Function; System Operation Control - Technibel MPAFIA0R5IAA Service Manual

5.FUNCTION

5-1 System operation control

The inputs to the systems come from indoor and outdoor sensors. The outdoor unit is the system
MASTER while the indoor one is the SLAVE.
Communication between units is made with a 2 poles RS485 bus
The indoor units receives the user input (fan speed, flap position etc) through remote controller
which sends signal every time a button is pressed and in any case, automatically, every 5 minutes.
5.1.1 control specification
During operation compressor speed can be subjected to change due to thermal load variations
or protection activations but in any case:
• The minimum time interval between an OFF and a ON operation is not lower than 3 minutes
• The minimum operating time is not lower than 3 minutes
• The maximum acceleration/deceleration rate is fixed at 20rpm /sec
• During the start-up compressor speed increases according to a defined rule which is
independent from the thermal load calculation.
5-1.2 Multisplit available modes
If the unit is a part of a multisplit system, there could be some mode combination not available
(example: unit A - heat mode and unit B - cool mode).
In this case the system automatically stops, leds TMR and STB blink whilst led OPR is on
● = LED blinking
● = LED on
AUTO
HEAT
DRY
COOL
FAN
AVAILABLE MODE COMBINATION TABLE
AUTO HEAT
□ □
□ ■
□ □
□ □
□ ■
■
AVAILABLE
□
NOT AVAILABLE
INDOOR UNIT A
DRY COOL
□ □
□ □
■ ■
■ ■
■ ■
10
FAN
□
■
■
■
■