how to calculate the additional refrigerant to be charged? help me!

[khongminhhason]

hi everyone,
we have just installed the VRV III and now we testing system with high pressure
i 've read technical specification of RXYQ18, the refrigerant charge is 11,7kg
i don't know when should i charge the additional refrigerant?
and how to calculate the additional refrigerant?
thanks you in advance

[The Viking]

In the outdoor unit there is an clear plastic bag that got the install manual and a couple of "silver" grey stickers in it amongst other things...

Follow the procedure in the install manual to assist you as to when and how to add your additional charge.

One of the stickers will tell you how to calculate the charge...

:cool:

(RTFM)

[jdunc2301]

Daikin...measure the liquid line length

Liquid line length x charge stated in manual (eg 200g)

See manual tho and don't just estimate it! Measure correctly and allow for bends etc

[The Viking]

Daikin...measure the liquid line length

Liquid line length x charge stated in manual (eg 200g)

See manual tho and don't just estimate it! Measure correctly and allow for bends etc


Uhum....
VRV, so slightly more complex but you are right the same basic principle applies.

:cool:

[jdunc2301]

Only going by the last phone call to Daikin, mind you that was on a ancient system

J

[install monkey]

goes to show daikins technical advice should go in 1 ear and straight out the other:D

when installing you should have a daikin approved schematic piping diagram with refnet sizes,bs box sizes- every pipe size is on this drawing- when installing the actual pipe lengths can be added to this as when calculating the additional you need the total length of each liquid line size -so total lenght of 3/8,total 1/2 etc then add it to the daikin formulae- add 1kg for the additional and add outdoor factory charge too. simples
ps vrv3 will have an auto charge function- but this is slow-you need to add at least 80% of the additional charge prior to initiating this

Only going by the last phone call to Daikin, mind you that was on a ancient system

J

[jdunc2301]

goes to show daikins technical advice should go in 1 ear and straight out the other:D

You have spent way too long installing daikin my friend ;)

[install monkey]

dont do daikins now- dont want to end up like vrv3,1 clever monkey !!
:cool:

You have spent way too long installing daikin my friend ;)

[cold.man]

don't do like this guy i heard about who did an install of a MHI VRF system followed the pipe schematic approved by MHI well for the first few days.
for one didnt purge with nitro, two didnt keep to the schematic, three when he realise he had to know the size and length of each induvidual liquid line after having a chat with this guy in the suppliers. The guy went back to site as the outdoor units had not been piped up due to no slabs laid yet and found the plaster board ceilings had gone in.
now this guy had fit splits and multi splts etc never done VRF systems, got offered this install and thought he would have a dabble.

[install monkey]

must have been a fridgie-charge to the sight glass!! haha.
1st ever daikin vrv i went to repair- r22-about 16yr ago -each had sight glasses fitted on liq lines and on a 15storey bldg 3 systems , each did a server room on each floor- 5 server rooms per system- they prob fitted oil traps on it too- turns out it lost gas on its acess valve caps

[soleowner]

For US Models of VRV III, the outdoor unit is only charged for the ODU itself. The refrigerant charge calculation is measured from the ODU and every inch of the refrigerant circuit.

Do you have a VRV Express file? If not, this is a good starting point.

Email me and I will send you a Excel spreadsheet for Additional Charge Calculation and a PDF slide presentation on commissioning.

[khongminhhason]

thanks you

[khongminhhason]

Hi soleowner,
i don't have that file, i would be happy when receive your file via this email: khongminhhason1@gmail.com
thank you very much.