Daikin Heat Pump- Monoblock or Split System??

bauney

Hi,
I'm building a house and i know what heating system i want for my underfloor system.
I am going for a Aerothermal heatpump. I have been recommended to use the Daikin brand of heatpump.
However, after researching it, i see that there are 2 types of Daikin heat pump - (i) The Monobloc and (ii) the Spilt System.

In my mind (no previous experience in plumbing/heatpumps) the Monobloc looks like the more advanced system as it comprises of 1 outdoor unit as supposed to the Split System which has both an outdoor and indoor unit.Not much difference in the price.

I've asked around and the Monobloc appears to be the preferred one. However my plumber thinks the split system is the better one but i'm not sure.

Can someone who has any experience please let me know or what you think?
Thanks,B

Do-more

The main disadvantage of the monoblock outdoor unit is that you have water in the pipes running out to it rather than refrigerant in the pipes to the outdoor unit in the split system.

The only time this causes a problem is if you have a long power cut during freezing weather and the water in the monoblock freezes and destroys it. (Likewise you couldn't go for a fortnight in the Caribbean and leave the heat pump switched off for the same reason )

It's up to you to make the call on how likely that is to happen and if it does is it covered by your house insurance?

This cannot happen with the split system which also has the advantage that there are less components "out in the weather" so it's (debate-ably) likely to last longer.

The disadvantage of the split system is that the compressor is indoors which can be noisy so you need to be careful about sound insulating the room it is in.

[Edit] I just had a look for the technical specs of the two different types and their website is a nightmare to navigate all based on different product codes without descriptions, I would suggest that, before making your choice, you also look at the technical data for the two specific models you are considering to check if there is a significant difference in performance or not.

bauney

Thanks DoMore. According to my plumber the split system has a slightly better COP / performance. Also, the split system is used in colder climates such as the scandic countries, whereas the monobloc is used in milder climates such as uk and ireland.
According to some independent opinion from Daikin Dublin, they say that 90% of systems installed are Monoblocs and the remaining are split systems. Does that make the Monobloc the best one or is it just the most convienent?

I want the most stable and best performing system e.g. one that is easy to maintain and is less likely to cause me problems (and if it does can be easily fixed/replaced). My plumber thinks this is the split system. So maybe i should just go with it as he will be the guy who will be fixing it if needs be.

Any more advice would be helpful.
thanks

al2009

Do more

The compressor for the split system is still outdoors, unless you are thinking of the high temp version which has a small boost compressor internally (in a well sound proofed box).

B

Your plumber may not be able to install the split system as it is a refrigeration installation, ~(unless they are certified), you can contact Daikin for installers or depending on your location i can recommend one for you.

I can put you in touch with someone who has spec'd and installed many of these installs if you wish.

Alec

bauney

Yes please PM me the contact. Thnks

Do-more

al2009 would you also be good enough to comment on whether it is advisable to have a buffer vessel in the UFH system when using an inverter heat pump.

I see a lot of conflicting advise about this, some saying you should and others advising that its not required.

I'm not sure if it was on this forum or another but I recently read a comment saying that many compressors have failed in the last 5 years due to having insufficient water quantity in the UFH circuits for the defrosting operation.

In my own case I am looking at a different brand of inverter HP and my UFH pipework only contains about 50 litres of water. The installer says that it doesn't need a buffer vessel and the HP is covered by a 6 year insurance from the supplier so I probably shouldn't be worried, but I am still not fully convinced!

al2009

Do more

i don't profess to be a UFH expert, i would imagine that if there is sufficient water in the circuit a buffer may not be necessary, low water volumes lead to excessive compressor cycling, this will kill the compressor no problem. Maybe others on the forum can comment better though. BTW a 6 year warranty is excellent, it should give you peace of mind alright!

alec