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problem with split a/c
thanks guys for your info on pipe flareing.
I have a prob with a split a/c. there is no cooling or heating happening inside. when in cooling, the liquid pipe outside and where it connects to the outside unit gets very frosty. when in heating the gas pipe gets very hot , but nothing happeing inside.
Have I lost gas? Does that mean Ive lost oil aswell?
(im a sparky, but im learning) thanks
paul
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hi paul,
gas is missing and maybe a little oil.
find the leak, (usually ,the frair cups) top it up, make sure not tto much, and there you go.
in second thought, check that cup tube is not blocked,
you can do it by adding gas and see if suction temp. got higher.
good luck.
chemi
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Also, is the indoor coil fan operating? you can get the same effects as a shortage of gas if you are only looking at the pipes
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[find the leak, (usually ,the frair cups) top it up, make sure not tto much, and there you go.]
DON'T JUST TOP UP
1, reclaim
2, repair
3, evacuate
4, re-charge with refrigerant
:cool:
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of course you right jasper.
I took it for granted that these steps are known and practiced.
chemi :o
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Thanks Chemi and Jasper.
I followed all these steps with the help of a friend who is an air con mechanic. Everything is fine now, however Im alittle worried that it might be slightly undercharged. When we were adding gas, we ran out to the point that we had to heat up his bottle to get alittle more out of it.
It is showing SLIGHT symptoms like it was before. We made sure there is no leak now. I was thinking that maybe i could get some more gas and a set of gauges and put alittle more in. How do I know how much? is it bad if i put too much in?
Any thoughts guys?
Paul
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which gas is it running on:confused: :confused:
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what is the make and model of the unit.
what is the pipe run length (one way)
:confused: :confused:
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Hi Jasper,
Its a Daikin Inverter 2.5 Hp split
R22
and pipe length is about 4m 1 way. Basically a back to back installation.
Also I was wondering is there a way I can check how much is on there now just buy using a set of gauges?
Cheers
Paul
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On a Daikin Inverter split you must charge by weight only the amount stated on the unit. The factory charge is good for 30m of pipework. You CANNOT charge any other way as you do not know how loaded or unloaded the compressor is when charging. You certainly can't charge to a back pressure reading, or an amp draw.
Is it R407C or R410a?
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Hi Frank,
Its R22.
Your right that I dont know how much refrigerant is in there at the moment. Is there an easy way to find out how much? That way I can just put the gas bottle on the scales and charge the rest. If not, would it be feasable to release all the gas and that way I know there is nothing in there and then charge the specified amount?
what would happen if i put too much in?
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reclaim into an empty bottle...
then weigh that back into the system, stopping when you reach the correct weight. Adding gas from another bottle of 22 if you require more gas for the correct charge weight.
(doing this of after knowing you have fixed any leaks etc on the unit first of course)
not familliar with daikin splits personaly, but would think the charge would be around 4kg give or take, it sound be on the plaque on the outdoor unit, along with model and serial numbers, amp draws etc (also most possibly indoor head).
do you know the exact charge frank off the top of your head?
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Re: problem with split a/c
Hi Bones,
1.8Kg of R22. It says on the outdoor unit.
Can u tell me what the proceedure is for emptying all the gas into the bottle?
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Re: problem with split a/c
Frank
He says it's on R22
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Re: problem with split a/c
Quote:
Can u tell me what the proceedure is for emptying all the gas into the bottle?
do you have a fridge mate who would have a recovery unit? if he does, use this to suck the gas out of the system and into a recovery bottle. (perhaps he might do it for you if offer to quelch his thirst with beers hehe)
otherwise chill your recovery bottle, put it in a bucket with some ice or depending on the size put it in (there) your freezer for a little bit, as refrigerant will migrate to the coldest spot... thus hooking your guages to outdoor unit, purging to chilled recovery bottle will suck alot of gas out by itself.
also make sure you use a clean bottle and vaccuate it before recovering.
i take it your possibly not from nsw, otherwise have a fridge mate buying the 22 for you? if you are, dont get caught big $$$ fines.
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Re: problem with split a/c
Daikin did not make any split units on R22 with inverter drives except for the vrv stuff. If you do not know how to reclaim refrigerant - what are you doing working on the equipment??
I don't want to sound condesending but it is a skilled job and should be left to the experts - not only as we have trained for a number of years but it can lead to severe accidents. enough said.
