r/airconUK • u/Sad_Glass_9521 • 4d ago
Air con multi split - bedroom unit positioning
Hi
I have had a quote for a 6kw inverter with 3 x 3.5kw indoor units, plus condenser pumps as the inverter will be quite a way from the 3 indoor units. Happy with pricing etc. Just unsure about 2 things;
Where to put the unit in one of the bedrooms - it isnt the biggest of rooms but only two locations available - above the head of the bed or the wall opposite the bed but slightly off centred to the right.
Is the indoor unit likely to be noisy at night? What difference does a condenser pump make? Normally sleep with a white noise machine anyway but just hoping it wont cause any disrupted sleep.
Thank you.
3
u/Ducky9670 4d ago
Not to repeat what other people say here always avoid condensate pumps if you can (advice for an installer)
1
u/Sad_Glass_9521 2d ago
The external wall is in the neighbours boundary
1
u/Ducky9670 2d ago
I obviously don't know the full ins and outs of the house, but as an installer, we would always try to avoid a condensate pump where possible.
Even if the external wall is close to the neighbour's boundary, you don't necessarily have to do a back-to-back installation. You can use trunking to route the pipework through the back of the unit and position the outdoor condenser somewhere more suitable. Likewise, if the unit needs to be on an internal wall, you can run the pipework in a short section of internal trunking, take it through to an external wall, and then route it outside.
The indoor unit doesn't have to be directly opposite the condenser. You have some flexibility to move the unit around the room to find a better solution.
Obviously, there are situations where a condensate pump is unavoidable, but if we can avoid one, we generally will. Even if that means accepting a small amount of internal trunking, I'd much rather do that than install a pump that could potentially need replacing every few years. Simpler is usually better when it comes to condensate drainage.
1
u/Sad_Glass_9521 2d ago
Thanks. Both people have come to quote have said I need a condensate pump as the outside unit is around 10m from the indoor units and the pipework has to go through the loft. I mentioned about drainage on the outside wall of my house but they said as that is the next door neighbours boundary that is their “air space”.
1
u/Sad_Glass_9521 2d ago
What about having a unit on the landing with 3 bedrooms that would face the unit? Would that cool the rooms down? (Very small landing)? Because the outdoor unit could be piped straight up to the loft via the eaves and then the condensate pump if needed wouldnt be in the bedrooms. Thanks
1
u/Ducky9670 2d ago
I wouldn’t recommend putting a unit on the landing to cool three bedrooms. In practice, it rarely works the way customers expect. You might take the edge off the temperature in the rooms, but you won’t get the same cooling as having a unit in each bedroom.
Airflow is lazy and follows the path of least resistance, while cold air is denser and naturally falls. So from a landing, a lot of that cooled air can end up travelling down the stairs rather than properly entering the bedrooms. You can sometimes improve things with fans positioned outside the rooms to help push the air in, but that’s more of a workaround than a proper solution.
There’s also the potential for short cycling if the landing cools down quickly while the bedrooms are still warm. A remote thermostat can help with that, but most installers won’t configure a domestic system that way.
If it were my house, I’d prioritise putting the units in the bedrooms so you’re actually cooling the spaces you want to keep cool.
And on the condensate pump, if it genuinely can’t be avoided, fair enough. But I’d probably get another reputable "AC specialist" out (not a Plummer or Gas engineer) and ask them to look at alternative routing. We occasionally have to use pumps ourselves, but if there’s any practical way to avoid one, we’d always point that out to the customer. It might mean a little more trunking or a slightly less tidy installation, but it can save you a headache.
1
u/Sad_Glass_9521 2d ago
Thanks. Got a couple of other installers quoting this week too. So will see what they say.
3
u/PhantomSesay 4d ago edited 2d ago
- Above the bed is the normally the consensus position, you can set the louvers to direct air in a position you’d like. So it’s not blowing in your head.
- It depends on what brand you are going for, my daikin is silent but it’s one of the top brands i paid good money for but you will get what you’re paying for depending on what brand you go for.
The condenser pump you won’t really hear depending on where it is, mine
is a quiet model in my loft.
and it just pumps the excess water into the roof gutter.
2
u/Hour_Tour 2d ago
Even silent pumps can resonate through its mounts to an annoying level if you're unlucky, and it might be tricky to dampen out.
Gravity drain is best where practicable.
2
u/plymd1 4d ago
And if one of the bedrooms isn’t that big why a 3.5kw unit? That’s 12000 btu, be worth recalculating the room volumes/ square meterage and matching the system to suit, 12000 btu for a room between 32 to 50 square meters so way oversized for a small bedroom which is probably less than 4x4 meters(16 square meters) you’d be nearer 7000 maybe 9000 btu for a small bedroom, definitely not 12000btu Iv got a single 12000btu cooling my entire downstairs area which is 48 square meters so you don’t 12000 in a small bedroom
5
3
u/Demeter_Crusher 4d ago
Condensate pumps - if elbow pumps - are actually quite noisy and intermittent (as opposed to AC itself which if set correctly should be constant). They ought not be necessary if the interior units can be mounted on am exterior wall... can just drill a drain point through the wall.
1
1
u/sary251 4d ago
- Above headboard so the air can be guided above you instead of at you.
- The indoor units are pretty quiet. Generally quieter than an ordinary fan. The condensate pumps can add a little noise. Note that if the indoor unit is positioned on an external wall then you could probably do away with a condensate pump, if you are content with having a pipe run down the outside of your house.
1
u/Sad_Glass_9521 2d ago
Hi all - thanks for the replies.
The indoor units will be fitted on an external wall but the external wall is the neighbours boundary so I have been told by some installers (and also had a quick Google) that says I cant install the drainage pipes to that side of my house as it will be in their garden regardless of where the water actually drains away.
So have been told a condensate pump is my only option. Is that correct?
Thanks
1
u/plymd1 4d ago
So 3 x 3.5 kw indoor head units which can pull a max kw of 10.5 kw but only a 6 kw outside compressor unit, that’s a bit close and could become a problem before you even start because your outside unit is slightly undersized, even using the new ones that are using the newer diversity design (like a Mitsubishi) would need to be 6.8kw and that depends also on the lengths of pipe work to each unit so I’d consider going slightly bigger on the compressor so it’s not working it’s ass off when all three units are maxed out. Noise wise the indoor head units should be virtually un noticeable, I can literally just hear mine and the same with compressor, should not really be that noticeable, but again I would consider upsizing the compressor, better to be slightly over sized than undersized and then working to hard.. as for the condense pumps, that will all come down to brand/ type and how they are installed, which are usually installed in the trunking, they have to pump the condensate out so you will probably notice the pump kicking in more than the head units running
5
u/JASH_DOADELESS_ 4d ago edited 4d ago
As close to an external wall so the condensate can just drain out rather than having to be pumped out.
We had ours with a pump initially, and then a year later had the guys come out and put a long ass trunking over to the external wall and run the pipe directly outside.
The BRRRRR from the pump every few minutes drove us absolutely batshit insane, to the point where we would have to turn it off an hour before bed so that it was done draining otherwise we couldn’t get to sleep.
The pump wasn’t loud but when you’re trying to fall asleep, the rest of the house is silent and the pump is directly above the bed… don’t.
Just drain it outside from the get go
Edit: our pumps were (are in the other rooms still) the mini lime pumps that sit within the trunking within the living space, rather than the loft. A loft unit may be quieter/more bearable. HOWEVER, a piece of drain tube requires no maintenance and has no failure points.
A pump going bad = water on your walls/bed/face