fujitsu multi split, how it works??

hello
i am a commercial refrigeration engineer so please be gentle!!

my office has just had a new fujitsu multi split fitted and i have a couple of questions if anyone could please help


fujitsu multi split 3 x indoor units and one outdoor unit with 3 sets of 3/8 pipes from the unit to each coil and one compressor

1. all pipe runs are of diffrent lengths so how will it ensure correct flow of refrigerant to each

2. if one indoor unit is switched off what will the outdoor system then do

3. is there any drawbacks to this type of system

thanks

steve

little bump

I see it so.
If all inside units are switched off, all solenoid valves are off, compressor is off.

If at least one unit is on, compressor slowly starts, the corresponding solenoid valve opens, compressor begins pumping the refrigerant in the corresponding unit's circuit adjusting its speed, thus pressure(s), thus temperature(s) to satisfy the temperature demand at the corresponding unit's premises.

If the second unit is on, then the third one is on, their solenoids are on, compressor's speed increases, etc, etc, to satisfy the increased demand for air temperature.

The demand at all premises being satisfied, compr slowing down, then stops. What do the solenoids at that time, I dont know.

All the units off, all solenoids off.
Only one mode is possible - if one inside unit is set to cooling, for instance, it is impossible to set an other unit for heating.

so this type of systejm could only be used with a vari speed compressor.
that makes a lot of sense now, thanks for that

Invertor, or frequency converter.

thanks for that

Also, some multisplits may use electronic flow control valves to regulate the gas flow.

hello brian, so how would an electronic flow control valve work i.e. what would control it

thanks
steve

Probably by monitoring the pipe temperatures.

Fujitsu units use a series of Fujikoki electronic expansion valves usually 1 main valve & 1 for each head. No solenoid valves. The set starting point for each valve is pre- programmed & various sensors let the controller know what setting is needed for each valve. the valves do not shut fully but are 10% open even when the head is off.