If you wish to post the model number of the outdoor unit I will gladly post the correct charge weight. There is no short cut to knowing how much refrigerant is in the system. You must reclaim the charge and weigh it (specialist equipment required). You must then ensure that the system is leak free and recharge to the manufacturers stated charge. If the system does not then perform as it should do, you have to start looking for the cause of the problem. Just by charging the correct amount of gas does not mean that it will work correctly.
GET PROFFESIONAL ADVICE.
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Re: problem with split a/c
Quote:
Originally Posted by slothslag
Hi Bones,
1.8Kg of R22. It says on the outdoor unit.
Can u tell me what the proceedure is for emptying all the gas into the bottle?
Connect a half-full bottle to the thickest of the 2 tubes and start the compressor and turn the bottle then upside down.
As soon as you hear that the compressor stops and Amps are rising very fast - can take some time - then it's OK. Then all the gas is gone ;)
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Re: problem with split a/c
Quote:
Originally Posted by Peter_1
Connect a bottle to the thickest of the 2 tubes and start the compressor and turn the bottle upside down.
As soon as you hear that the compressor stops, then it's OK. ;)
I'll go along with that Peter, it is after all the best way for fools to carry on and when the motor does stop it can be confirmed that the compressor is full. :mad: :D
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Re: problem with split a/c
Quote:
Originally Posted by frank
Daikin did not make any split units on R22 with inverter drives except for the vrv stuff. If you do not know how to reclaim refrigerant - what are you doing working on the equipment??
GET PROFFESIONAL ADVICE.
This is the problem with a worldwide forum. What applies to one country doesn't to another. In Australia, Daikin inverter splits are predominately R22, although R410A units are now becoming available. These are standard domestic splits. I have 2 in my house.
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Re: problem with split a/c
Paul,
I have to agree with Frank. If you aren't totally 100% cetain leave it to a trained engineer (I don't want to sound condescending either, but it's so easy to make the problem a whole lot worse). We work almost exclusively on VRV systems and Hitachi VRF's. The Daikin VRV 2 is the 410A Inverter driven system.
The thing to do would be to reclaim the refrigerant into an appropriate vessel(you can't release the gas into the air) (liquid first if possible), and then get the remaining vapour out. Leak test using OFN- if you can leave it in overnight, and then once the leak is repaired, or the whole system is 100% pressure tight, pull a vacuum (to around 200 microns), and leave the system for a little while, making sure the vacuum holds (if the presure rises then stops, it's usually moisture in the system boiling off- so pull the vacuum down again until it holds). As the other guys have already said, check the manufacturers charge weight, and then WEIGH IN the correct charge. This way you can get the correct charge in. If you put in too much, then you can damage the compressor, as it will start to take in liquid slugs. The pressures will be high, and you still will not get the desired cooling, so it is essential that the corrct charge is weighed in. Hope this helps.
Regards
James
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Re: problem with split a/c
thank you all for help. much appreciated.
especially iceman007 - thanks for your info
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Re: problem with split a/c
hi guys,
if i fit gauges to the high pressure and low pressure sides. can i tell from that if it has correct charge, or at least near the correct charge or that im not going to ruin the compressor if ive put in too much? if so what values of pressure am i looking for and when?
Paul :confused:
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Re: problem with split a/c
Quote:
Originally Posted by slothslag
hi guys,
if i fit gauges to the high pressure and low pressure sides. can i tell from that if it has correct charge, or at least near the correct charge or that im not going to ruin the compressor if ive put in too much? if so what values of pressure am i looking for and when?
Paul :confused:
Sure, you can. You must charge till you see HP is going up.
Almost same procedure as emptying the system as you asked in a previous post.
You must connect your gauges and your gas cilinder. You charge your system until you see the HP rising until you have a difference of +/- 50 K with ambient temperature.
You measure aslo the AMP's of the compressor and as soon you reach max AMP stated on the compressor, then it's correct filled.
If needed, adjust safety tripper on the current safety switch.
Don't bother if suction is becoming wet or iced. That's normal.
Suction pressure should be +/- the same as the suction pressure which corresponds to the temperature of the room (for 40°F, you need a suction pressure of 120 psig with R22.
