerant is too

much.

z

Heat dispersion of con-

denser is bad ¡ú

¡ú

¡ú

¡ú

¡ú

heat dis-

persion sheet of con-

denser is obstructed or fan

engine has malfunction.

Phenomenon

Possible reason

Diagnose

Method

State: cooling degree is not enough.

z

The pressure of high and
low pressure end is high.

z

Pipeline of low pressure
end is too hot to contact.

z

T h e r e   i s   b u b b l e   o n
window.

Air enters cooling system.

(1)Check whether the Re-

frigerant oil is too dirt or

lack.

(2)Take our vacuum and fill

new refrigerant.

z

There is air in cooling

system.

z

I t   d o e s   n o t   t a k e   o u t

vacuum completely.

Phenomenon

Possible reason

Diagnose

Method

State: cooling degree is not enough.

(6) Refrigerant is too much or the radiating fin of condenser is bad

(7) Air enters cooling system

Note: if  cooling system is

opened, and it does not

take out vacuum when

filling refrigerant, this

state will happen.

 218 

Air conditioner--Refrigerant

z The pressure of high and low

pressure end is high.

z Pipeline of low pressure end

frosts or dews heavily.

E x p a n s i o n   v a l v e   h a s

malfunction.

Check the expansion valve.

z Refrigerant in low pressure

pipeline is too much.

z Open degree of expansion

valve is too big.

Phenomenon

Possible reason

Diagnose

Method

State: cooling degree is not enough

z The pressure of low pressure

end is too high.

z The pressure of high pres-

sure end is too low.

There is inner leakage in

compressor.

R e p a i r   o r   c h a n g e   t h e

compressor.

z Compressor is bad.
z Expansion valve leaks or

sliding part is damaged.

Phenomenon

Possible reason

Diagnose

Method

State: not cool

(8) Expansion valve is bad

(9) Not cool

 219 

Air conditioner--Refrigerant

Reading of filling meter (referred value)

 220 

Pressure of low pressure side

Fan “HI” phase

Blower “LO” phase

Pressure of high
pressure side