Residential Central AC Systems

[airuma]

airuma, this is the ole talk section, but we have lots of people here with industry experience in many different fields. AC systems is one of them. Can you tell us where you can get a "36,000 btu that operates on single phase" and is that for the AHU and the chiller sections?

As with all trades, some craftsmen have different experiences and preferences. I would assume that alex jj meant that one unit could be put out of commission and leave the other working while the compressor is running rather than letting one just run properly while the other one makes ice and sweating water.

Actually I don't know much about central AC units. I was just assuming that since some of the 36,000 btu mini split condensers look exactly like some of the 36,000 btu central condensers that it would be possible to use a single phase condensing unit with a central system. I think we did actually have one in existence before we changed to a 5 ton 3 phase but that was about 8 years ago.

On the other hand, my point is we cannot assume that we are installing this unit in another country, we must take culture into consideration. We trinis generally don't practice preventive maintenance and sleeping anywhere other than your bedroom is never as comfortable. Apart from that, at least two times I had my bedroom unit serviced and it started to leak after the service (Innovair Vexus 18,000 btu)

I just don't like when people "bad talk" something when they really don't have any empirical information to back it up, I think we get enough of that from the politicians and we should bring about the change because they won't.

Why didn't anyone suggest central for the common areas of the house and mini splits for the bedrooms?

[ronsin1]

Sorry to hijack ur ched Rainy...
But as all the AC experts here, have any of you locally connected a Nest Thermostat to a split AC unit?

I was only looking at this yesterday I might be experimenting soon

[ronsin1]

Not really economical to install a central AC system in a residential house
It best to use individual split unless you have an open floor plan in which you need a 5 ton or bigger

Please enlighten us with your economic analysis. As with most things, there is no best here. It depends on your needs and budget. As someone said before, large open floor plan, mini split just would not cut it. If you are going mini split, placement of the evaporator would be important and in many cases the placement of the condenser and length of copper determines the placement of the evaporator. With mini split, think about it, all of the cold air comes from one point and the rest is up to natural convection. To get efficient cooling you will need to introduce forced convection which will send up your cost and electricity usage.
IMHO, the 3 phase limitation is about the biggest single factor to consider but you should be able to get at least a 36,000 btu that operates on single phase.

did you read my post properly I never said to condition a space with mini splits I said it is not economical unless you have an open floor plan in which you need a 5 ton or bigger


Also I agree with your point that each unit has its advantages and disadvantages

will you installation one central unit in your house which supplies air to different rooms example living room and bed room

you will be wasting energy but then again a lot of people thing that because Trinidad energy cost low they can waste it instead of reducing the carbon foot print


you need to consider the cost per ton to install a ducted split which is give or take $8,000.00 per ton including electrical supply

also consider the operating cost

let say you have a 5 ton unit which is supplied by a 40 amp 230 V 60 hz 1ph supply the RLA is about 30 amps and the electricity rate is approx $0.26 per KWh factor in the unit will be running approx 12 hours for an average of 30 days per month

40 amps X 230 Volts= 6,900 Watts or 6.9 KW

6.9 KW X 12 hr= 82.8 KWh

82.8 KWh X 30 days =2484 KWh

2484 KWh X $0.26= $645.84 per month

please check the other AC thread for a 12,000 BTU operating cost calculation

Mexican You can however get a 18,000 BTU ducted split however most suppliers in Trinidad are unwilling to bring this in as sales for this is not as good as a 18,000 BTU mini split

you can also get a top discharged unit if you want and not side discharge it is a bit more expensive

the install cost based on averages the ducted split will cost you between $10,000 and $12,000 for installation while a mini split will cost you about $4,000 installed


oh 250 ft is real madness

[wheelbarrow]

Sorry to hijack ur ched Rainy...
But as all the AC experts here, have any of you locally connected a Nest Thermostat to a split AC unit?

I was only looking at this yesterday I might be experimenting soon

Nice.
I saw one connected locally on a central AC and I like the features.
I'm reading online that it's possible with some know-how of the split AC circuit board.
I'm guessing that you have to get that control circuit board to play nice with the Nest.

[ronsin1]

once you could trigger the relays on the circuit board to match the sequences it normal uses anything is possible

[Rainman]

Already decided to go with splits. I got a quote for 275k today For that i can put in a pool.

[cinco]

Already decided to go with splits. I got a quote for 275k today For that i can put in a pool.

It even have electricity where u building?

[TriniAutoMart]

airuma, this is the ole talk section, but we have lots of people here with industry experience in many different fields. AC systems is one of them. Can you tell us where you can get a "36,000 btu that operates on single phase" and is that for the AHU and the chiller sections?

As with all trades, some craftsmen have different experiences and preferences. I would assume that alex jj meant that one unit could be put out of commission and leave the other working while the compressor is running rather than letting one just run properly while the other one makes ice and sweating water.

I believe that the 36,000 BTU split units work on normal residential connections.

[ronsin1]

Need to start painting fences yes

[Rainman]

Need to start painting fences yes

[RBphoto]

Champagne taste.. mauby pocket.

[wheelbarrow]

https://www.sensibo.com allyuh check that out. Looks like an option for split units.

[QM]

Hi, Just a bump. A few years later.

Who is the best company to call for a central system? Need about 30 tones of cooling.

[nervewrecker]

Hi, Just a bump. A few years later.

Who is the best company to call for a central system? Need about 30 tones of cooling.

