Air conditioning - Any recommendations please?? - Part 2

[UchihaSasuke]

Thank you, very informative! Indeed i find many sellers passing off standard requirements for R32 as “premium”. Worse are those that insist its optional top-up (unethical, avoid!).

i started off wrongly as the first seller didnt advise me correctly on the cooling power (btu) required. Now after a few days of furious exchanging of whatsapp with different sellers and speaking to me (trusted) AC servicing guy i have arrived at the below set up for my case :

ME Starmex
FC : 2 X FP13VG / Outdoor : 3H28
FC : FP13VG + FP18VG / Outdoor : 4H33

Inclusive new pipes :
+ 16mm drain pipe
+ 4C40 + 3C70 keystone cables
+ 3/4” class ‘0’ Armaflex
+ SWG21 copper pipe (thailand)
+ 2 trips installation

Awaiting final quote(s) before deciding which seller

I can say for sure with "FC : FP13VG + FP18VG / Outdoor : 4H33" it will past above the rated capacity, unless you only switch on 1 at a time.

I am using system 4 with 33vg, at any point of time, the maximum i used is 10vg and 18vg, and that is already above the rated capacity.

 

[hkchew03]

I can say for sure with "FC : FP13VG + FP18VG / Outdoor : 4H33" it will past above the rated capacity, unless you only switch on 1 at a time.

I am using system 4 with 33vg, at any point of time, the maximum i used is 10vg and 18vg, and that is already above the rated capacity.

Above rated is actually non issue, once the room is cooled, the FCU will not be running at full capacity and will go below the rated, unless you trying to run very low temperature on a very hot afternoon or constant opening of doors etc. The 2 FCU mentions combine rating is still well below a 4H33 peak. Pretty much all split system are design and sold in a way that the compressor rating is below the rating of all FCU combined. Otherwise you will need to pair a 4H38 or even 5H48 for any system 2 with FP18.

 

[petetherock]

If you have two 18k blowers working at the same time you’re killing that 33k compressor

 

[alannn]

The short answer is Yes. If the night weather is cool, then it is ok. If it is hot, you are likely to complain one of the rooms is not cold.

The worse is when u pick a 20k rated BTU compressor.

It is never ideal that you intend to have 2 compressors but pair all 3 FCUs for Bedroom to 1. There are many issues. First, your FCU for living room and dining room, if pair to 1, will suffer. 2nd, you just wasting the money spent on buying a 2nd compressor.

IF you only getting one compressor, this is because of circumstances, at least get the 25k rated BTU compressor. Many in the market when selling system 3, only give you the 20k rated BTU compressor.

So, how cold you want depends on how much you want to spend.

On the other hand, since both are inverter and the load is not high for each compressor. The electricity bill may not be high.

To be honest, i feel there isn't much difference in the bills. It is not like you see double the cost. For e.g i turn on my living room and dining area, supported by 2 compressors, for 8 hours THe monthly electricity bill is about $120. i don't think is very far off from just turning one compressor.

After taking into accounts of all the advices from this forum, I have finally come to the conclusion for my aircon setup and specs.

Material specs :
1) SW21 Copper Pipe (Made in Thailand)

2) 3/4” insulation - Armaflex CX Shield OR K Flex split twin.
From what I read up so far, this insulation seems more for extra protection on the part in the outdoor section leading to Condenser. Is it overkill to ask for all insulation indoor with this

3) 4C40 (outdoor) + 3C70 (indoor) keystone cables (made in SG)

4) 16mm drain pipe wth insulation

Installation requirement :
-All insulation joint to be glued before duct tape
-Dual layer trunking to be use where neccessary to prevent over conjestion of pipings with 3/4" insulation
-All drain pipes to be fully insulated especially at corners
-All copper pipe to be insulated individually and NOT combine into a single insulation
-Purge, vacuum and recharge gas

Aircon configuration

1 set of system 2 (Blue)
1 set of system 3 (Green)

System 2 for :
Living - 12K
Master Bedroom - 12K
Condenser - MXY-4H33VG (6.9kW) - normal rated 23.5K

Usage pattern
Will turn on only Master at night
Will turn on Living for family use occasionally in the day
Will only on both if guest sleepover at living at night
From the condenser i looking at , it is only slightly under power if turn both, will it be a concern in view of my pattern of usage?

