Daikin VRV111 OFN contamination

[Thermatech]

I think I have been caught in the old VRV OFN contamination trap.Its a 3 pipe system.

After vac & trim charge the system will not complete test run but stops on E3 high pressure.The high side gradually gets up to about 39 bar before stop.

My mistake it would seem was to evacuate before power on to outdoor unit & did not select evacuation mode to open up all valves so suspect some ofn may have been trapped between BS boxes & indoor units.
But it must be a very small amount of ofn because the system refrigerant standing pressure is 9.5 to 10.5 bar depending on ambient temperature.
Next step to recover all refrigerant evacuate & recharge again.

Can our resident Daikin experts provide a definative guide to pressure test, evacuation & trim charge procedure for the latest VRV 111 3 pipe systems.

[frank]

The indoor units are sent from the factory with the EEV's in the open position.

You must complete all pressure testing and evacuation procedures before applying power to the indoor units because once power is applied they pulse to the 100% closed position.

More than likely, your pressure test has resulted in OFN passing into the outdoor unit via the service valves on this occasion. This is why Daikin recommend that the indoor pipework is pressure tested PRIOR to connecting to the outdoor unit.

[The Viking]

???
I might be wrong here, you all knows it happened in the past.
But, by the sound of it you have just commissioned a new system.
If this is the case (at least on VRVII) the BS boxes should been delivered with the valves open and you shouldn't need power to do the P-test/vacuum bit....

Any chance of OFN passing the valves during the p-test?

But I haven't been lucky enough to get my hands dirty on the VRVIII yet:(

No doubt a more Daikin orientated user will be around soon to give us a definite answer.

[Thermatech]

Yep just commissioning new system.

Engineers who did the install have all learnt the hard way & know to tighten up the service valves before pressure test. I had to extend the allan key with large adjustable spanner to undo the service valve they were done so tight.

My thinking is that the electricians may have turned on the ring main to the indoor units & BS boxes at some stage so although we expected the indoor unit LEV valves to be open actually they may have been shut.
Because we were still waiting for the electicians to install 3ph power to outdoor unit I went to evacuation stage. But was some small volume of ofn trapped between BS box & indoor unit ?

At this stage I think Ive fallen into the VRV ofn trap & should have walked away from the site untill power finaly connected to outdoor unit.
But in this case commissioning site visit already delayed twice due to electrician failure to provide 3ph power as prommised. Site now subject to late completion penalty clause.

[transit 1]

I think I have been caught in the old VRV OFN contamination trap.Its a 3 pipe system.

After vac & trim charge the system will not complete test run but stops on E3 high pressure.The high side gradually gets up to about 39 bar before stop.

My mistake it would seem was to evacuate before power on to outdoor unit & did not select evacuation mode to open up all valves so suspect some ofn may have been trapped between BS boxes & indoor units.
But it must be a very small amount of ofn because the system refrigerant standing pressure is 9.5 to 10.5 bar depending on ambient temperature.
Next step to recover all refrigerant evacuate & recharge again.

Can our resident Daikin experts provide a definative guide to pressure test, evacuation & trim charge procedure for the latest VRV 111 3 pipe systems.
hi there just remember when u go into recovery mode do not kill power on out door unit just indoors on vrv 3 . vrv2 u do both indoors and outdoor . ps if there was no power on indoors when vaced there should have been no probs .

[puddleboy3]

Can our resident Daikin experts provide a definative guide to pressure test, evacuation & trim charge procedure for the latest VRV 111 3 pipe systems.

I never claim to be an expert but my advice to you would be dependant on what stage you are at!

Installation stage : Always best to pressure test/vac and add trim charge with the power never having been switched on to the indoors. I always disconnect the F1 F2 wire from the outdoor and get the power on to the condenser as soon as I get to site and get those crankcase heaters warmed up!