What kinda area you looking to cool?

I assume is ducted you looking at?

Bear in mind a central 30 tonne system is a piece of money plus duct work. Most places seem to be going the disposable duct way as not much companies do duct cleaning so maintenance can be an issue esp since most like to chinks on servicing or pay cheap price for halfway job.

You looking at in excess of $100k

Decent 5 tonne mini split could cost you approx $15k installed so multiply that by 5. With that option, you can turn off some if you dont have the heat load for it.

[j-honda-civic]

Hey give these guys a call they are very professional,They will give you the best advice ....799-7043

[QM]

Hi, Just a bump. A few years later.

Who is the best company to call for a central system? Need about 30 tones of cooling.

What kinda area you looking to cool?

I assume is ducted you looking at?

Bear in mind a central 30 tonne system is a piece of money plus duct work. Most places seem to be going the disposable duct way as not much companies do duct cleaning so maintenance can be an issue esp since most like to chinks on servicing or pay cheap price for halfway job.

You looking at in excess of $100k

Decent 5 tonne mini split could cost you approx $15k installed so multiply that by 5. With that option, you can turn off some if you dont have the heat load for it.

Office area, with at least 5 individual temp zones. So I was thinking 5 individual sets of ducting, 5 air handlers and maybe 2 VRF condensers. ( 2 condensers to be redundant.)

Main reason for interest in ducted system is no need for service men to enter. They can do everything from outside.

[nervewrecker]

Depending on the system, conventional fixed flow type evaporators aren't used with vrf condensers. Im not saying there aren't but to my knowledge there is a solenoid type metering device. Not sure of there are fixed flow type evaps for commercial vrf systems.
Eventually they will need to clean the ducts. And that's way more invasive and intense than the conventional service.
Ducted systems can however be a lot neater and discrete.

[QM]

Depending on the system, conventional fixed flow type evaporators aren't used with vrf condensers. Im not saying there aren't but to my knowledge there is a solenoid type metering device. Not sure of there are fixed flow type evaps for commercial vrf systems.
Eventually they will need to clean the ducts. And that's way more invasive and intense than the conventional service.
Ducted systems can however be a lot neater and discrete.

Thank you for the information.

[nervewrecker]

So happens I had to give an estimate on a pair of 20 tonnes.

It's about $200k without transport and ducting work.

So just a ball park figure of what you looking at. Non vrf

Meanwhile a good 5 tonne may cost you about $15k installed.

[rspann]

Had a 18000 Pioneer installed this week but I find it not biting at all. They came back twice and checked it . The second time they vacuumed all the gas it came with and re-gassed. I find it still not as cold as it should be. What to tell them to do? Another room has a 18000 innovair and that thing does feel like the artic.

[nervewrecker]

Had a 18000 Pioneer installed this week but I find it not biting at all. They came back twice and checked it . The second time they vacuumed all the gas it came with and re-gassed. I find it still not as cold as it should be. What to tell them to do? Another room has a 18000 innovair and that thing does feel like the artic.

Which innovair?

Older innovair, peake and miller were the same units. Tanks.

Recent models may have been slightly different from the pioneer wit the pioneer being the cheapest and possibly the smallest but right now, all is the same.

What size is the room though?

Something wrong if the vaccume the refrigerant. Unless they recover it, vaccume and recharge it with a fresh charge. Did they charge by weight, pressure, current draw or a combination of which two? R410 refrigerant seems to be one that a lot of techs dont know their way around and they like to charge via pressure. Of course I am not going to elaborate for men to read and learn here.
I have not a clue why they will pump down and vacume back though.
Did they use a vaccume pump initially and how big is the room?

[rspann]

The room is 17x 21. the installer called the supplier and was told to do what he did . The one that was replaced was cold and nice but had an on and off water leak which I got fed up of and seeing that I had new ones intalled right through the house ,I decided to change out this one too.

Like I getting senile. Is not innovairs is Lennox right through. The usual guy was doing some big job and putting me off so I used this one who services for my mom.

[nervewrecker]

The room is 17x 24, the installer called the supplier and was told to do what he did .

I think he didn't understand what they said when he called them. They meant 2 18000 btu.

Men putting down ac and still cant estimate heat load. De f**k you calling someone to ask what size unit and you installing?

I gauged two sites by eye today and the estimates were spot on when I ran it by the manager for the company.

Two 20 tonne for one and two 5 tonne for the other. Both ducted and 3 phase.

[rspann]

No, they told him to try vacuuming and recharge and if that doesn't work they will replace the unit. He was the one who said 18000. The other thing is this room is downstairs a big building at almost the center and gets no direct sun, so it isn't hot even without A/C.

[nervewrecker]

No, they told him to try vacuuming and recharge and if that doesn't work they will replace the unit. He was the one who said 18000. The other thing is this room is downstairs a big building at almost the center and gets no direct sun, so it isn't hot even without A/C.

I does wonder if some of these people know anything about what they selling.
Them and all didn't ask questions? They recommend purging refrigerant and charging back?
And willing to replace if it don't cool?
Which company is this? I like their sales ethic.

[QM]

So happens I had to give an estimate on a pair of 20 tonnes.

It's about $200k without transport and ducting work.

So just a ball park figure of what you looking at. Non vrf

Meanwhile a good 5 tonne may cost you about $15k installed.

Thank you.

Do you have any duct men you could recommend?