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Air conditioning - Any recommendations please??

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Old 23-11-2016, 04:45 PM   #8731
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Normally, there are many factors that can affect the cooling of the room. It will be good to check the temperature of the cooling fins in the FCU as reference. Then compare that with the standard temperature of your model. This way, the performance of the air conditioner can be assessed. You can search the model for the standard temperature at the FCU fins or call Mitsubishi for help on this temperature. Check should also be made to ensure that the air flow from the FCU is accordance to the specification.

Working on "feeling" can be difficult to resolve. I suggest that payment should not be made yet. There are cases when during installation, workers skipped the air purging and leakage check which can affect the effectiveness of the system and future costly defects.

The above are my option and I hope it is helpful. I feel that it may be better to pay a little bit more to have an authorization dealer so that in the event of a dispute, you still have an upper hand to call the company to review the case.




I called my aircon installer and he advised me when testing, don't turn on 18 deg at the start for all 3 rooms (2x common rooms and master room), because the compressor is unable to support all at once. He told me I should turn on for example the first room at 21 deg, then wait for a few mins, then turn on the second room at 23 deg, wait for another few mins, then turn on the third room at maybe 25 deg.

I'm going to test my new mitsubishi electric aircon tonight again to try out his method..

@dachee, do you mean I need to check out on this pdf regarding the cooling fins? Looks very chim sia..
http://www.mitsubishielectric.com/se...ls/cooling.pdf

or this one from GAin city?

https://www.gaincity.com/media/catal...talogues_3.pdf
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Last edited by hahnhahnhahn; 23-11-2016 at 04:49 PM..
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Old 23-11-2016, 08:29 PM   #8732
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To boopit,

This price seems reasonable.
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Old 23-11-2016, 08:32 PM   #8733
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To hahnhahnhahn,

The way your aircon guys asked you to on the rooms one by one with different temp is technically making no sense.
The compressor is max at 30k btu, his quote states 24k btu.
Even if you on 12k + 9k + 9k = 30k, no issues at all.
The compressor will just operate at Full Load.

If you wish to measure the temp of the air flowing out from the aircon blower, it should be < 15 degrees.

Last edited by terumo; 23-11-2016 at 08:33 PM.. Reason: Typo
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Old 23-11-2016, 08:39 PM   #8734
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I called my aircon installer and he advised me when testing, don't turn on 18 deg at the start for all 3 rooms (2x common rooms and master room), because the compressor is unable to support all at once. He told me I should turn on for example the first room at 21 deg, then wait for a few mins, then turn on the second room at 23 deg, wait for another few mins, then turn on the third room at maybe 25 deg.

I'm going to test my new mitsubishi electric aircon tonight again to try out his method..

@dachee, do you mean I need to check out on this pdf regarding the cooling fins? Looks very chim sia..


or this one from GAin city?
Hi, Have a look at the gaincity mitsubishi catalogues and you will notice the following specification at the bottom of page 29:

Indoor Outdoor
(Different Indoor Model) (Different Outdoor Model)
Cooling : Upper limit 21degree C DB/15degree C WB -10degree C DB
Lower limit 32degree C DB/23degree C WB 46degree C DB

Then read the note below this table in the catalogue.

Sorry, cannot tabulate the texts above.

What the table is saying (if I am not wrong) is that at the upper limit with outside dry bulb temperature (ie normal thermometer temperature) of -10 degree C at the compressor incoming air flow, you will be able to get 21 degree C using a thermometer or 15 degree C with a wet bulb thermometer in the room (normally near the FCU) with airflow set at maximum. Similarly the reading for the lower limit and also what is written on the note below the table in the catalogue.

You may noticed that none of them indicates a dry bulb temperature of 18 degree C. And that is why I asked the question earlier whether 18 degree C is what you want because most air conditioner in Singapore if I am not wrong is unable to reach that temperature. if not wrong the system should ran for 2hours before checking.

The above are my opinion, I hope that it is useful.

Last edited by dachee; 23-11-2016 at 08:47 PM..
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Old 23-11-2016, 08:52 PM   #8735
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To hahnhahnhahn,

The way your aircon guys asked you to on the rooms one by one with different temp is technically making no sense.
The compressor is max at 30k btu, his quote states 24k btu.
Even if you on 12k + 9k + 9k = 30k, no issues at all.
The compressor will just operate at Full Load.

If you wish to measure the temp of the air flowing out from the aircon blower, it should be < 15 degrees.
I agreed with terumo that the contractor's recommendation is not appropriate. I don't think Mitsubishi will agrees to it too.

Last edited by dachee; 23-11-2016 at 08:57 PM..
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Old 23-11-2016, 09:07 PM   #8736
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To hahnhahnhahn,

Looking at the 2 system configurations that you provided, can it really work? Can you really have a total indoor load more than your outdoor unit? I think there will be some kind of compromise in efficient / cooling.