Problem stage: The power has been on to the indoor side of your system before pressure testing etc. This is one for Obi Wan but I know that on the VRV II even if power had been on to your system there was always a flow path through your BS box the problem was that the indoor exp valve motored to the closed positon when the power was switched on. So we always got around this problem by pressure testing/vac all three lines plus oil equalising line on heat recovery!

I cant imagine that the VRV III BS box completey shuts down with no flow path! But as per usual I've been wrong before. Plus I would advise against putting mode 2 setting 21 in to the outdoor unit to force all the system valves open if the outdoor service valves are still in the closed positon as this opens all the valves on the outdoor as well as the indoor possibly causing liquid refrigerant to make its way in to the suction lines, compressor etc!

[Thermatech]

In this case ring main to indoor units & BS boxes was complete weeks ago & ofn added to complete system weeks before that. No one can be sure that 240v has not at any stage been turned on to the units & then switched back off again which would have closed the indoor valves.
Because the spurs were all off when I arrived at site to carry out commissioning I made the classic mistake to assume the valves would be open.
I will pay for that assumption by spending a day carrying out evacuation & recharge with new refrigerant.

Does any one have a proven procedure of pressure test & evacuation to ensure that no ofn can be left in the system?

[philjd26]

hi
i know how to get in to setting mode 2 on the outdoor pdb, however in my service manual it does say any thing about setting 21...can anyone help

[Reefer1]

Firstly ensure LED H2P is on or off not flashing.

Enter into setting mode 2 by holding mode button until H1P LED comes on.

Press the set button 21 times until LED's HP1,3,5 and 7 are on.

Press return button

Led HP7 will be flashing

Press set button once

Led HP6 will be flashing

Press return button twice

Expansion valves and some of the solenoid valves will now be open and evacuation can be carried out.

[sinewave]

Two things have struck me reading this post!


1) If Daikin recommend pressure testing without connecting up to the Condenser (presumably because they don't trust their valves) then the final connections don't get pressure tested do they so one assumes that all you can do on final commissioning is use leak spray and a sniffer?


2) Being a qualified Electrician myself I find it hard to believe that the Spark would have run round switching on all your DP Isolators feeding the indoor units, there would be no need for him to do this for any initial testing purposes and assuming they are buried above the ceiling grid then accidental switching by others is unlikely.

The Spark will have needed all DP switches in the off position anyway to carry out his dead tests and live testing and any switches left on by your guys would have shown up at the 'Meggering' stage, and if he wapped it with 500V straight off without first using the 250V setting then your PCB board(s) in the indoor unit(s)would probably have got fried to boot.



Just some thoughts that's all! :D

[Reefer1]

Daikin do require all piping to be completed before pressure testing and evacuation is carried out. It is extremely seldom for there to be any problems with the valves as the valves do not have to be touched until pressure testing, evacuation and additional refrigerant charge have been carried out thus meaning possibilty of leakage etc.. is greatly decreased.

Sinewave you are a one of very few sparkies in my experience who would go to the trouble of doing things properly as you have described.

In my experience sparkies will wait for commisioning to see if there wiring works ok. Most seem genuinley relieved when I tell them there wiring is working correctly...

Sign of the times I guess!

[Thermatech]

An up date for any who were looking at this thread.

Daikin Technical help desk were absolutely sure that the system must be ofn contaminated.
I was sure it was not ofn contaminated because the standing pressure was spot on.
But we got the installation enginners back to remove the refrigerant anyway. While the recovery rig was doing its stuff we looked very closely at the pipe connections at the outdoor units ( 2 outdoor units connected together )
Turns out the install engineer made incorect pipe connection for the equalising line.
VRV11 had oil equalising line & new VRV111 has high pressure equalising line.
Before the engineer changed the pipe connections we rang Daikin technical help desk to confirm & make absolutely sure of the corect pipe connections.
Guess what,,,, they did not know & had to ring back later to confirm !
Sure enough the refrigerant charge was correct & standing pressure in the recovery cylinder spot on as it was in the system. No ofn contamination.
So after changing the pipe connections, vac & recharge with the same refrigerant then the system ran ok without fault.

