Am I doing the right thing before I give the go ahead:

[back2space]

Hello guys, just looking for a little support on this matter. As you know my system is being replaced and I have been given two different quotes, Multi Split or separate systems. Am I doing the right thing going for the separate systems? I know I can use the auto change over function and have diff rooms in heating/cooling on separates if required.

Equipment suggestions as follows; This is for Mitsi M Series: Separates works out cheaper than Multi.

Separate Splits:

2 X SUZ-KA35VA (OUTDOOR UNITS 3.5KW)
2 X MFZ-KA35VA (INDOOR FLOOR MOUNTED UNITS 3.5KW)

1 X MUZ-FD35VAH (OUTDOOR UNIT 3.5KW)
1 X MSZ-FD35VA (HIGH COP INVERTER WALL MOUNTED UNIT 3.5KW)


Multi Split:

1 X MXZ-4A80VA (OUTDOOR UNIT 8KW)

2 X MFZ-KA35VA (FLOOR MOUNTED UNITS 3.5KW)

1 X MSZ-FD35VA (DELUXE WALL MOUNTED UNIT 3.5KW)




Worried about Maintenance costs also, for instance if compressors go after the warranty on two systems then I assume its more expensive than just fixing a multisplit unit


Been given running specs so I can see just how much each system should use and what the multi would use: Seems cheaper to run one split system rather than the multi if I only want one indoor unit operating. However uses more wattage if all three are running flat out wheareas multi comes in less if all 3 are running.

Separate splits: Can ramp down more thus producing even less capacity if need be.


Capacity - Cooling (min. - max.): 0.9 - 3.9 kW
·
Capacity - Heating (min. - max.): 0.9 - 6.2 kW
·
Power input - Cooling (min. - max.): 0.19 - 1.25 kW
·
Power input - Heating : 0.19 - 2.24 kW


Multisplit: Specs for 1,2 & 3 unit operation: To have one unit operating uses more than if one was operating.


1. Capacity - Cooling (min. - max.): 3.5 (1.5 - 4.3)
·
Capacity - Heating (min. - max.): 4.0 (1.2 - 4.8)
·
Power input - Cooling (min. - max.): 1.030 (0.400 - 1.290)
·
Power input - Heating : 1.210 (0.330 - 1.570)

2. Capacity - Cooling (min. - max.): 7.0 (2.0 - 7.1)
·
Capacity - Heating (min. - max.): 8.0 (1.8 - 9.8)
·
Power input - Cooling (min. - max.): (0.540 - 2.550)
·
Power input - Heating : 2.370 (0.480 - 3.230)


3. Capacity - Cooling (min. - max.): 7.95 (2.9 - 9.0)
·
Capacity - Heating (min. - max.): 9.4 (2.6 - 11.6)
Power input - Cooling (min. - max.): 2.280 (0.720 - 2.910)
·
Power input - Heating : 2.170 (0.530 - 3.380)


If you dont mind, what is your opinions on all of the above. Aesthetics are not a problem etc. I am spending a lot more this time than the LG and want to make sure the overall solution is perfect.

Installer reckons multisplit but this comes out at £450 more than separate splits, he says over the long run it will work out cheaper for me???? Confused.com now!

[nike123]

If aesthetic is not problem go with separate units.

I don't see how maintenance and repair could be higher on separate units than on multisplit unit.
Also, instalation cost of two separate systems should be less if they are placed separate, close to indoor units.

[back2space]

I don't see how maintenance and repair could be higher on separate units than on multisplit unit.
.

Because for instance if compressor goes on one separate unit then it may also go on another unit at later date meaning more repairs as each system ages and 3 outdoor units to maintain whereas only one with multi.

With multisplit if compressor goes you only replace it once as shouldnt fail on same unit but then compressor may fail on another system at later date.