Last edited by dachee; 23-11-2016 at 09:38 PM..
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Old 23-11-2016, 10:28 PM   #8737
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thanks terumo and dachee. also feel that living room needs more than 9k BTU.

I got a new quote:

Daikin inverter system 4 smile series
MKS80QVMG/CTKS25QVM x3 , CTKS50QVM x1
3/8" armaflex insulation (individually insulate)
pure SWG22
16mm pipe with insulation
keystone 3C40/3C70
siroflex sealant
nashua duct tape

$4299

and
Mitsubishi electric starmax inverter system 4 (5 ticks)
MXY4G28VA, MSXFJ10VE X3, MSXYFJ18VE X1
$4499 (the specs same as the above daikin)

what's your opinion?
Hi, Why do you said that the spec are the same. 1) Even for 5 ticks, their consumption are not the same, so are the operating cost. 2) What about the sound level as lowest and full fan?, 3) how about the air flow rate? 4) though, most FCU indicates 9k but what is their actual rating? 5) similarly for the compressor, don't just look at the round number, look at the actual spec rating. 6) you may also wish to check the outdoor unit sound level. 7) and cost as well as warranty. Once you get all these figures, list them in priority of your choice to select which system is suitable for you.

The above are just my opinion. Hope that it is helpful.
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Old 23-11-2016, 11:46 PM   #8738
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To hahnhahnhahn,

The way your aircon guys asked you to on the rooms one by one with different temp is technically making no sense.
The compressor is max at 30k btu, his quote states 24k btu.
Even if you on 12k + 9k + 9k = 30k, no issues at all.
The compressor will just operate at Full Load.

If you wish to measure the temp of the air flowing out from the aircon blower, it should be < 15 degrees.
Well, just now I tried as per what the aircon man suggested. But when I on the third room, all 3 rooms became not cold. I'm going to get him to check again.

Thanks for pointing out the max load of 30k. This was shared by him also when he came on-site survey. I totally forget about this
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Old 23-11-2016, 11:50 PM   #8739
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To hahnhahnhahn,

Looking at the 2 system configurations that you provided, can it really work? Can you really have a total indoor load more than your outdoor unit? I think there will be some kind of compromise in efficient / cooling.
dachee, thanks for pointing out. I engaged this aircon installer because I thought my ID recommended one will be good. I'm going to get him to check thoroughly again before making any payment.

Conclusion, I spent three nights test run the aircon and they really are not cold, especially when I on the third room (master room)
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Old 24-11-2016, 12:05 AM   #8740
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Hi, Have a look at the gaincity mitsubishi catalogues and you will notice the following specification at the bottom of page 29:

Indoor Outdoor
(Different Indoor Model) (Different Outdoor Model)
Cooling : Upper limit 21degree C DB/15degree C WB -10degree C DB
Lower limit 32degree C DB/23degree C WB 46degree C DB

Then read the note below this table in the catalogue.

Sorry, cannot tabulate the texts above.

What the table is saying (if I am not wrong) is that at the upper limit with outside dry bulb temperature (ie normal thermometer temperature) of -10 degree C at the compressor incoming air flow, you will be able to get 21 degree C using a thermometer or 15 degree C with a wet bulb thermometer in the room (normally near the FCU) with airflow set at maximum. Similarly the reading for the lower limit and also what is written on the note below the table in the catalogue.

You may noticed that none of them indicates a dry bulb temperature of 18 degree C. And that is why I asked the question earlier whether 18 degree C is what you want because most air conditioner in Singapore if I am not wrong is unable to reach that temperature. if not wrong the system should ran for 2hours before checking.

The above are my opinion, I hope that it is useful.
Thanks for the pointer, guess worse case scenario I will have to take a thermometer and stand infront of the aircon le.. didn't know aircon test run can be so tedious.. sob sob
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Old 24-11-2016, 12:17 AM   #8741
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To hahnhahnhahn,

Good, have a check again on the loading. If need to change, at least the change unit is not registered yet with the manufacturer. The aircon will stay with you for many years, so need to get it right from the start.
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Old 24-11-2016, 12:42 AM   #8742
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To hahnhahnhahn,

Good, have a check again on the loading. If need to change, at least the change unit is not registered yet with the manufacturer. The aircon will stay with you for many years, so need to get it right from the start.
Okay understand.. currently I think the aircon installer is still sincere to assist me as of now. I've already prepare the cheque about a week ago, but just can't pay them given the current state.. just wondering if I shld make a 50% payment first and meanwhile have them check on it
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Old 24-11-2016, 10:41 AM   #8743
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Okay understand.. currently I think the aircon installer is still sincere to assist me as of now. I've already prepare the cheque about a week ago, but just can't pay them given the current state.. just wondering if I shld make a 50% payment first and meanwhile have them check on it
Hi, I did some check on your configuration. You have 2XGE10+GE13+GE24, meaning 2X9K+12K+24K btu/hr = 54k btu/hr or 15.8KW. This is above the specification of total capacity of all indoor unit must not exceed 15.6kW as indicated in Mitsubishi catalogue page 12 for MXY-4A28VA.

