Thread: Air conditioners

Originally Posted by dobbo

Can anyone tell me what is the maximum sized split system that can be used on 1 phase power without having problems?

go buy a fan

Most splits need 15 amps or beta a 3 hp shold run ok on a 15 amp outlet but u mite want to speak to a lecki to be sure

or u could jst go with my first response much cheaper or move closer to the coast no a/c needed here

cheers

chris

Originally Posted by dobbo

Can anyone tell me what is the maximum sized split system that can be used on 1 phase power without having problems?

It depends on if it's an inverter type split or a traditional type

Traditional about 36,000 btu/hr (or 3 tr) or (10.5 kw)

Inverter you may get up to 50,000 btu/hr (4.2 tr) or (14.6 kw)

and before you ask - you cannot measure cooling capacity in horse power

There are some 'chinese' inverters around which state that you can run 60,000 btu (5 tr) - but I wouldn't be game.

..........If you take the maximum size of the fuse/cable normally run in a house/appartment, which is 30 amps

30 amps x volts (220) = 6600 watts or 6.6 kw - so any unit that has an input power of less than 6 kw (10% margin)

IT will depend on a few things

1/ What size are your mains ? ( from the street to your house )

2/ You will need to do a maximum demand calculation on your house.

If all this is good then as long as its single phase your main manufacturers will go to 8kws cooling cycle heating is always slightly higher .

Mitsubishi heavy industries do go higher than 8kw but I am not sure how big they go.

Rule of thumb to figure out the size A/C you need

m2 x 150watts = kw

So measure your square meterage and multiply it by 150 that will give you your total watts required

eg: 6m x 6m = 36 x 150 = 5400w or 5.4kw

Hope this helps

Horse power is on older way of A/C sizing

8kw = 3.5hp

7.2 kw = 3hp

5.1kw = 2.5hp

These are only a rough estimate, but some older A/C installers still refer to HP for sizing.

Thanks for the info guys, now time do do some homework

From memory, most houses are supplied about 80A max. Could be 60. Check your main CB.

So, you can run anything up to 80A theoretically, but you'd probably want things like lights/refrigeration and power elsewhere etc etc... :-)

So, assume about 25A. That'll get you about a 7 or 8kw unit.

***NOTE***
Rated unit cooling/heating kW or hp does NOT translate directly to electrical kW/hp.

Gotta read the specs in the manual for peak current draw. Be careful of some of the cheap makes: they may not have 'soft-start' and peak current (at start up) will be significantly higher than rated current draw.

Dont most of those sytems need wiring in by an electrician etc anyway? Matt