Split system installation

Anyone installed one of these themselves? I saw a mistral split system at warehouse foor 500 and it looks good. Do they have all the gear to install?

Its worth paying someone else to install these things, mainly cause the risk of injury to someone without the skills and necesary equipment is very high.

If you value your back, you'll pay for someone else to do theirs :

If the system is to be hardwired into the power, which most are, you will need a qualified electrician to do this.

Also installing it yourself may void the warranty if its not installed properly. Sometimes these things are best left to the professionals.

Joe Blow said:

If the system is to be hardwired into the power, which most are, you will need a qualified electrician to do this.

Also installing it yourself may void the warranty if its not installed properly. Sometimes these things are best left to the professionals.

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Ok. I'm not worried about th electrical side of things, just the plumbing...

I think alot of systems need the compressor ? gassed after its installed as well.

numbercruncher said:

I think alot of systems need the compressor ? gassed after its installed as well.

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Ok thanks might just stick to a wall mounter job

Generally speaking, you'll need a refrigeration mechanic to sort out gassing the system and it wouldn't be worthwhile learning how to do it and buying the necessary equipment unless you're going to be insalling a lot more than just one system.

As for the power, if it draws 10 amp or less then you could plug it in to a power point. Anything over 10 amp and you'll need an electrician to either hard wire it or install a larger power point. Hard wired is the way to go if you don't want cables visible.

Even if you can plug it in, you should be aware that your house probably has only two power circuits each rated at 16 amp total. If you're going to plug in a single appliance that runs for long periods drawing 10 amp or thereabouts then odds are you'll end up blowing fuses / tripping circuit breakers quite regularly.

In a few locations you can get discounted electricity if it's hard wired. This applies to all of Tas (except King and Flinders Islands) where you would connect it to the HydroHeat rate (Tariff 42) via a separate meter. At least one supplier in Victoria has a similar offer.

Unless you live in an area that needs no heating, I'd certainly get a reverse cycle system rather than cooling only. The cost of heat (and greenhouse gas emissions) from such units is roughly one third that from an ordinary electric heater and is competitive with natural gas. Far cheaper than heating oil or LPG too.

I heat most of the house (lounge, kitchen, dining, hall and one bedroom door always open) with a 4kW split system and it only costs about $360 a year running 24/7 at 21 degrees (the house is fairly well insulated). It would cost $1080 to do the same with a non-A/C hard wired electric heater, $850 with natural gas (not that I have that option anyway), $2500 with LPG or $2100 with oil.

Those rates will vary between states. The figures are based on 9c / KWh for electricity, 5.6 c / KWh (1.56c / MJ) for natural gas, $1.33 per litre for oil and $104 per 45Kg LPG cylinder. Efficiency taken as 300% for the air-conditioner, 80% for gas and 70% for oil. Your power / gas bills should show what rate you are paying if you want to compare.

I wouldn't advise relying on an air-conditioner for heating if it goes much below zero degrees however as icing on the outside coils will be a problem. It will work but the heat output will fall when you need it most. Either have something else as back-up for when it's really cold to get some extra heat or get a wood / gas / big electric space heater instead. Sydney / Melbourne / Brisbane / Adelaide / Perth / Hobart are all warm enough for it to work fine. Launceston there will be a few issues on the coldest nights but nothing a plug-in fan heater won't fix. Canberra, mountains etc there will be problems with most sytems in mid-winter however and I'd suggest you don't rely on A/C for heating there without a back-up of some sort. Some systems will cope but I wouldn't count on it.

One thing to be aware of is that there are plenty of cheap and nasty systems out there that don't perform as claimed. Personally I'd stick to the well known Japanese brands if you want to be sure it will work rather than just burning up power. If it's for heavy use or in a cold climate for heating then I'd go for Daikin, Panasonic etc. If you're in Sydney etc and don't plan on heavy use then the cheapies will probably be OK but I don't trust their efficiency claims.

Ok thanks smurf. My friend lives in tropics so wont be using it for heating, just the airconditioning, so might just try a cheapy and see what happens.

Smurf1976 said:

One thing to be aware of is that there are plenty of cheap and nasty systems out there that don't perform as claimed. Personally I'd stick to the well known Japanese brands if you want to be sure it will work rather than just burning up power. If it's for heavy use or in a cold climate for heating then I'd go for Daikin, Panasonic etc. If you're in Sydney etc and don't plan on heavy use then the cheapies will probably be OK but I don't trust their efficiency claims.

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Daikin is claimed to be the best, but is priced accordingly.

I heard that Mitsubishi Heavy Industries models are well priced to what they actually do and are reliable, which is probably important too.
(Mitsubishi models are not as praised as Mitsubishi Heavy Industries ones)

As to installation, you can install bracket on the wall for internal unit, punch hole through the wall, install stand for external unit, pull gas tubing and cover it with insulation, condensation pipe and cables, then get Electrician licensed for AC and get him / her to hook it up.

65 to 80 mm round hole in the wall should be enough to accommodate cables, insulated copper tube and condensation tube.

