# How do multi-zone ductless mini splits achieve multiple circuits, heads?

• 06-26-2013, 11:28 PM
georgelass
How do multi-zone ductless mini splits achieve multiple circuits, heads?
My google and search skills are not turning up anything about how these
things work in regards to multiple heads. I'm thinking they don't
have a compressor for each head/circuit, but I have no idea how they
achieve that? Maybe they have one motor and multiple compressing
pumps? Scroll of some sort or what? I'm simply very curious as I had
These things were 30 years old. Sanyo. Two of them are working just
fine still. The one is low on refrigerant. A fast leak, evidently as it was
cooling fine just a week ago. But I don't care about these units--so if
anybody asks me about pressures and ambient and airflow (!), I SWEAR
I'm going to slit my wrists. :) )

My questions and interests are just about DMS in general.
Thank you.
• 06-26-2013, 11:37 PM
jtrammel
Inverter drive compressor
• 06-26-2013, 11:42 PM
georgelass
Oh, of course.

(Waiting for kindly elaboration......or a link or something. Thank you.)
• 06-26-2013, 11:47 PM
georgelass

Sounds like a variable speed motor.
But I'm really asking about the pumping of refrigerant with multiple circuits.
• 06-26-2013, 11:50 PM
jtrammel
The compressor varies its capacity from ~30% to 100+% depending on how many heads are calling and how many degrees its trying to cool down to.
• 06-27-2013, 12:24 AM
georgelass
But the circuits cannot all be flowing the same refrigerant. They must be separate.
How is that accomplished? A diagram would be good.

Thank you.
• 06-27-2013, 01:39 AM
CraziFuzzy
Quote:

Originally Posted by georgelass
But the circuits cannot all be flowing the same refrigerant. They must be separate.
How is that accomplished? A diagram would be good.

Thank you.

single compressor, single condenser, then it splits to the three different evaporators, each with a solenoid valve to turn flow on and off to that loop. variable speed compressor to maintain proper head pressures with any given situation.
• 06-27-2013, 08:28 AM
craig1
I believe all the multi zone units it's use electronic expansion valves. The valves is able to shut 100% when you turn a specific zone off.
• 06-27-2013, 09:04 PM
smokeater2025
look up mitzubechi MR. slim spelling not correct we have put several in work great.
• 06-28-2013, 02:15 PM
monkeyspanners
Some of the older units (Fujitsu i think) didn't use an inverter comp, some had two comps and four circuits (two separate twin circuits) but kept refrigerant running through the idle unit. Most times it was ok but a few time ive seen where people have put one unit in a server room and the other one would sweat as it was in an unused office.