I understand that this configuration is provided by Mitsubishi as 10+10+13+24 in their catalogue on page 18. However, with this configuration Mitsubishi also indicated that the capacity of each FCU will then be 1.39+1.39+1.39+3.03=7.2kW. 7.2kW is only 24.5k btu/hr. This is the max. capacity of your outdoor as specified in page 18. You may noticed that all your indoor unit is now under capacity. The 10VA should have 2.5kW (or 8.9k btu/hr) but now is only 1.39kW (4.7k btu/hr) ie, it is only able to remove half the amount of heat that it is designed to do so. Notice that for the 10VA to run at 2.5kW, Mitsubishi indicated that only one FCU is suppose to be running (ie single unit running). Similarly, the other FCUs, 13VA and 24VA are all operating under capacity. When running as single unit, the 13VA is 3.5kW or 11.9k btu/hr but running at only 4.7k btu/hr and the 24VA is 6kw or 24.5k btu/hr but running at only 10.3k btu/hr

Meaning though you may have followed the Mitsubishi configuration, it does not give you total capacity output.

The above are my opinion and hope that it is helpful.

Last edited by dachee; 24-11-2016 at 03:53 PM..
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Old 24-11-2016, 03:55 PM   #8744
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Hi, I did some check on your configuration. You have 2XGE10+GE13+GE24, meaning 2X9K+12K+24K btu/hr = 54k btu/hr or 15.8KW. This is above the specification of total capacity of all indoor unit must not exceed 15.6kW as indicated in Mitsubishi catalogue page 12 for MXY-4A28VA.

I understand that this configuration is provided by Mitsubishi as 10+10+13+24 in their catalogue on page 18. However, with this configuration Mitsubishi also indicated that the capacity of each FCU will then be 1.39+1.39+1.39+3.03=7.2kW. 7.2kW is only 24.5k btu/hr. This is the max. capacity of your outdoor as specified in page 18. You may noticed that all your indoor unit is now under capacity. The 10VA should have 2.5kW (or 8.9k btu/hr) but now is only 1.39kW (4.7k btu/hr) ie, it is only able to remove half the amount of heat that it is designed to do so. Notice that for the 10VA to run at 2.5kW, Mitsubishi indicated that only one FCU is suppose to be running (ie single unit running). Similarly, the other FCUs, 13VA and 24VA are all operating under capacity. When running as single unit, the 13VA is 3.5kW or 11.9k btu/hr but running at only 4.7k btu/hr and the 24VA is 6kw or 24.5k btu/hr but running at only 10.3k btu/hr

Meaning though you may have followed the Mitsubishi configuration, it does not give you total capacity output.

The above are my opinion and hope that it is helpful.
Meaning to say what they display is just words and figures but cannot be attained in real life unless only 1FCU is operating at one time
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Old 24-11-2016, 04:50 PM   #8745
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Hi, I did some check on your configuration. You have 2XGE10+GE13+GE24, meaning 2X9K+12K+24K btu/hr = 54k btu/hr or 15.8KW. This is above the specification of total capacity of all indoor unit must not exceed 15.6kW as indicated in Mitsubishi catalogue page 12 for MXY-4A28VA.

I understand that this configuration is provided by Mitsubishi as 10+10+13+24 in their catalogue on page 18. However, with this configuration Mitsubishi also indicated that the capacity of each FCU will then be 1.39+1.39+1.39+3.03=7.2kW. 7.2kW is only 24.5k btu/hr. This is the max. capacity of your outdoor as specified in page 18. You may noticed that all your indoor unit is now under capacity. The 10VA should have 2.5kW (or 8.9k btu/hr) but now is only 1.39kW (4.7k btu/hr) ie, it is only able to remove half the amount of heat that it is designed to do so. Notice that for the 10VA to run at 2.5kW, Mitsubishi indicated that only one FCU is suppose to be running (ie single unit running). Similarly, the other FCUs, 13VA and 24VA are all operating under capacity. When running as single unit, the 13VA is 3.5kW or 11.9k btu/hr but running at only 4.7k btu/hr and the 24VA is 6kw or 24.5k btu/hr but running at only 10.3k btu/hr

Meaning though you may have followed the Mitsubishi configuration, it does not give you total capacity output.

The above are my opinion and hope that it is helpful.
dachee, meaning to say..given this Mitsubishi Electric system 4 aircon in my new place.. what i experienced (all rooms became not cold when the third room was turn on) is expected and correct?

in other words, my compressor is actually not able to provide enough cold air to all 3 rooms...? So turning on 2 rooms aircon tgt is actually no issue one right?

thanks for your detailed explanation... =)
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