city multi V VRVIII questions questions

[multisync]

1 On a 30kw Mitsubishi does the outdoor have one or two compressors. If two can it run in emergency mode?

2 Can you multi them up to have 3 x 30kw and run 2 pipes down to 6 bs boxes

3 Does Mitsubishi have the 'self weighing' of charge like Daikin VRVIII

4 Will the allow shut off valves in the system unlike Daikin who won't warranty

5 Can you turn off one indoor unit and keep the rest running

Thanks



Multisync
London

[Thermatech]

30 kw nominal would be size 300.
Latest unit ref PURY-P300YHM-A
1/ One inverter compressor on all outdoor units up to size 400.
2/ Can double up outdoor units to make up to size 800 about 90kw nominal cooling.
No too sure about 6 BC boxes but lates product catalogue indicates 3 B/C boxes 1 master & 2 slaves.
All B/C boxes available up to 16 ports , so that at least 48 indoor unit connected to each set of outdoor units.
3/ No auto charging. Need to calculate trim charge & add in traditional method.
4/ Shut off valves not a problem as far as I know , you would need to check with Mitsubishi sales rep for confirmation on this point.
5/ Turn 240v power off to any indoor unit & all other units continue to operate normally , no problem no fault alarms.

[multisync]

2/ Can double up outdoor units to make up to size 800 about 90kw nominal cooling.

If we lose one compressor does the whole system go down?

3/ No auto charging. Need to calculate trim charge & add in traditional method.

Daikin assist F-Gas by this feature with self check. Will Mitsi do the same?

4/ Shut off valves not a problem as far as I know , you would need to check with Mitsubishi sales rep for confirmation on this point.

Will do

5/ Turn 240v power off to any indoor unit & all other units continue to operate normally , no problem no fault alarms.

Cool

Thanks Thermatech you are a star!

Multisync
london

[Thermatech]

2/ On double outdoor units emergency operation available from remote controller when fault with one of the outdoor units.
Up to 60% capacity indoor units operational in this case.
I have not tested this on the latest YHM-A models but there is afull page in the service maunal explaining emergency operation.
3/ ME cover F-gas with detailed trimcharge calculation page in commissioning logbook.
Outdoor unit also has 'refrigerant adjust mode' for service enginner to test if refrigerant charge is adequate.

[The Viking]

[B]Daikin assist F-Gas by this feature with self check.]

Having tried this "self charge" function, I would say that it is a sales gimmick!

In real life it doesn't work.
One system charged using this method showed clear symptoms of undercharge during commissioning, proper calculation of the additional charge required gave us a result almost twice of what the unit had sucked in by itself.

Another system needed reclaiming and an indoor unit relocated (consultant not speaking to customer?), during recommissioning the engineer recalculated the charge and found the system 5kg overcharged.

Nah, Humbug I'll say.

(Don't get me wrong, I do like the VRVIII but this function...)

[multisync]

Having tried this "self charge" function, I would say that it is a sales gimmick!

In real life it doesn't work.
One system charged using this method showed clear symptoms of undercharge during commissioning, proper calculation of the additional charge required gave us a result almost twice of what the unit had sucked in by itself.

Another system needed reclaiming and an indoor unit relocated (consultant not speaking to customer?), during recommissioning the engineer recalculated the charge and found the system 5kg overcharged.

Nah, Humbug I'll say.

(Don't get me wrong, I do like the VRVIII but this function...)

I agree with you there and would want to be doublely sure the right amount was added. But wonder if the self check works only if you let the system self charge rather than self charge + - what it should really have.

Multisync
london