To multisplit or not to multisplit

[Radian]

Got a couple of 3.5kW Daikin A2A air handlers being installed but the individual outdoor compressors are on a longish lead time. The installer recommended having a compressor for each unit rather than a single multisplit but I'm wondering what the issues are?

[pudding]

As long as the outdoor unit is rated as large enough to satisfy the indoor unit demands, then the only negative of having 1 rather than 2 outdoor units is that you wont be able to have 1 indoor unit heating and 1 cooling, they both need to be operating in the same mode. Apart from that, nothing, should be an easier install only needing one power supply.

 

I've got one outdoor Daikin unit feeding 3 indoor units, 2 x x2.5kw and one 3.5kW. All 2.5kW would have been fine but went with the 3.5kW as that was available in black. We would have been ok with 2kW units, and because of that the outdoor unit is only a 5/6kW (cant remember now) so we cant actually run all units full blast, but thats not a problem for us. There's a table in the Daikin manual that shows the combinations of outdoor and then number of different indoor units and what power you'd actually get from them.

Edited September 24, 2022 by pudding

[JohnMo]

There is a slight drop in performance for both SEER and SCoP, but nothing major on the multi split.

 

Two modes of operation to consider, all indoor units on at once or just one at a time. An example is installed in living room and bedroom, you may only on either or room not both at the same time, so in that case a small outdoor unit would be ok.  Installed in two bedrooms you would want a bigger outdoor unit to service both at the same time.

 

Single split, you get better overall performance)SEER and SCoP) but a few small units outsides, shorter piping runs that be may be easier to route and hide.  Outdoor unit sized for optimal performance in any room.

[Radian]

17 minutes ago, JohnMo said:

shorter piping runs

Yes I think that might be a significant factor in the planned system design. There's a long outside wall (thankfully a gated-off 12m dead end corridor behind of our garage) where the compressors will be but the indoor units will be well separated with one on the ground floor and the other at the far end of the upstairs room. This means two separate compressors can be located close to their respective indoor unit.

 

Also, the upstairs is a room-in-roof office which gets very hot in the summer and shoulder months like now but the downstairs can be significantly cooler so I can envisage using a little bit of heating downstairs at the same time as cooling upstairs. Although the intention is to only use PV for cooling.

[TonyT]

2 hours ago, Radian said:

Got a couple of 3.5kW Daikin A2A air handlers being installed but the individual outdoor compressors are on a longish lead time. The installer recommended having a compressor for each unit rather than a single multisplit but I'm wondering what the issues are?

I think that’s the way I would go too

[Radian]

Daikin appear to have a 12 year warranty which is no doubt dependent on an approved installer performing regular maintenance - I haven't asked the installer about that yet as I was keen to get things moving before the colder weather sets in. Does anyone know what kind of surprises I might be in for?

[markocosic]

Vacuum / hose out the dust and wildlife; job done.

 

Units used for getting that condense on the outdoor coils stay a little cleaner.

 

Single outdoor unit to single head more efficient and flexible at expense of clutter.