DIY split air conditioner installation - what are the pitfalls?

I've just had a loft conversion done (not DIY I should add), and I'm looking to install an air conditioner.
I'm looking at a split unit because they are so much better than the portable ones that I've tried before. At the moment I've got my eye on the LG S12 AW, which does both cooling and heating.
Does anyone have any pointers as to what to look out for, and whether this is a reasonable DIY project?
As far as I can see, the key things to do are:
1. Get electrical connection for the unit (I'm getting an electrician to do this). 2. Mount the internal unit 3. Drill hole through wall for the pipe 4. Route pipe through the hole and down the outside wall 5. Mount external unit on outside wall 6. Connect pipe, electricity Etc.
Is that about it? Are there any special tools required for connecting the pipes, and do they need to be purged of air with special equipment? I've been looking on the net for installation guides, but can't find any.
Is the siting of the external unit something that needs permission from the council (Medway if it makes any difference)? I'm planning to put it on the side of the house near the back so it won't be obviously visible from the road.
Any hints from people who've done this before? Any links to installation guides would be most welcome.
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A 'standard' split install needs some specialist tools - a vacuum pump, pipe flaring tool, a manifold gauge, MAPP gas or oxyacetylene blowtorch ( might just get away with a really powerful propane/butane one) , and ideally a cylinder of something (co2, argon, n2) to do a leaktest under pressure. Plus the consumables - piping and insulation, copper brazing rod, maybe a condensate pump if there isn't a gravity runoff route available. They come pre-charged so no need for refrigerant unless pipe run is really long.
This is all perfectly DIY-able in principle, and you can probably just about break even on the tools by 'hiring' off ebay, or buying new and selling on same afterwards. - www.srw.co.uk or http://www.hrponline.co.uk/ do everything you need. The latter have a number of walk-in counters around the country. (I've seen things like manifold gauges sell on ebay for twice what srw sell them for)
However if you're talking about getting an electrician in just to wire it up, the rest may also be a little ambitious...
However there are 'diy install' models around that can be done rather easier - I don't know how they handle the vacuuming/sealing side of things, or how flexible they are regarding pipework lengths etc.
Info is rather hard to come by as the industry is rather self-protective and doesn't seem to take kindly to mere mortals encroaching on their territory...... However it's actually only marginally more involved than plumbing.
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wrote:

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If they come pre-charged, what happens to the air in the pipes connecting the heat pump unit to the radiator / fan unit ? I assumed (always dangerous!) that they would come devoid of refrigerant, and were connected, tested for leaks, then evacuated and a weighed quantity of refrigerant allowed to be sucked in by the vacuum. But then I've never done it, only used completed chiller units industrially.
AWEM
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Both the inside and outside parts come pre-pressurised. They use a connector which remains sealed until the two parts are coupled together. I installed two of them last year, and they're still working fine.

There's been a big mark-up in this country, although that's changing. It might be that they want to protect that, but I suspect it's more a case of it being quite new in the UK domestic market and it's only just started moving from a luxury to a commodity, and that will bring prices nearer to those in other parts of EU. Units can be picked up more cheaply in the hotter parts of Europe, and much more cheaply from the US (a colleague bought one back from the US a few years ago, where it was a tiny fraction of the price they were here at the time).
I got mine from B&Q when they were 100 off. Most specialist suppliers will supply at 5% VAT (applicable to heat pump heating systems for home use only); B&Q wouldn't but were cheaper with the 100 off. If they don't have a deal, you might want to check other suppliers such as Global Cooling (not used them myself, but I've heard good reports).
--
Andrew Gabriel
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On 05 Aug 2007 19:06:00 GMT, snipped-for-privacy@cucumber.demon.co.uk (Andrew Gabriel) wrote:

Does that mean they come with a fixed length of (flexible?) pipe?
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Yes. Some of the B&Q ones had pre-pressurised extension pipe available too, but you were only allowed to fit one extension piece. That might have been because the electrical part of the interconnection was the right length for one extension piece, and no extension was available for that.
--
Andrew Gabriel
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wrote:

Gas welding is beyond what I'm comfortable with, and as I don't have the equipment it's probably prohibitively expensive for a one-off job anyway.
I assume that the welding and pressure-testing is for terminating the pipes that connect the inside unit to the outside one. I've seen some pre-made pipes for sale, but I guess these are for the DIY versions.

I'm getting the electrician to wire up the whole converted loft, so I'm going to get the A/C connection done at the same time. However, it's still a valid point.

That's what I've found. It's simple enough to buy the units, but there are no pre-sales installation details available. I'm loathed to buy one in case I find that it's too complex for me to fit, and A/C companies don't want to touch it because they make most of their money on the mark-up of the unit.
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Have a look at http://www.global-cooling.co.uk/ I bought one of their units 2 years sgo, installed it myself and it's been fine. They have a facility to hire a vacuum pump for purging. There is install instructions on their website somewhere too.
Alan.
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Not welding really - just like soldering but a higher temperature (cherry red). Not at all hard - if you can use end-feed fittings it's no problem - with the right rods you don't even need to worry about fluxing.
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Why can't you just solder?
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I don't know, but there must be a good reason as refrigeration and A/C pipes are always brazed, not soldered. Maybe brittleness at lower temperatures, or flux contamination.
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On Sun, 05 Aug 2007 18:32:18 GMT, Mike Harrison

Depends what you mean by "standard". For the ones sold onto the DIY market you don't need any of those unless you are altering the supplied pipe length.

Supplied.
You can use a vacuum pump or simply follow the instructions and use the refrigerant to purge the air in the pipes.
--
Peter Parry.
http://www.wpp.ltd.uk/
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Ours certainly attracted the attention of the neighbours, and then the "landlord" - developer, stepped in. Fortunately B&Q (the stockist of mine) just started advertising a 2m extension kit that allowed me to drop it to the floor. 10 weeks of hell trying to get that delivered from B&Q (never, ever again) and all was sorted.
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wrote:

I'm planning to site the external unit near to ground level as well. This will make it less obtrusive, and should also make it easier to service when needed. The connecting pipe will need to be longer as it will run down the outside wall, but it's well within the spec of the unit I'm looking at.
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