[Greengrocer]

The indoor units quoted are the same for both the separate splits and the Multi systems so that shouldn’t be a factor. “Apples for Apples” – that assumes you’re happy with the aesthetics and sound levels of the proposed units.
The only real reasons for considering a Multi over separate splits under normal circumstances are:-
·Space. If you have restricted outdoor space then a single Multi outdoor unit is more compact and only needs 1 wall bracket, set of pads or paving slab to sit on. 3 separate splits will need 3 of everything and more physical space. However, being separate you can move the outdoor units nearer the indoor units which reduces the amount of interconnecting pipe-work & cabling so this should save cost vs a multi which would have longer pipe runs.
·Power supply. The Multi system only needs a single power supply (25amp) to the outdoor unit. The indoor units get their power from the Multi outdoor unit which is run with the frig pipes. 3 separate splits need 3 separate power supplies (16amp each) and 3 separate breakers on your consumer unit. If you don’t have enough spare ways on your consumer unit then you need to upgrade the consumer unit for one with more ways or install a piggy back extension board – which means extra cost. If replacing the entire board it also means all the power to the house will be off for a period of time while the old consumer unit is taken out.
Some other factors might be:-
·Noise levels. 3 x split outdoor units at full tilt will have a higher sound level than a single Multi however both types are pretty quiet.
·Resilience. If the compressor in a Multi goes you’ve lost all cooling / heating. If a compressor goes in 1 split the others are unaffected.
·Servicing / maintenance. The cost difference for maintaining 3 separate splits and a 3 indoor Multi should be the same. Most companies price the maintenance based on the number of indoor units which in both cases is 3.
·Cooling / heating Capacities. You will get more cooling / heating out of the separate splits than the Multi. The splits are rated at 3.45kW cooling & 3.3kW heating at UK conditions. The multi indoor units will only produce 2.65kW cooling & 3.13kW heating maximum. So the splits will give you 0.8kW more of cooling capacity each than the Multi.
At the end of the day it is the physical aspects of most jobs that determine what type of equipment (splits or Multi) can be used. If both are feasible then normally it’s the cost or features that determines which is selected. Personally I would go for 3 separate splits. More flexible, individual room by room temp / mode control and & if one packs up the others can still run.

[back2space]

Thank you ever so much for taking th time to post that, yes I think I am going to go for the separate splits.

I was unsure as its nice to know all ur indoors are run off one outdoor unit rather than having separate systems but I like the fact I will be able to have them in different operating modes and use the autochangeover mode on the separate systems.

[back2space]

Another worry with the Multisystems is the EEV being slightly open in heating on the LG multi it still lets a lot of refrigerant through on units that are thermo off, enough to keep the fan blowing air at 43C heating the room to unconfortable levels. No one at mitsi can advise if the air will blow out hot enough to raise the temp on units that are thermo off but do say it could still be a problem as they do circulate refrigerant to coils that are thermo off also.

[multisync]

Mitsi recommend 6a for their 3.5kw splits.(running 3.9a max) There is absolutely no need for a 16a and should be positively avoided.. http://www.mitsubishi-aircon.co.uk/d...00000000215286

The 8kw running amps is 9.12a We would be more than happy to put this on a 16a supply.

Oversizing fuse ratings is unnecessary and causes undue expense for no benefit or protection.

[back2space]

Dont suppose anyone can get me any operating manuals for the high cop inverter unit can they?

[back2space]

Mitsi recommend 6a for their 3.5kw splits.(running 3.9a max) There is absolutely no need for a 16a and should be positively avoided.. http://www.mitsubishi-aircon.co.uk/d...00000000215286

The 8kw running amps is 9.12a We would be more than happy to put this on a 16a supply.

Oversizing fuse ratings is unnecessary and causes undue expense for no benefit or protection.

Multisync I clicked that link and under specs it says

Fuse Rating (BS88) - HRC (A)16

What does this mean?

[Greengrocer]

The 6amp rating is for the indoor unit only. 16amp is for the whole system back at the dis board / breaker.

[Greengrocer]

Dont suppose anyone can get me any operating manuals for the high cop inverter unit can they?

Your installer should be able to let you have them. Alternatively go onto the Mitsi web site, register and get into the tech download section. I can't at present cos I've forgotton my password. Files can be quite large.

[back2space]

Your installer should be able to let you have them. Alternatively go onto the Mitsi web site, register and get into the tech download section. I can't at present cos I've forgotton my password. Files can be quite large.

Ive tried to register but I doubt they will let me as im not an installer or distributor so not sure what to do.

Not got them installed yet just wanted to see what the instructions looked like etc.

[Greengrocer]

Multisync I clicked that link and under specs it says

Fuse Rating (BS88) - HRC (A)16

What does this mean?

