Why are there system 4 or System 5 aircon but yet you can’t turn on all 4 aircon at the same time?

[MeOw33MeOw]

It’s the power supply for your house.

For those staying in private estate if they want to on more air con they also need to change the cable to allow bigger power supply

 

[randyap]

I just dont understand
if a compressor
cannot allow all 4 aircon to
turn on at same time
why are there system 4 or 5?

you can, just that the cooling is slower. Majority of households will never on 4 or 5 units a the same time. If you will never on all units at the same time, why bother to overkill and make it more expensive. For households who really need to on all at the same time, just get 2 compressors.

 

[thretiredDad]

All along it's this kind of setup as the compressor will never be able to fully meet the requirement for all blowers unless you install 2 compressor but that'll increase the cost a lot. It's also a way to keep the cost down too and you seldom need to operate all blowers unless you're having guest in living and rooms are occupied as well.

True
not all the time all 4 aircon will be on
unless I have guests coming at night

most of the time
day time - 2 bedroom + 1 living room
night time - 3 bedrooms

 

[thretiredDad]

I am not an ac guy la. Unless you host parties often and assuming all bed rooms have occupants, I would rather have my 3 bedrooms using 24k btu . Sleep with ac more important to me .

Bedroom using 24 btu?
I thought 9k for bedroom is enough

 

[menthol28]

40-60amp?
Take note - The power socket has a limit…

Changing HDB kitchen 13A socket to 15A​

https://forums.hardwarezone.com.sg/threads/changing-hdb-kitchen-13a-socket-to-15a.5678357/

If u dunno Mai Kay kiang, HDB flats aft 1990s all come with incoming 40amp DB. You are talking about power socket, I'm stating the main DB. Go check HDB website. Really jump the pig. When the AC ppl install AC they will change to 15amp power socket.

 

[menthol28]

True
not all the time all 4 aircon will be on
unless I have guests coming at night

most of the time
day time - 2 bedroom + 1 living room
night time - 3 bedrooms

Then just get the sys 4/5. If you dun on all AC all the time and 24 hours non stop, it won't be a problem. I think the AC tech or sales staff u spoke to is inexperienced

 

[Tschuus]

Bedroom using 24 btu?
I thought 9k for bedroom is enough

dont you have 3 rooms sharing the 24btu ? Or you will be only using one at a time ?

 

[MoeLanYong]

You can turn on all. Just not cold.

Because the contractors usually calculate the BTU needed per room. Then assume you won't be in all 4 rooms. So they recommend you a system 4. Which really is insufficient for all 4 rooms.

I by-pass this by buying 2 system 4. I have 2 condensers at the back.

For one room, I even have 2 fan coils.

So all my rooms are 24/7 switched on. Cold.

 

[Wu-Han Clan]

install 2 compressor lah...

 

[SpeedingBullet]

do some basic math. why ppl dont bother to even research a little before buying?

 

[tank_t]

optimally 2?
if I turn on all 4 aircon at same time?
only 2 rooms will be cold?
the other 2 room no cold air
even if I turn full fan + 16 deg?

okay i try to explain.

The compressor has a limited capacity to take the heat from the coolant. If u on too many unit together, the coolant will get warmer faster and the compressor will chill the coolant fast enough. So its the coolant temp that goes up and become inefficient in cooling.

the compressor is limited cos of the physical design.

if u want to on all units together many need to manage the expected tempreture. Maybe set at 25.

 

[amekago]

I was looking at this
living room -24k
3 bedroom - 12k
but the aircon sales
told me yes it is possible
but only 1 room at a time
if all 4 units aircon are on the same time
will not be strong enough to support

so total is 60,000 BTU

go Google 60,000 BTU aircon compressor, u will see it's like 2 compressors stack onto each other into 1 single unit, many manufacturers make these, but their intended end users is more heavy duty like cassette aircons for commercial and industrial

but how many HDB / condo will need this? doesn't make sense for retailers to stock 2 SKU....so the simplest way is to ask u to install 2 X compressor, case closed


Read HWZ Forum Rules!

 

[jumpthepig]

If u dunno Mai Kay kiang, HDB flats aft 1990s all come with incoming 40amp DB. You are talking about power socket, I'm stating the main DB. Go check HDB website. Really jump the pig. When the AC ppl install AC they will change to 15amp power socket.

So those power socket limit is false information?…….Inform power socket limit = Kay kiang?

• The running current of air-conditioner should be restricted by a 20 amps double pole (DP) isolator or 15 amps power point
• A maximum of 2 split-type air-conditioner condensing units can be installed

https://www.hdb.gov.sg/residential/.../guidelines/airconditioner-installation-works

8.5a Current Limit For Old Resale Flats​

https://www.renotalk.com/forum/topic/8196-85a-current-limit-for-old-resale-flats/


Who said that your 40amp DB information is incorrect?

 

[swordspirit]

I am looking at this
12k for my 3 bedroom
24k for my living room

To on all 4, u need ard 60kbtu. Your compressor only 33kbtu. Max 3 bedrooms at the same time or living room + 1.bedroom.

 

[Tschuus]

do some basic math. why ppl dont bother to even research a little before buying?

Bec they like to be confused by all the BS on edmw?

 

[Zze121]

1 compressor pump gas to 2 to 3 blowers @ the same time, gas in 1 pump shared by 2 to 3 blowers, nearest cool faster
if logic works well, more cool gas regulate to the furthest blowers

 

[eeLoyH]

Is for all air con
including starmex or daikin
i just find it stupid
have to buy 2 compressors
3+1
rather than 1 system 4 compressor

It’s rather simple to understand.
1 motor 4 outlets; all on at same time the capacity is reduced to 1/4
vs
1 motor 2 outlets; on at same time it’s 1/2 strength

so I’m sure you can cheapo and save on system 4,5,6,7 but don’t expect the same strength coming out and complain on heat

 

[yoongf]

38k btu compressor will require 32A isolator.
48k btu is already at 80kg, the maximum limit for HDB aircon ledge, assuming the window is big enough to squeeze compressor.

60k btu single unit compressor in HDB will really need a alibaba contractor to arrange.

 

[Alphidius]

Just calculate the BTU needed and buy the right capacity...

https://www.luceaircon.sg/blog-arti...-to-use-it-to-choose-the-right-aircon-for-you

 

[Thoma5]

Room need so big btu meh? Thought 9k…
I 3 rm flat… 1 compressor nia… total 31k… on 3 will cold but take longer time to cool down…
Those old flat how to put 2 compressor ah?