Let me know if it worked. :D :rolleyes:
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Re: problem with split a/c
i would hesitate to say that a frosting suction is 'okay' on a daikin split..to me it indicates (all else normal) it's overcharged..
although japanese condensers are oversized for europe so they will over condense and give a low suction -40 to 50 psig- they can ice during colder times if a 'split' is put into a comms room without hp control etc..
it's interesting that a lot of split a/c guys have absolutely no idea at what high pressure a split runs now a days..nor why it runs at 45 psi suction...
personally i feel the best way -aside from doing correctly- is to charge till it sweats at the suction flare nut -if it frosts i take a little out
bit like charging to the frostline on fridges etc
cheers
richard
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Re: problem with split a/c
hi paul,
a good operating split, depends alot on a good installation. some times, a lazy installer would bend a pipe by hand, almost stoping the gas flow. in such cases, you can charge it forever and it will not show you proper suction/discharge temps.
check by hand all the bends to eliminate this problem.
as peter said, check amps. on every split you will have a lable that show the working conditions, it is usualy different amps in cooling or heating modes, so make shure if what you measure is ok.
in most modern splits, condenser fan is controled be condensing temp.( on/off)
does this one have that control? is it working ok?
do not forget that in heating mode, condenser becomes evaporator and if the fan stops, suction temp will drop.
on a split that works in cooling mode in the winter or cold ambient you must install head presure control, these little devisces sense the condenser temp and control the fan speed. very useful in computer rooms for example.
go slow arround all the possible reasons for your problem.
I think that all the suggestions you got her, have to cover the problem.
please, let us know what was it.
good luck
chemi
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Re: problem with split a/c
Paul
You can connect gauges and charge to the correct level. The easiest way is to look at the label and weigh in the correct charge. If you cannot do this then you may need to charge by superheat, if it's a normal split with no inverter.
Connect the low and high side gauges to the ports and connect the service hose to the bottle. If its a non azeotrope YOU MUST TAKE THE REFRIGERANT FROM THE BOTTLE AS A LIQUID (if its R407c or R410a charge as a liquid - if there's only one port on the bottle you will have to turn it upside down to draw liquid). Only open the valve on the gauges approximately quarter of a turn to let the liquid flash off in the lines before the compressor draws it in. Take a temperature measurement on the suction pipe at the condenser and watch carefully the LP reading on the gauge. Charge a little at a time and let the system settle down each time rather than bomb charging it in. Take the temperature scale on the gauge and compare to the temperature reading on the suction pipe and charge slowly until the temperature of the pipe is approximately 5 to 8 degrees higher than the temperature that the needle on the compound gauge is pointing to. This means that the superheat is approx 5 to 8 degrees, and the compressor will not be drawing in liquid, but the evaporator will be performing as it should. In any event you should also feel the air off the condenser start to warm up as it rejects the inside heat. If you connect the HP gauge, once the system has settled, look at the needle and read off the temperature indicated for the gas in use. This temperature should typically be 20 degrees C (35 deg F) higher than the ambient temp- if the system is condensing too much over this than there could be a problem. Once you have done that, make sure you check that the compressors current draw is within the range shown on the plate.#
Most important of all, before you do any of that, make sure it's pressure tight and correctly evacuated.
Hope this helps out- any problems send me an e-mail.
Cheers
James
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Re: problem with split a/c
hi guys,
thanks for the info. The system IS an inverter but this is some data that i have got from it.
i put it in cooling on powerful mode. it was a mild day outside. about 25 deg C
rated current is 11A on cooling but it was sitting on about 8A fairly steady the whole time in powerful mode.
temp of suction pipe = 6.4 deg C
temp of liquid pipe = 14.8 deg C
suction pressure = 60 psig (corresponds to -4 deg C on gauge)
liquid pressure = 100 psig (corresponds to 12 deg C on gauge)
indoor unit air on = 22.6 deg C
air off = 6.4 deg C
outdoor unit air on = 25.4 deg C
air off = 31 deg C
everything was fairly steady the whole time. does this sound like everything is okay? I am alittle concerned about the liquid line pressure. is it too low?
cheers
Paul
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Re: problem with split a/c
you are probably not reading discharge pressure -if their is a connector on the smaller 3/8 pipe service valve then you were reading the 'pre expansion'pressure -if so 100 is about right..
cheers
richard
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Re: problem with split a/c
what is pre expansion pressure? i had the high pressure gauge on the liquid line service port it is a 3/8 " pipe
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Re: problem with split a/c
Quote:
Originally Posted by slothslag
hi guys,
temp of suction pipe = 6.4 deg C
temp of liquid pipe = 14.8 deg C
suction pressure = 60 psig (corresponds to -4 deg C on gauge)
liquid pressure = 100 psig (corresponds to 12 deg C on gauge)
indoor unit air on = 22.6 deg C
air off = 6.4 deg C
outdoor unit air on = 25.4 deg C
air off = 31 deg C
everything was fairly steady the whole time. does this sound like everything is okay? I am alittle concerned about the liquid line pressure. is it too low?
