INDOOR UNIT CONTROL CIRCUIT (Continued)

NO.

Item

Overview of specifications

Remarks

8

Freezing

(1) Performs the following operation control in the COOL or DRY

Tcj : Indoor unit heat

 

prevention control

mode according to the Tc (or Tcj) sensor detect temperature.

exchange sensor

 

(low-temp.

When zone J in the figure below is detected for 6 minutes, the

temp.

 

release)

specified operating frequency is decreased from the actual

 

 

 

operating frequency, and the specified operating frequency is

 

 

 

changed every 30 seconds in zone J.

 

 

 

 

Timer count stops and is maintained in zone K.

 

 

 

Timer count is cleared to restore normal operation when zone I is

 

 

 

detected.

 

 

 

 

 

If the specified operating frequency becomes SO due to

 

 

 

continuation of zone J, return temperature A is raised from 5 to

 

 

 

12 °C, and operation with L fan speed continues until zone I is

 

 

 

detected.

 

 

 

 

 

Tc(˚C)

 

 

 

 

 

5

I

A

 

 

 

 

 

K

 

 

 

2

 

 

 

 

 

 

J

 

 

 

 

If 4-way valve cannot be switched during heating and the following

Tcn :

 

 

conditions become true, freezing prevention control is performed.

Tc after 5 minutes

 

 

(However, zone J entering control temperature is changed from 2

from operation start

 

 

to -5 °C.)

 

 

Tc (n-1):

 

 

[Conditions]

 

 

Tc at operation start

 

 

The following A or B becomes true after 5 minutes pass from

 

 

 

operation start.

 

 

 

ATcn<=Tc(n–1)–5

BTcn<Tc(n–1)–1 and Tcn<=Ta<5°C

9

High-temp. release

(1) Performs the following operation control in the HEAT mode

 

 

 

control

according to the Tc (or Tcj) sensor detect temperature.

 

 

 

 

•

When zone M is detected, the specified operating frequency is

This control is disabled for

 

 

 

decreased from the actual operating frequency, and the specified

twin follower indoor units.

 

 

 

operating frequency is changed every 30 seconds in zone M.

 

 

 

•

The specified operating frequency is maintained in zone N.

 

 

 

•

When zone L is detected, the specified operating frequency is

 

 

 

 

returned by approx. 6 Hz every 60 seconds.

 

 

 

 

Factory setting

 

 

 

Tc

 

 

 

 

 

Control temp. (°C)

 

(˚C)

M

 

 

 

 

 

 

Tcj

 

 

 

 

 

 

 

 

A

 

 

 

 

 

A

B

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

N

 

 

 

 

 

56 (54)

52 (52)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

B

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

L

 

 

 

 

Note)

At the beginning of operation or when Tc (or Tcj) lowers below

Even when the thermo is

 

 

 

30 °C after operation start, values (54) and (52) in the table are

set to OFF, the control is

 

 

 

used as control temperature.

 

 

 

implemented in the same

 

 

 

 

 

 

 

 

 

 

way.

 

 

 

 

10

Residual heat

Runs indoor unit fan in L (low) mode for about 30 seconds after HEAT

 

 

removal

operation stops to remove residual heat.

 

 

 

 

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