BS88 is a British Standard spec

HRC if I remeber correctly is High Rupture Capacity fuse

(A) 16 = 16amps which is the capacity of the Fuse / MCB

HRC type fuses are not normally used much since most modern consumer units use re-setable miniture circuit breakers (MCB's). In which case they should be 16amp. Ask your electricain not to put the MCB's for the AC system on the earth leakaage protected side of the consumer unit or you may get nuisance trips.
Some Inverter systems leak to earth (normal) which trips the over sensitive earth leakage breaker. Had this problem before on some Daikin units we installed in a house.

[Greengrocer]

Ive tried to register but I doubt they will let me as im not an installer or distributor so not sure what to do.

Not got them installed yet just wanted to see what the instructions looked like etc.

They send you a password via email.
There is one other option. Find someone who's got a Mitsubishi 2008 Technical CDROM. The Hi COP High wall system service, install and operation manuals should be on it under the M Series section (as well as all the Multi info). Unfortunately I gave mine away to a customer a few months ago so can't help.

[multisync]

The 6amp rating is for the indoor unit only. 16amp is for the whole system back at the dis board / breaker.

Yep my bad but there's still no way I would put a system with a FLA of 3.9 inverter on a 16a supply. I would still use a 10a or evan a 6a. 16a is madness as all you are protecting is a big cable..

It is really bad that some manufacturers (and engineers by default) still hang on to the old fixed speed compressor fuse ratings. This is not good practice..

MIH agree with me at least -

5kw unit =10a fuse!

http://www.cooltechairconditioning.c...p?productId=18

[nike123]

Yep my bad but there's still no way I would put a system with a FLA of 3.9 inverter on a 16a supply. I would still use a 10a or evan a 6a. 16a is madness as all you are protecting is a big cable..

It is really bad that some manufacturers (and engineers by default) still hang on to the old fixed speed compressor fuse ratings. This is not good practice..

MIH agree with me at least -

5kw unit =10a fuse!



http://www.cooltechairconditioning.c...p?productId=18

As I said many times earlier, function of fuse in domestic instalation is to protect cable from overload, not to protect equipment, and there is nothing wrong with connecting equipment of 2A consumption on fused cable of 2 million amperes ( that example is for demonstration purpose).
You have same thing when you connect your mobile battery charger in socket on the wall. Would you change that fuse with one of 0,02A because that is current range of that charger?
Equipment should have (and it has, if needed) their dedicated protection.
Fuse in distribution board is determined by cable size which it feeds.

[Brian_UK]

Dont suppose anyone can get me any operating manuals for the high cop inverter unit can they?

Misti's UK site is down at the moment, found a Polish site with a user manual to give you a start
http://www.mitsubishi-electric.pl/do...G79F181H01.pdf

I'll keep looking.....

[R1976]

I wpold just like to say......

I also wonder why such high fuse ratings are given by manufacturers. I commissioned 2 Daikin 3.5kW units today and the running amps did not go over 1.6A. A 10A fuse is recommended but even this seems high. I ran them off a tempory extension lead and the electrician was talking about putting 4 mm cables in Why?

Also, has anyone had any problems wiring into ring mains?

[back2space]

Misti's UK site is down at the moment, found a Polish site with a user manual to give you a start
http://www.mitsubishi-electric.pl/do...G79F181H01.pdf

I'll keep looking.....

You guys are fantastic and thank you once again Brian for the link.

It would be good if you could thank someone each time you found a post useful as it wont let me thank you again as thanked on a previous post.

I have requested a password etc on mitsi site as we do facilities management so have put companies name down also.

DO you think they will approve?

[back2space]

What are everyone elses thoughts on the multisplit vs the separate splits and running costs etc?

[Greengrocer]

Yep my bad but there's still no way I would put a system with a FLA of 3.9 inverter on a 16a supply. I would still use a 10a or evan a 6a. 16a is madness as all you are protecting is a big cable..

It is really bad that some manufacturers (and engineers by default) still hang on to the old fixed speed compressor fuse ratings. This is not good practice..

MIH agree with me at least -

5kw unit =10a fuse!

http://www.cooltechairconditioning.c...p?productId=18

I agree. Fujitsu 3.5kW wall mount inverter = 10amp recommended fuse size.