Because Daikin technical were so sure that the problem was ofn contamination it makes one wonder if that is the standard answer they give out to anyone who has a high pressure problem at commissioning.
This also make one suspect that they still after many many years have problems with high pressure ofn leaking back into the outdoor unit when pipes connected & carrying out strength test.

This week I had ofn contamination on Hitachi VRF system with high pressure fault. In this instance the standing pressure was 27 bar.
Installation engineers recovery rig blown fuse twice trying to get the refrigerant out.
Vac & recharge with new refrigerant & system ran perfect.

This is why some manufactures advise pressure test system before making final connection to outdoor unit. But then the last joint to the outdoor unit has not been strenght tested. So most install engineers continue to make pipe connections to outdoor unit & then pressure test & hope the service valves hold.
From time to time the valves dont hold & ofn leakes back into the outdoor unit.

[Dan1947]

mode 2 setting 21 refrigerant recovery and evacuation mode

[El Padre]

I have always thought that it would be preferable for all condensing units to be delivered/sold with no refrigerant in them, just a holding charge of OFN just like chillers and close control units.

Cheers

[frank]

I have always thought that it would be preferable for all condensing units to be delivered/sold with no refrigerant in them, just a holding charge of OFN just like chillers and close control units.

Cheers
The Plumbers wouldn't be able to fit them then. ;)

[El Padre]

I never claim to be an expert but my advice to you would be dependant on what stage you are at!

Installation stage : Always best to pressure test/vac and add trim charge with the power never having been switched on to the indoors. I always disconnect the F1 F2 wire from the outdoor and get the power on to the condenser as soon as I get to site and get those crankcase heaters warmed up!

Problem stage: The power has been on to the indoor side of your system before pressure testing etc. This is one for Obi Wan but I know that on the VRV II even if power had been on to your system there was always a flow path through your BS box the problem was that the indoor exp valve motored to the closed positon when the power was switched on. So we always got around this problem by pressure testing/vac all three lines plus oil equalising line on heat recovery!

I cant imagine that the VRV III BS box completey shuts down with no flow path! But as per usual I've been wrong before. Plus I would advise against putting mode 2 setting 21 in to the outdoor unit to force all the system valves open if the outdoor service valves are still in the closed positon as this opens all the valves on the outdoor as well as the indoor possibly causing liquid refrigerant to make its way in to the suction lines, compressor etc!

Good point, does anyone know which valves are opened on the outdoor unit in recovery/evacuation mode, just thinking if its possible to disconnect the outdoor valves from the board prior to putting it in to that mode, in cases like this where you only want the indoor valves to open.

There is no flow path on VRV III, I will try to attach the slide from the course notes. Sorry its 1.18MB

Cheers

[brunstar]

Good point, does anyone know which valves are opened on the outdoor unit in recovery/evacuation mode, just thinking if its possible to disconnect the outdoor valves from the board prior to putting it in to that mode, in cases like this where you only want the indoor valves to open.

There is no flow path on VRV III, I will try to attach the slide from the course notes. Sorry its 1.18MB

Cheers

When putting the system into refrigerant recovery mode all of the expansion valves will open within the entire system.
It is best to leave them all connected anyway.
In regards to the liquid within the outdoor unit this will be boiled of when the crank case heater are energised.
When the system runs in test you will find it will run in colling first to remove all of the liquid from the outdoor unit and get it into the pipework for this reason.
When turning the system on for the first time, be careful as you will find that the crank case heaters in some systems will not come on until F1 and F2 are connected and the system is communicating.

If you check 240volts to the crank case heater not there this will be because there is no communication to indoors.
If you need the crank case heater to be on before the F1 and F2 connected you may have to apply the voltage from another set of terminals ont he outdoor unit.