PDA

View Full Version : Is a 3 phase aircon better to single phase


oadis
Jul 22, 2010, 10:40 PM
I am wanting to take my evaporative out and get a ducted system to my house which is only a single storey home. There is going to be 9 outlets with 5 zones. I have a choice of getting a single phase 14.5KW LG or I can 3phase 14KW Fujitsu with the same outlets and zones. The Fujitsu is a little more but I believe the 3 phase is better in the long run as it's more economical. Is this true?

Thank you

KISS
Jul 22, 2010, 10:45 PM
Homes don't normally have 3 phase power e.g. 208 (3 phase)/120. There are few exceptions. Most homes has 240/120 single phase power.

oadis
Jul 22, 2010, 10:56 PM
I don't understand e.g. 208(3 phase)/120 240/120 single

wmproop
Jul 22, 2010, 10:59 PM
I`ve never known a house to have 3 phase power,
But I guess anything is possible
If you have 3 phase or can get it,yes it would be cheaper to operate heating and cooling system

wmproop
Jul 22, 2010, 11:03 PM
I don't understand eg 208(3 phase)/120 240/120 single

if you have 3 phase =you would have 208/120 volts

if you have 1 phase= 240/120 volts

KISS
Jul 22, 2010, 11:06 PM
Most homes (probably 98%) are supplied with single phase power in the US.

240 Volts is used by water heaters, ranges and air conditioners.
120 Volts is used by the smaller appliances

Businesses can be supplied with 3 phase power. This is desirable for motor loads. 208 V usually means there is 3 phase in the building somewhere.

Some breakers will have three breakers tied together.

I doubt you have 3 phase power in residential.

oadis
Jul 22, 2010, 11:12 PM
We only have 240volts here and yes you can get 3 phase power for homes

wmproop
Jul 23, 2010, 12:12 AM
? Can you have 208V-3 phase
And 240V single phase
Both in the same house?
I`m not to old learn

Would you have to have 2 different power/breaker boxes?
1 for 1 phase,, 1 for 3 phase?

KISS
Jul 23, 2010, 03:40 AM
wmproop:

If you want to get confused, take a look at this: 120/240 Volt 3-Phase Delta High Leg - Electrician Talk - Professional Electrical Contractors Forum (http://www.electriciantalk.com/f9/120-240-volt-3-phase-delta-high-leg-5166/)

And

http://www.cleco.com/uploads/ThreePhaseResidentialService.pdf

KISS
Jul 23, 2010, 04:04 AM
Providing you know what kind of 3 phase power you have: 208 Y and 240 high leg delta and the system is compatible with that power source, your OK.

3 phase motors are more reliable and are generally more efficient than their single phase counterparts. Many heating systems use an ECM motor which is essentially 3 phase that's operated off a controller running on single phase. The wire size is typically smaller as well.

There may or may not be a benefit for you. You also may have to qualify for 3 phase power.