However, in my Mitsi book it also states for the 3.5kW FD high wall
"system running current (A) Heating / Cooling [MAX] = 3.9/ 3.8 [10.5]".

Also note that this "nominal" 3.5kW unit has a variable heating capacity rating of 1.3 to 7.7kW . The 7.7kW would occur in mild ambient temps on over boost when the compressor would pull its highest amperage. Perhaps the reason for the recommended 16amp fuse?
Good stuff Eh?

[Brian_UK]

Found a Service Manual for the MUZ, haven't read but here's the link, 4.6MB pdf

http://ehem.sm4wdq.com/rrd/msz-fd25v...ual_utedel.pdf

I think this one is a Scandinavian site.

DO you think they will approve?

Oh yeah, they'll let anyone in

[Greengrocer]

You guys are fantastic and thank you once again Brian for the link.

It would be good if you could thank someone each time you found a post useful as it wont let me thank you again as thanked on a previous post.

I have requested a password etc on mitsi site as we do facilities management so have put companies name down also.

DO you think they will approve?

Why not. They, like everyone else at the moment, need as much business as they can get! BTW if you want to thank me click my rep power. If you don't know how just search on "rep power" there's a few threads on the subject.

[back2space]

BTW if you want to thank me click my rep power. If you don't know how just search on "rep power" there's a few threads on the subject.

I have clicked the scales and it just says I have already given it to you and to spread some rep about before giving it to you again... so I cant thank you more than once it seems

[back2space]

Found a Service Manual for the MUZ, haven't read but here's the link, 4.6MB pdf

http://ehem.sm4wdq.com/rrd/msz-fd25v...ual_utedel.pdf

I think this one is a Scandinavian site.

Oh yeah, they'll let anyone in

Excellent.

Cant seem to find out what the indoor unit does when it reaches thermostat off in heating, if it cant ramp down any further and the o/d goes off.

Does the fan go to very low and louvres point back up on the wall mounts to stop drafts but still allowing it to keep airflow over the return air sensor?

Regards
Richard.

[dougheret0]

IMHO op manuals are a necessity for variable speed (inverter controlled) air handlers. Make them a condition of purchase, including the installation manuals for the thermo/humicistat, which they also will resist letting you have. They will want to leave you with the user's manual, which tells nothing about programming, only which buttons to press.

[back2space]

Yeh I have managed to get the microprocessor control strategy from mitsi website so I understand how it performs.

I am impressed, just waiting for install date from installer as he is wanting to get the LG equip into someone elses premises and is selling as nearlly new unit which is correct.

[Brian_UK]

I am impressed, just waiting for install date from installer as he is wanting to get the LG equip into someone elses premises and is selling as nearlly new unit which is correct.

Psst, want to buy a slightly used AC, Life's Good mate; prices about to go up so get it now; cheaper than Ebay.
[sorry, couldn't resist]

[back2space]

Brian!!! We will have less of that! U was having a go at me the other week for turning the thread into a LG hatred thread!!! TUT TUT!

I think he wants someone to put it in their conservatory as will be perfect for that application. Anywhere however where you want temperature control etc then dont bother looking at lg! U would be better off with a fan heater or portable air con unit!!

[sinewave]

LG - Lifes Garbage!

[Brian_UK]

OK guys, I stand corrected; nuff said.

Next subject please

[back2space]

U started it Brian haha

[olddog]

Sorry to pull up this oldish thread.

I was looking for user views on the Mitsi MFZ floor standing range and search brought up this thread.

Back2space, did you go ahead with this project ? If so how do you find the MFZs compared to wall mount units. ?

BTW Has anyone tried locating wall mount units low down on the wall where the application is heating ?

Anyone notice what seems like an anomoly in the Mitsi 4A80 figures

With two 35 class indoor units :

Capacity - Cooling (min. - max.): 7.0 (2.0 - 7.1)
·
Capacity - Heating (min. - max.): 8.0 (1.8 - 9.8)
·
Power input - Cooling (min. - max.): (0.540 - 2.550)
·
Power input - Heating : 2.370 (0.480 - 3.230)


With three 35 class indoor units :

Capacity - Cooling (min. - max.): 7.95 (2.9 - 9.0)
·
Capacity - Heating (min. - max.): 9.4 (2.6 - 11.6)
Power input - Cooling (min. - max.): 2.280 (0.720 - 2.910)
·
Power input - Heating : 2.170 (0.530 - 3.380)


Looks like they are much more efficient when hooked up to three indoor units then two !