System 3
Bedroom 1 - 9K
Bedroom 2 - 9k
Dining - 18K
Condenser - MXY-4H33VG (6.9kW) - normal rated 23.5K

Usage pattern
Will turn on both bedroom for the night
Will turn on Dining occasionally during day or evening
Will on Dining room and 1 bedroom occasionally
Will very very rarely turn on all at the same time

Summary
2 condenser will be turn on every night to cool all the bedrooms - hopefully will not translate into too high a electrical bill

looking forward for any comment on anything i may have overlook! Brand wise, honestly , i still having a hard time deciding ( Starmex, Pana, Youme & Daikin)

 

[abkt99]

A question about the cables. Installer says that :
4C40 is indoor to outdoor
3C70 is compressor to isolator
But I'm using a 15amp power point with no isolator. Does that mean that the 3C70 is not required?

 

[hwmook]

ask the shop/company to revise quote to include below list of material (this is the true “premium” option) :
1) 16mm drain pipe (standard for all sellers)
2) 4C40 (outdoor) + 3C70 (indoor) cables (made in SG)
3) 3/4” insulation (class ‘0’ at least for outdoor; shielded as suggested by another forumer)
4) SWG21 copper pipe (thailand)
5) 2 trips installation

#1 may not be applicable if you reusing existing drain, #2 is included in your quote posted so #3 and #4 are the “upgrades” in your case

reject made in china (MIC) materials.

You guys are getting more and more crazy about the installation material. SWG22 + 1/2 inch insulation is good enough already. The compressor will fail before you have problems. There are still companies doing standard installation using SWG23 + 3/8inch insulation.

 

[The_King]

You guys are getting more and more crazy about the installation material. SWG22 + 1/2 inch insulation is good enough already. The compressor will fail before you have problems. There are still companies doing standard installation using SWG23 + 3/8inch insulation.

Some of the installation material is manufacturer requirements

My old post I say there manufacturer requirements vs vendor recommendation to follow who is right or wrong I dont know. Maybe both wrong or both right I dont know


The main concern is the workmanship, many ac problem is due to poor workmanship.

Anyway I not worry about compressor spoil more afraid of PCB spoil which kena charge a like 600 to $800 range

 

[lousylah]

You guys are getting more and more crazy about the installation material. SWG22 + 1/2 inch insulation is good enough already. The compressor will fail before you have problems. There are still companies doing standard installation using SWG23 + 3/8inch insulation.

From what i read, its been less than 1yr since the mandatory use of R32 “gas” in Singapore. R32 has stricter requirements on the materials.

So all the built-up knowledge on install materials from before 2023 are no longer relevant - thats the key!

do some web research on your own and you will find that overseas the recommend gauge (not grade as commonly mistaken in sg) is 21 or 0.81mm thickness for R32.

i suspect shops and installer are stuck with old stock or supplier/supply chain still WIP thus just sticking to “current arrangement” (e.g. “we do for so many yrs, no problem!” argument). In a way they are clearing old stock. I think NEA/BCA are aware and not being too restrictive such that it kills off too many SMEs.

so the market will need time to adjust - both sellers/vendors/installers and end-consumer knowledge. I also only realised myself just in the pass 7 days - what i knew from my previous reno was no longer relevant.

 

[mark lim]

Above rated is actually non issue, once the room is cooled, the FCU will not be running at full capacity and will go below the rated, unless you trying to run very low temperature on a very hot afternoon or constant opening of doors etc. The 2 FCU mentions combine rating is still well below a 4H33 peak. Pretty much all split system are design and sold in a way that the compressor rating is below the rating of all FCU combined. Otherwise you will need to pair a 4H38 or even 5H48 for any system 2 with FP18.

The compressor of today are not like the past inverters. All are throttled to achieve the 4-5star rating that NEA imposes. No magic formula. Cut capacity to cut power usage.

 

[mark lim]

After taking into accounts of all the advices from this forum, I have finally come to the conclusion for my aircon setup and specs.