But as mentioned before, professionals will take couple of hours to do the lot, compared to maybe couple of days.

Happy said:

Daikin is claimed to be the best, but is priced accordingly.

I heard that Mitsubishi Heavy Industries models are well priced to what they actually do and are reliable, which is probably important too.
(Mitsubishi models are not as praised as Mitsubishi Heavy Industries ones)

As to installation, you can install bracket on the wall for internal unit, punch hole through the wall, install stand for external unit, pull gas tubing and cover it with insulation, condensation pipe and cables, then get Electrician licensed for AC and get him / her to hook it up.

65 to 80 mm round hole in the wall should be enough to accommodate cables, insulated copper tube and condensation tube.

But as mentioned before, professionals will take couple of hours to do the lot, compared to maybe couple of days.

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Agreed there. You could do much of the installation yourself and leave the gassing and electrical to a professional.

One thing you don't want a professional doing is installing a power point next to the A/C unit and plugging it in with cables visible. There's no reason (in 99.99% of cases at least) to not run the wiring directly into the unit with nothing visible inside. In Tas you can't get the cheaper power if it's plugged in so nobody does it here but I've seen it done that way elsewhere. Looks ugly.

As for brands, Mitsubishi Heavy Industries is generally seen as superior to Mitsubishi Electric even though both are part of the same (much larger than most realise by the way) company. Both are quite good however.

Daikin are commonly viewed as being top of the range especially for heating (some models incorporate a booster element for cold climates). Panasonic are also very good in my experience.

I've fixed a disproportionate number of problems with Fujitsu A/C. The electronics were the problem. That might be fixed in the newer models though (these were late 1990's and failed after about 5 years).

Whatever you do, one thing to remember. Not cleaning the filters eventually kills A/C units (especially in machines used solely for heating though dirty filters are never good even with 100% cooling use). Clean them every 2 weeks if in use 24/7 unless it's a very clean environment. Less often if it's not running all the time.

Beware of dirt accumulating in the outside unit too if it's a reverse cycle model. Condensation from the heat exchanger in heating mode won't be able to drain away if the drain holes (which tend to be tiny) are blocked and this will lead to rust.

A word about fan speeds. In cooling mode, lower fan speed will remove more moisture (useful in humid areas) at the expense of higher power bills. You're better off with the fan on high or auto in a dry climate. In heating mode, lower fan speeds will use more power to maintain the same temperature and there is no issue with humidity control (since the water being extracted will be from the outside, not inside, air).

This doesn't apply to modern inverter units however - they maintain efficiency regardless of fan speed. They would certainly be a better option if you want low noise levels without losing efficiency. You'll know if it's an inverter because the manufacturer will generally make a point of it as a feature.

Ok before I go and buy this thing, I am assuming it has to be recycling the air already in the room... How do I ventilate, and is that necessary to optimum performance?

Under normal circumstances you wouldn't want any more than the minimum ventilation required to keep the air in the room fresh if there was no A/C. Same as you would do if you had a heater running in a cool climate - windows shut if the room has a ventilator, maybe open slightly if not.

Whilst the A/C will remove moisture from the air, this isn't generally a problem unless you're in a dry climate (eg Adelaide) to start with. Even there, the reality that cool air is able to hold less moisture than warm air anyway means it normally won't be a serious problem. Lower fan speed will remove more moisture (and use more power with non-inverter units) at any given room temperature and vice versa.

One thing you should not do is direct the cold air stream from any A/C directly onto people. At best you'll feel very uncomfortable. Some people will actually feel quite ill after getting a lung full of cold air blown stright in their nose / mouth. Aim the vent as high as possible toward the ceiling if you want it to cool the room properly. In the same way aim the vent of any heating device as low as possible towards the floor if you want to heat the whole room properly.

Smurf1976 said:

One thing you should not do is direct the cold air stream from any A/C directly onto people.

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Just to add, do not direct warm/hot air onto a 1lt bottle of olive oil filled to the brim by one's teenage son, ie decanted from a 4lt container to a 1lt bottle with absolutely no air gap.

After an hour or so that 'tink' sound of the bottle breaking leads to a lot, and I mean a lot, of cleaning up of olive oil.

Flying Fish said:

Ok. I'm not worried about th electrical side of things, just the plumbing...

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Are you sure it's not three phase? These aren't 'plug and play' units!!

It will also need to be switched to it's own circuit breaker..

Make sure you actually have enough supply to run the thing.. !


Ventilation is not an issue, refrig systems have their own 'return air'

1234 said:

Are you sure it's not three phase? These aren't 'plug and play' units!!

It will also need to be switched to it's own circuit breaker..

Make sure you actually have enough supply to run the thing.. !


Ventilation is not an issue, refrig systems have their own 'return air'

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Not many houshold ac are three phase. Three phase is only really for industrial stuff and very few houses have it or require. The smaller units could at a pinch be plugged into a gpo, but I wouldn't personally do it. IT might not necassaily require its own breaker since its only a small unit about 2HP. Anyway, a mate is a sparky so I'll let him take care of that side of things