( looking at the data book it seems the 4A80 is even more efficient when hooked up to 4 indoor units )

Olddog

[al]

OD

I've a Hitachi floor mount in the house and fitted a Fugitsu to a house in Wicklow last week, both are excellent for heating, there is a thread here on high walls mounted down low.

Al

[back2space]

Hi there

I didnt go ahead with the system, however in my next house that will be the sort of thing I have installed and will be brand name equipment. I think I personally would go for separate splits rather than a multi though next time.

What I like about the floor mounts is that they have an louvre that directs heat at feet level so keep your feet warm... other manufacturers also do this model including MHI and Daikin.

Nope there is no anomaly in the figures, multisplit units perform better and more efficient the more units that are connected... the reason for this is that you have a larger compressor that is sized to run the max number of units, so if you dont have max number connected there are certain ranges that the compressor can down turn to, eg if only 1 unit is operating the lowest it might be able to ramp down to might still be higher than the actual than the heat output that is required in the room.

The more units that are connected the outdoor unit is more in design limits so its best to have as many units in operation at any one time as you can to get max efficiency from the unit.

I find that if I have only one indoor unit with my lg multi system running that it uses more power than if I had two running and ramped down.

Again the reason is due to the larger compressor and condenser coils etc.

[olddog]

Al, Back2space thanks for your replies

Al, Thread 21386 ?

Looks like the cosmic rays are at work again !



Back2space, yup thats the reason alright. Perhaps I should have said counterintuitive rather than an anomoly ?

Olddog

[back2space]

what are you going for then?

[olddog]

what are you going for then?

Will be meeting with the customer in a couple of days - so we will see.

No room for a lot of outdoor units so expect that will have to be a multisplit.

Guess low mounted wall units and some sort of 'radiator cabinet' enclosure would come out the same sort of cost as a floor unit - but might look more normal ?

[back2space]

Will be meeting with the customer in a couple of days - so we will see.

No room for a lot of outdoor units so expect that will have to be a multisplit.

Guess low mounted wall units and some sort of 'radiator cabinet' enclosure would come out the same sort of cost as a floor unit - but might look more normal ?

If your going to use wall mount units you need to mount these at the height there supposed to be at.

On heating you may find that they direct the air literally at 90c towards the floor you will probably find that they start short cycling the hot air back into the units.

On cooling the air flow is directed across from the unit and if these are not mounted near the top of the wall you will find that cold air is blown directly at you and the cold air will not circulate in the correct pattern.

If you go for wall mounts ensure you mount them at the proper height.

I have two lg floor mount units and 1 wall mount unit.

The wall mount unit controls the temperature in the room better and this is with it mounted near the top of the wall.

You will find that using them like this will lead to control problems and comfort problems with air flow being directed directly at people or not circulating properly.

THe floor mount units in cooling direct the air flow up into the room kind of like a radiator would, the cold air then blanket falls from the ceiling.

In heating the air flow is directed at a 45C angle.

The wall mount in heating directs air down at 90c to the floor and in cooling direct it across the length of the ceiling.

Using them in any other way you will end up with problems as to how the louvres point down.

I would consider the LG multi split again but would probably just go for wall mount units as whilst they are cheaper to buy for a start they have more features built into them than the floor mounts.

All the problems I had with my system were down to the incompetent installers who for the last year had led me to believe it was the lg equipment at fault.

Since the recharge with refrigerant no problems at all in fact my flat mate says he gets too hot now... turns out he is operating the unit with the emergency on/off button on the front, which defaults to heating 24C or cooling 22C!

Then denied messing with it when I said you shouldnt be using the emergency button! I dont want him messing with the remote as he will turn it on heating 30C like anyone does who dont understand heating systems.

[al]

Now Ye're talking!

Al

[back2space]

Now Ye're talking!

Al

How do you mean?

[al]

Cross forum chatter, just ignore us! Good to see the splits are finally working!

al