Material specs :
1) SW21 Copper Pipe (Made in Thailand)

2) 3/4” insulation - Armaflex CX Shield OR K Flex split twin.
From what I read up so far, this insulation seems more for extra protection on the part in the outdoor section leading to Condenser. Is it overkill to ask for all insulation indoor with this

3) 4C40 (outdoor) + 3C70 (indoor) keystone cables (made in SG)

4) 16mm drain pipe wth insulation

Installation requirement :
-All insulation joint to be glued before duct tape
-Dual layer trunking to be use where neccessary to prevent over conjestion of pipings with 3/4" insulation
-All drain pipes to be fully insulated especially at corners
-All copper pipe to be insulated individually and NOT combine into a single insulation
-Purge, vacuum and recharge gas

Aircon configuration

1 set of system 2 (Blue)
1 set of system 3 (Green)

System 2 for :
Living - 12K
Master Bedroom - 12K
Condenser - MXY-4H33VG (6.9kW) - normal rated 23.5K

Usage pattern
Will turn on only Master at night
Will turn on Living for family use occasionally in the day
Will only on both if guest sleepover at living at night
From the condenser i looking at , it is only slightly under power if turn both, will it be a concern in view of my pattern of usage?

System 3
Bedroom 1 - 9K
Bedroom 2 - 9k
Dining - 18K
Condenser - MXY-4H33VG (6.9kW) - normal rated 23.5K

Usage pattern
Will turn on both bedroom for the night
Will turn on Dining occasionally during day or evening
Will on Dining room and 1 bedroom occasionally
Will very very rarely turn on all at the same time

Summary
2 condenser will be turn on every night to cool all the bedrooms - hopefully will not translate into too high a electrical bill

looking forward for any comment on anything i may have overlook! Brand wise, honestly , i still having a hard time deciding ( Starmex, Pana, Youme & Daikin)

Wonder why 13k for living and 18k for dining. The calculated btu is only 1k difference.
I would also put the blower for bedroom1 above the door. Then you can place a wardrobe or cabinets. With the blower over the door, you won’t have to shift furniture to service it or when any dripping it won’t wet stuff. The room is small enough not to matter too much on blower placement for efficiency.

 

[lousylah]

From what i read, its been less than 1yr since the mandatory use of R32 “gas” in Singapore. R32 has stricter requirements on the materials.

So all the built-up knowledge on install materials from before 2023 are no longer relevant - thats the key!

do some web research on your own and you will find that overseas the recommend gauge (not grade as commonly mistaken in sg) is 21 or 0.81mm thickness for R32.

i suspect shops and installer are stuck with old stock or supplier/supply chain still WIP thus just sticking to “current arrangement” (e.g. “we do for so many yrs, no problem!” argument). In a way they are clearing old stock. I think NEA/BCA are aware and not being too restrictive such that it kills off too many SMEs.

so the market will need time to adjust - both sellers/vendors/installers and end-consumer knowledge. I also only realised myself just in the pass 7 days - what i knew from my previous reno was no longer relevant.

Australia
https://www.industry.gov.au/sites/d...ube_to_asnzs_1571_-_mm_kembla_-_applicant.pdf

New Zealand
https://www.kembla.co.nz/Portals/0/Products/Brochures/ASNZS1571 Refrigeration & Med Gas Brochure.pdf

United Kingdom
https://www.toshiba-aircon.co.uk/wp...30_R32_MIRAI_RAS-24BKVG-E_RAS-24BAVG-E_EN.pdf

All the above indicate minimum/recommended 0.8mm thickness copper piping (SWG21) for R32.

are these countries “crazy” or are we (sg) complacent? what do you guys think? You decide.

I dont think anyone of us in this forum is qualified enough to know for sure. But i will go for majority (bigger countries, larger population elsewhere) can stick to Gauge 21 copper.

 

[alannn]

Wonder why 13k for living and 18k for dining. The calculated btu is only 1k difference.
I would also put the blower for bedroom1 above the door. Then you can place a wardrobe or cabinets. With the blower over the door, you won’t have to shift furniture to service it or when any dripping it won’t wet stuff. The room is small enough not to matter too much on blower placement for efficiency.

Thanks Mark!, And thanks for pointing out the FCU position for bedroom 1.My current FCU position is above the door but more to the left side, no problem with that in fact. My proposed new position is just to shorten the trunking length which will be routed out to the dining . But yes looking at it now, putting above door will be just as good though. Obstruction wise, will not affect as that area will just be study table.

As for the 18K FCU for dining. My thinking was that at times when weather is not so hot and in the evening, I just need to on the 18K alone to cool down both Living and dining. Just that flexibility in mind, as my family are the type comfortable with 25-26 degree temp.