It's difficult to charge an inverter system by measuring amps, as you won't be able to measure the compressor loading accurately. If it's a Daikin unit then i think you must measure in the correct charge. It's difficult to be able to fault find from the other side of the world, but I think that the LP is a little low if the liquid is evaporating at -4 degrees (make sure the indoor coil doesn't ice up). I would be looking for a temp just over zero. The outside air is around 25 degrees, then the HP should show the system to be condensing at around 45 degrees, and you should get sub cooling of between 4 and 7 degees. If you are on R22 the values I would look for (in theory) would be, a suction pressure of around 60 psi-gives evaporation temp of around 2 degrees, and a suction line temp of between 7 and 10 degrees (5-8 degrees superheat), HP of around 240 psi (at 100 psi it will not condense as the condensing temp MUST be higher than ambient) 240 psi shows a condensing temp of about 45 degrees, and the sub cooling should be ideally 4-7 degrees, gives a liquid temp out of the condenser of between 38 and 41 degrees.
What you have is a slightly raised superheat and not correct sub cooling (could be lack of charge), but the suction pressure seems OK (if it's R22), but from what you have said, are you on R407C?
This is only theoretical summary, and in practice could be different, let me know how you get on
James
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Re: problem with split a/c
the expansion device on most splits is in the condensing unit.
therefore you are reading a liq/gas pressure after that device
hence you are not reading discharge pressure
in order to do this some -but not all- have another schraeder in the discharge pipe out of the compressor but before the 4 way valve....
look for a fitting in amoungst the pipework above the compressor...
if you manage to fit your gauges on this one you would read a much higher pressure 220 -270 psig
cheers
richard
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Re: problem with split a/c
no its r22.
now i am confused. am i measureing the condenser pressure or "pre evaporating pressure" on the service port of the small pipe?
where is the tev? is it in the indoor unit or the outdoor?
and if what you say is right about 45 deg C condenser temp why is the small pipe about 15 deg C and not 45 deg C?
thanks :confused:
Paul
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Re: problem with split a/c
Quote:
Originally Posted by rbartlett
i would hesitate to say that a frosting suction is 'okay' on a daikin split..to me it indicates (all else normal) it's overcharged..
cheers
richard
Haven't seen the :D :rolleyes:
Sorry, but I think Paul better calls an aircotech because his questions are so elementary that I think he never worked on an airco before.
Same for
Quote:
no its r22.
now i am confused. am i measureing the condenser pressure or "pre evaporating pressure" on the service port of the small pipe?
where is the tev? is it in the indoor unit or the outdoor?
and if what you say is right about 45 deg C condenser temp why is the small pipe about 15 deg C and not 45 deg C?
TEV?
Pre-evaporating pressure? 100 x :confused:
Perhaps the last discovered 'inverted pre-subcooling' of the liquid at ambients of 20°C?
You see what I mean.
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Re: problem with split a/c
if you read my post above it answers all your questions..
cheers
richard
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Re: problem with split a/c
okay thanks richard ill check it out :)
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Re: problem with split a/c
richard ,
there is no port where i can fit a gauge between the compressor and the reversing valve. is there any way of checking the condensing pressure now?
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Re: problem with split a/c
peter 1 ,
mate i am doing all this to learn. i will not "call the pro" because oneday i will be the pro, how do i get there?? ... by asking elementary questions :mad:
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Re: problem with split a/c
any chance of getting a digital camera and posting a couple of pics?
and a model/serial number..
cheers
richard
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Re: problem with split a/c
Wasn't the filter completely clogged whereby in cooling mode there was no load on th evaporator and in heating mode it became very hot, so no sufficient cooling of then the condenser?
Fan was running but Frank already asked this?
Just a completely clogged filter. Have a look or run without filter for some time or open the simply the suction grille and let it run. Same symptoms?
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Re: problem with split a/c
hi marc,
I would like to add that when the filter is clogged with dirt for some time, the dirt is getting inside pass the coil and lands on the wings of the tangential fan.
the result is almost no air coming out because the the curve of the wing is now straight.
chemi