Air conditioning thread

The temperature in the SE is expected to reach 32 by Wednesday of this coming week. This space is therefore reserved for the air conditioning thread.

Reply to
Simon Gardner
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Good plan. I'll kick off.

I want to install aircon in the office - which is south facing, with a big window, and about 3.5x4.5m. With blinds, I reckon I need about 2-3kW of cooling.

I want a split unit, and I intend to put a hole in the (external) wall, and put the pipes/cables through it.

I would like a recommendation of a make/model and supplier please.

I've googled this one to death, and phoned several suppliers, who were quite frankly morons. I know there must be good ones out there, but they clearly don't have well promoted websites.

It's important that the heat exchanger can be permanently mounted on the outside of the house. This really seems to throw the suppliers, and they come up with lines like "well, it's not meant for outside installation, but it'll probably be ok".

Reply to
Grunff

Lets hope if it gets going we don't end up with yet another multi kb thread of Andy trying to educate International Mouth of Dysentry over basic physics in THIS universe!

I notice that heat pumps are being discussed in this summers trade mags:-)

Reply to
John

That's how its done. Mine is humming softly as I write.

I'm not at all surprised about the websites. These are *small* firms in general. It's generally not considered a DIY job either (except for window rattlers). However, Yellow pages should find you a dozen local firms. I had no trouble getting three quotes when I installed mine. You might try eyp.co.uk and search a reasonable area since these firms supply some distance.

Fujitsu air con is on 020 8421 7000. Mitsubishi Electric air con on 01707

282880.
Reply to
Simon Gardner

Shows where the profit is then. Play them at their own game, get a quote off them and see what gear they suggest.

Reply to
James Hart

Right!, I think that may be the problem. Its not something I'd like to install or work on myself as specialist equipment is required. I believe that they still are a bit fussy re the gasses involved, but really for what you can get a system installed for its quite good value...

Reply to
tony sayer

Your application seems to occupy that no-mans land between domestic single-pak units and the big commercial splits. I'd be tempted to go for one of the pre-gassed splits which are intended for non-a/c trades to install. (This electrician and fridge-mender has installed four). Suggest the ones from Addvent (part of City Electrical Factors) which I'd reckon are OK for a competent, well tooled, DIYer to install.

Reply to
impvan

installation ,however - unlike some of the other suppliers.

They also have a paragraph on their web site saying that it isn't worth considering fitting yourself because the prices to install are so low.

The other supplier mentioned that it takes about two hours to fit a split system yourself. That's probably optimistic and does not include running the power to the appropriate place(s), so realistically half a day.

That being the case, professional installation, assuming it's done properly, isn't going to be that cheap and I think I prefer to make the judgment call on whether it's worth installing myself or not.

The other supplier has self -install packages, but only for up to a certain power level and length of refrigerant lines - not a bad idea it seems.

I wonder if any of the suppliers will do just a commissioning service, where they supply equipment and instructions to fit, and then offer a commissioning service to check and charge the system.

.andy

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Reply to
Andy Hall

They were one of the people I called, and were frankly quite unhelpful. Maybe I got the wrong guy and the rest of the staff are great, maybe they're all like that. I'll never find out.

Reply to
Grunff

It took the insatllers of my system (two 3.5KW units inside and a common condenser outside) most of a day to fit it. I'd have thought two hours exceedingly optimistic for DIY.

Reply to
Simon Gardner

How many rooms does that cover and how large, Simon? What make did you buy?

.andy

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Reply to
Andy Hall

It now looks like UK maximums of

33C Monday 33C Tuesday 34C Wednesday
Reply to
Simon Gardner

It basically covers the two rooms. I'll measure them sometime (or dig out the quotes) but they aren't huge. OTOH there is an unusually large amount of electronics in them and they both get morning and afternoon sun.

They are Mitsubishi units.

Some of the quotes I got were (I felt) underspecified (hadn't taken the electronics enough into account) and as it turns out I certainly wouldn't have wanted any less than the 7kW total for the two rooms that we ended up getting. I prefer an ambient 20 or at most 21 if working. The system copes with external temperatures peaking at 32 for days on end but certainly wouldn't if it had been smaller.

Reply to
Simon Gardner

Thanks.

Presumably the cooling capacity/power is determined by the outside unit?

Do the suppliers specify a temperature drop that will be achieved for a given power level or something similar? i.e. like central heating but the other way round?

.andy

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Reply to
Andy Hall

It's determined by both. But the spec of the outside unit must be sufficient to drive the inside one(s).

I specified a temperature drop. They quoted to meet that. But the actual specs of the units are power (ie kW).

Reply to
Simon Gardner

Having just been saunad in my loft I am considering lo-tech solutions.

Heat is via roof. Roof is tile. Old way of cooling water is to put in porous pot and allow evapouration to keep water cool. Hmm.....

If I was to run one of those automatic watering hose pipes (the ones with loads of small holes all the way along) along the ridge of the roof, then allow a small flow of water down the roof over the tiles, wouldn't that keep the roof void cool and reduce the heating effect for the rest of the house? [Granted that loft insulation should be keeping the heat from coming down in the summer as well as going up in the winter] The South facing roof slope also drains into a water butt so any run off would not be wasted.

Test spray with a hose pipe may be in order :-)

As I am not on a water meter so far this would also be an economical solution. Water valve in loft controlled by thermostat?

Cheeers Dave R

Reply to
David W.E. Roberts

Be interested to know the cost, if you can remember.

Reply to
parish

No. The units and all the pipework is already filled with gas under a positive pressure. The pipes connect with fittings similar to the hydraulic fittings you get on tractors/plant (only smaller), so no brazing/nitrogen flushing/vacuum required.

Reply to
impvan

Wouldn't it make the 'internal' heat exchanger rather large?

Reply to
Dave Plowman

I can't think why it would be any different -- indeed they look exactly the same as the refrigerent filled evaporators to me. The ends of the heat exchanger are different -- standard plumbing, gate valves, etc. which is why it struck me as much more DIYable.

Reply to
Andrew Gabriel

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