 

[The_King]

Australia
https://www.industry.gov.au/sites/d...ube_to_asnzs_1571_-_mm_kembla_-_applicant.pdf

New Zealand
https://www.kembla.co.nz/Portals/0/Products/Brochures/ASNZS1571 Refrigeration & Med Gas Brochure.pdf

United Kingdom
https://www.toshiba-aircon.co.uk/wp...30_R32_MIRAI_RAS-24BKVG-E_RAS-24BAVG-E_EN.pdf

All the above indicate minimum/recommended 0.8mm thickness copper piping (SWG21) for R32.

are these countries “crazy” or are we (sg) complacent? what do you guys think? You decide.

I dont think anyone of us in this forum is qualified enough to know for sure. But i will go for majority (bigger countries, larger population elsewhere) can stick to Gauge 21 copper.

well said

thumb up

 

[UchihaSasuke]

I just finished my air con installation few days back.

The only thing i change is SWG 22 to SWG 21.

For insulation, at first i do want to upgrade my insulation to 3/4 inch, but after some thought plus researching and speaking to quite a few installer, 1/2 inch armaflex is enough for me and it is indoor with trunking, so i ditch the idea of upgrading to 3/4 inch.
I also must make clear that i do have space constraint for my routing, 3/4 inch will be very challenging, as my 1/2 inch routing, my installer spent quite a considerable amount of time pulling, arranging and packing them nicely and properly into the trunking.

For myself, i believe the rest below should be the standard or at least minimum requirements.
Insulation 1/2 inch AND individual insulation per piping, e.g. system 4, 8 copper piping insulated individually, system 3 will be 6 etc...
16mm drainage pipe
3C40 (indoor) and 3C70 (outdoor) Keystone (Made in Singapore)
R32, yes, i know this should be already in place, but during the course of searching for air con installer, i encounter people offer R410 and say not much different than R32.

 

[hkchew03]

The compressor of today are not like the past inverters. All are throttled to achieve the 4-5star rating that NEA imposes. No magic formula. Cut capacity to cut power usage.

H33 is already rated at 6.9kW with peak at 10.7kW, FP13+18 is only rated to 8.5kW. If one really want to accommodate all FCU with just rated compress, you will need 5H48 which doesn't make sense unless you have no concern for money.

 

[mark lim]

Thanks Mark!, And thanks for pointing out the FCU position for bedroom 1.My current FCU position is above the door but more to the left side, no problem with that in fact. My proposed new position is just to shorten the trunking length which will be routed out to the dining . But yes looking at it now, putting above door will be just as good though. Obstruction wise, will not affect as that area will just be study table.

As for the 18K FCU for dining. My thinking was that at times when weather is not so hot and in the evening, I just need to on the 18K alone to cool down both Living and dining. Just that flexibility in mind, as my family are the type comfortable with 25-26 degree temp.

I would just put 18k for both if the extra isn’t much. If you see the Mitsubishi catalog , at the lowest consumption both 13k and 18k is the same. Thus both consume the same power when the set temp is reached. But you get more capacity at the top with 18k during initial cooling. That’s the advantage of the inverter system.
my take is that I will switch on both for max cooling and then once temp is reached, maybe can shut off one unit. Cause if you switch on for 4-5hrs at night. You want it cool asap. Else if it takes 1hr to cool down the space then you really only get to enjoy the coolness for less time.
But most importantly remove the silly current limiter. Else your units of 33btu will perform like a 28btu

 

[007Mi6]

May I know how much power does a R32 5 Tick uses for 3x 9K BTU every night?

 

[The_King]

May I know how much power does a R32 5 Tick uses for 3x 9K BTU every night?

Check NEA websites

 

[alannn]

May I know how much power does a R32 5 Tick uses for 3x 9K BTU every night?

I happened that last few days out of curiosity I monitored my electrical usage by keeping track of the meter reading every 12hours and this is what I have recorded,

Current 10 years old aircon system 3 3x9KBTU
Turn on aircon from 8pm till morning 7pm ( 2 aircon - 16kWh , 3 aircon - 24kWh )
(Bear in mind reading taken was with the usual home stuff turned on like lighting, PC and fridge and TV)
While in the day time, as I WFH alone, without aircon, i recorded about average 6kWh for period from 8am-8pm.
So from there i can roughly gauge how much power my aircon used. As I will be replacing my aircon soon to a system 3+2. and my new configuration will involve turning on 2 condenser for same usage pattern as before. By then will be able to keep track of new system vs the old.

 

[cdo_saturday]

How does one identify if the insulation is 1/2” besides measuring the thickness physically? I was quoted 1/2” insulation but the numbers on the insulation (3/8”) (1/4”) refers to the cu pipe thickness am I right?

edit: added photo