Daikin VRV systems oil separator

[Taaz1275]

Hi, would someone who is more familiar with these system kindly explain the oil separator makeup,
does it have the float valve in them like all oil separators in refrigeration systems that I know of.
I have seen that in Daikin VRV (their first edition sets) ..have this oil return line (capillary # 10) linking the oil separator to the suction line before the inveter compressor. Also their is a pencil drier and a sight glass incorporated between the oil return line which I believe filters the oil as it returns to the compressor.
The issue is, inverter compressor has been replaced 3 times in a row of 3 years, which makes that an approximate of 1 inveter compressor per year. History of the system as being told is that it has always had the issue of oil failing to return to the compressor hence the burnt out. Apart from my original question regarding the float valve, if anyone is willing to share some light as well on the oil test acidity levels and correct capillary sizes used on the oil return line .. it would really be great and resourceful. ..thanks guys, hoping to hear from the Daikin experts out there.

[install monkey]

when you change a compressor your meant to vac out the oil out the other and replenish with fresh, if youve done 3 compressors on the same system then driers may be getting clogged

[frank]

What series of VRV is it?

[Taaz1275]

History on unit as told, for every inverter compressor changes that were made within the 3 years prior, oil was flushed out of the oil separator. Capillary oil return line and oil filter replaced. New fresh oil filled into oil separator, but no oil change made on the other (fixed speed) compressor. Could i further ask if should the other adjourning outdoor unit connected to the same line up/ set up (group) compressor or system oil be replenished with new oil as well?...what about my original question on the oil separator float valve, does it have one? Or the design of this oil separator is just a vessel with an open line (thru the link of the oil return capillary line) back to the suction of the inverter compressor...whereby it does not have a high side float valve?

[Taaz1275]

RNY10KY1 ...3pipe system

[Taaz1275]

RXY 10K..3 pipe system. ..3 outdoor units operating 10 indoor units ...indoor is just one stairs below outdoor units.

[Taaz1275]

I was just going thru the forum and was reading thru some interesting oil probs faced within supermarkets vs vrv's. Someone did mention the periods of low loads and the need to increase head pressures to create the condition to enable the oil separation to in fact take place in the oil separator(R404a)...someone also mentioned the designed operation of the Daikin vrv in attaining the oil reclaim process when running after ~ 8 hrs under low loads, if im correct, opening up eev and turning off the indoor fans and running in full capacity for a certain preset time to recover back the oil....good resourceful reading ...im still lost with the question, does the oil separator have a float valve inside, especially with vrv Daikin model makeup?

[qcfish]

When they replaced compressors and flushed out oil separator did they measure oil volume? Is it possible that there is excess oil in the system? is the oil in the system black or dirty, which will need cleaning? Did the pull a long good vacuum for a long time while Mode 2 was in the recover/evacuation setup? Personally I would flush out all lines, new driers, etc when I replace a compressor on these units. Inverter comps on these setups take the majority of the work. Daikin has good head pressure and oil return that work well in low load and normal conditions.

Do you ave access to a Daikin service checker that can log info for 24 hrs or even for an hour? Oil is not returning, so somebody has verified low oil level on bad comp? Load it up for a long time if possible and verify max HZ is close, then check pressures, superheat, subcooler EXV,discharge line temp, etc if you don't have a SC. Daikin has free tech support too. good luck

[frank]

Check the lengths of the indoor pipework to make sure that out does not exceed 40 metres from the first branch joint to the last cassette.

If the pipework exceeds 40 m then you will suffer from poor oil return and premature loss of compressors