Air conditioning

[Huge]

My 20 y/o Haier monobloc ("portable"!!!) air conditioner has gone bang (well, it went "beep, beep, beep, beep, etc. in the night, I unplugged it to shut it up and this morning it is dead. It wasn't running.) I've done all the usual checks (mains, fuses, etc.), and looked inside and there's nothing obviously wrong, so it looks like it's going in the (metaphorical) skip (*), since the chances of getting it repaired are very small. Haier's website even denies it exists.

So ... looks like a good opportunity to install a proper split unit! Any recommendations? I'll have another read of the excellent Wiki article recently posted. It's for a 20ft x 20ft North-east facing bedroom that gets lots of sun in the mornings. A split unit would be better anyway, since we could run it all night - the Haier used to fill its condensate tank and give up about 2AM.

(* At the nearest refrigerator recycling place, since it's presumably full of ozone-eaters.)

[Nightjar]

Make sure you buy one intended for use in the UK. Not all are and units intended for hotter climates can't always cope with our winters.

[Huge]

I won't be running it in the winter. Our bedroom is too hot.

[Andrew Gabriel]

I had a dehumidifier that died. It was the microcontroller board that had died. It now has a Raspberry Pi replacing that, which means I can control it via the web/phone, see what the humidity is, etc.

The Pi drives two outputs to switch the compressor and the fan, reads the room temperature and humidity, the evaporator temperature (to protect against freezing up, which never worked with the original microcontroller althouth it tried) and the tank full microswitch.

The Pi also keeps track of the running costs (knowing the power consumption and the operating duration), and reports the temperature and humidity which the original microcontroller never did.

[Huge]

Unfortunately, this requires skills I do not have.

[Bob Minchin]

Very pleased with our Mitsubishi Electric** split aircon. I know you don't want heating but as it is reversible it qualifies for environmentally efficient system and hence 5% VAT. The difference meant that I did not DIY it which would have involved hiring a vacuum pump and paying 20% vat on the lot and limited warranty

** There are two parts of Mitsubishi group that do aircon units and they are not the same. Dealers and fitters tend to do one brand or the other. Caused me a lot of confusion when searching for specs, dimensions etc.

HTH Bob

[Huge]

[17 lines snipped]

How much did it cost you? My wife has suggested we pay someone to install it, but I'm not keen since it doesn't look beyond my abilities.

[Bob Minchin]

It was about £1750. inc vat. I felt similarly. Yes I could have done it a bit cheaper DIY but would have had to hire the vac pump and flaring tools and provide the pipework, insulation, drain etc and would have had minimal warranty. I did prepare all the electrics to their spec. Switched power goes to the outside unit only and a control and power cable follows the pipework route from outside to inside unit. The fitter had brazing gear to do the pipe joints and all the neat ducting fittings and anti vibration mounts for a tidy job. I did specify a larger outdoor unit so the system could be extended to more rooms at a later stage so you might be able to save a bit on that. Bob

[Huge]

eek.

The kit I'm proposing to install is specifically designed for DIY. See;

So I don't need any of that.

That is a concern.

[Bob Minchin]

I feel it would be unwise not to pump down the pipework which removes virtually all the air and moisture from the indoor unit and pipework whilst coincidentally checking for leaks before releasing the gas. My outdoor unit was also precharged with gas in the same way as the DIY systems are.

[Bob Minchin]

Having read through the (excellent) write up, I wonder if the indoor unit is not precharged with air as Richard writes but instead has a little refrigerant gas included which would be better for the whole system rather than air and water vapour. I presume there can be no warranty for problems arising from the installation.

[Andrew]

But you could approach the problem from another angle; why is the room getting so hot, and are there any passive heat reduction measures that could be used ?.