FILE NO. SVM-07008

Item

Operation flow and applicable data, etc.

6.Defrost control (This function removes frost adhered to the outdoor (Only in heating heat exchanger.)

operation)

The temperature sensor of the outdoor heat ex-

 

 

changer (Te sensor) judges the frosting status of the

 

outdoor heat exchanger and the defrost operation is

 

performed with 4-way valve reverse defrost system.

 

Start of heating operation

 

 

 

 

temperature

 

 

 

 

 

 

 

 

 

Operation time

0’

10’ 15’

27’40”

34’

 

(Minute)

exchanger

–5˚C

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

C zone

–7˚C

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

heat

 

 

 

 

 

 

 

A zone

 

 

 

 

 

 

 

 

–20˚C

 

 

 

 

 

 

 

 

 

 

Outdoor

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

B zone

 

 

 

 

 

 

 

 

 

 

 

*

 

 

 

 

 

 

 

 

 

 

 

 

 

 

* The minimum value of Te sensor 10 to 15 minutes after start of operation is stored in memory as Te0.

 

Table 1

 

 

A zone

When Te0 - TE ≥ 2.5 continued for 2 minutes in A zone,

defrost operation starts.

 

 

 

B zone

When the operation continued for 2 minutes in B zone,

defrost operation starts.

 

 

 

C zone

When Te0 - TE ≥ 3 continued for 2 minutes in C zone,

defrost operation starts.

 

 

 

Description

The necessity of defrost operation is detected by the outdoor heat exchanger temperature. The conditions to detect the necessity of defrost operation differ in A, B, or C zone each. (Table 1)

<Defrost operation>

• Defrost operation in A to C zones

1)Stop operation of the compressor for 20 seconds.

2)Invert (OFF) 4-way valve 10 seconds after stop of the compressor.

3)The outdoor fan stops at the same time when the compressor stops.

4)When temperature of the indoor heat exchanger becomes 38°C or lower, stop the indoor fan.

<Finish of defrost operation>

•Returning conditions from defrost operation to heating operation

1)Temperature of outdoor heat exchanger rises to +8°C or higher.

2)Temperature of outdoor heat exchanger is kept at +5°C or higher for 80 seconds.

3)Defrost operation continues for 15 minutes.

<Returning from defrost operation>

1)Stop operation of the compressor for approx. 50 seconds.

2)Invert (ON) 4-way valve approx. 40 seconds after stop of the compressor.

3)The outdoor fan starts rotating at the same time when the compressor starts.

– 32 –