Daikin VRV-S refrigerant leak

[mchild]

This is a Daikin VRV-S II installed in 2008, model number RXYMQ48MVJU connected to four indoor ducted units FXSQ-M. This is the first problem with this system since installation.

Unit tripped out on F3 - High discharge temp. After checking t-misters and such found the unit low on gas (total charge is 15.3Lbs found loss of 2.9Lbs). Inspected all flair connections and refnet branches to see if there was evidence of trace oil from a leak, but nothing showed. Used a refrigerant sniffer around outdoor unit coil and piping and all indoor unit coils. Sniffer did not detect any leaking refrigerant.

I have done a search on the forum for likely refrigerant leak points on this equipment. While I have found lots of information on other Daikin models that have leak problems, I have not found much on this equipment.

I am hoping someone with experience on this model of equipment can suggest other likely areas that may leak.

Thank you.

[still learning]

Did you pressure test with ofn , when all the gas was reclaimed from the system?
I like to separate the out door side of the system from the indoor.
Put 15 bar into the outdoor on a gauge and hose, shut the service ports and then put gauge on indoor side. And take to 20 bar. And wait 24 hours.
Yes service ports. Can leak back , but I've found that rare.
You may find. One side is. Down .
It would seem to be a small leak as you have not lost much gas , over the six years.
All so you could try a bubble test on the flares, may not show at first glance.
But wait, and see if you get that tiny blip.
Some refrigerant can hide under the oil in the compressor
Good luck.

[mchild]

Did you pressure test with ofn , when all the gas was reclaimed from the system?
I like to separate the out door side of the system from the indoor.
Put 15 bar into the outdoor on a gauge and hose, shut the service ports and then put gauge on indoor side. And take to 20 bar. And wait 24 hours.
Yes service ports. Can leak back , but I've found that rare.
You may find. One side is. Down .
It would seem to be a small leak as you have not lost much gas , over the six years.
All so you could try a bubble test on the flares, may not show at first glance.
But wait, and see if you get that tiny blip.
Some refrigerant can hide under the oil in the compressor
Good luck.

Thank you still learning for your thoughts. No, we have not yet isolated the indoor from the outdoor and pressurized them individually. We'll start with bubbles on the flairs.

[hyperion]

If the system is still operational, you could try adding a small quantity of leak detection dye.
Let the system run for a period of time, maybe an hour or so and then use the UV lamp to check for leaks.
This may help you to speed up locating the leak.
If it has only lost a small quantity over a relatively long period of time it can sometimes be difficult to find the leak, or it could be that the leak has only recently occurred and is losing refrigerant at a rate that can be detected.

[mchild]

If the system is still operational, you could try adding a small quantity of leak detection dye.
Let the system run for a period of time, maybe an hour or so and then use the UV lamp to check for leaks.
This may help you to speed up locating the leak.
If it has only lost a small quantity over a relatively long period of time it can sometimes be difficult to find the leak, or it could be that the leak has only recently occurred and is losing refrigerant at a rate that can be detected.

We have been operating under the assumption that the leak is recent. Prefer not to use UV dye if possible and the reason we were hoping to find out the most likely places for a leak to occur on this particular equipment. Thanks for your comments.

[Brian_UK]

Check also where pipework may be rubbing against hard supports etc.

[still learning]

I had to look at a google image of a vrv s.
If it is. A twin fan looking like a split outdoor unit, I would look behind the compressor and up and down the coil , quite hard to see,dakin had a bit of a problem. With outdoor coils at one point.
Sometimes you can run your finger thru one of the drain holes in the bottom pan of The outdoor and feel oil mist residue.

[mchild]

Check also where pipework may be rubbing against hard supports etc.

Thanks Brian. When I did the site search I found and read about the RZQ models and the consistent problem with pipe work rubbing on the frame on the outdoor unit. Is this the same issue you are suggesting we look for?

[mchild]

I had to look at a google image of a vrv s.
If it is. A twin fan looking like a split outdoor unit, I would look behind the compressor and up and down the coil , quite hard to see,dakin had a bit of a problem. With outdoor coils at one point.
Sometimes you can run your finger thru one of the drain holes in the bottom pan of The outdoor and feel oil mist residue.

I think this is same issue Brian suggested - no? Does this require coil replacement or is it typically repairable?

[Brian_UK]

I don't know of coil problems with VRV's but I have had pipework leaks due to expansion and contraction rubbing pipes against heard corners, pipe trays etc.

[mchild]

I don't know of coil problems with VRV's but I have had pipework leaks due to expansion and contraction rubbing pipes against heard corners, pipe trays etc.

Got it - thanks.

[Asbolute]

This is a Daikin VRV-S II installed in 2008, model number RXYMQ48MVJU connected to four indoor ducted units FXSQ-M. This is the first problem with this system since installation.

Unit tripped out on F3 - High discharge temp. After checking t-misters and such found the unit low on gas (total charge is 15.3Lbs found loss of 2.9Lbs). Inspected all flair connections and refnet branches to see if there was evidence of trace oil from a leak, but nothing showed. Used a refrigerant sniffer around outdoor unit coil and piping and all indoor unit coils. Sniffer did not detect any leaking refrigerant.

I have done a search on the forum for likely refrigerant leak points on this equipment. While I have found lots of information on other Daikin models that have leak problems, I have not found much on this equipment.

I am hoping someone with experience on this model of equipment can suggest other likely areas that may leak.

Thank you.

I'd be surprised if you'd get F3 high discharge with a loss of 1kg from 7kg of gas. Are you sure there is not a refrigerant flow issue?

[mchild]

I'd be surprised if you'd get F3 high discharge with a loss of 1kg from 7kg of gas. Are you sure there is not a refrigerant flow issue?

No, not sure there isn't a flow issue. Since low gas can cause high discharge temp, when we found it low on gas we assumed that was the reason for the F3 code. At this point the F3 code has only occurred that one time and the unit is operating continuously after correcting the charge level. We will be undertaking the leak search in the next few days and once that has been corrected then we will see if there are any other operating issues. Thanks for the heads up on that.

[still learning]

I see what Brian means by hard supports.
and the corner of the coil behind the compressor is always worth a look , as there have been. Failures in the past, and yes the whole coil was replaced, on r z q models.
We only ever had four of your type of unit on one site and have only replaced a couple of fans And some boards I think .

[mchild]

I see what Brian means by hard supports.
and the corner of the coil behind the compressor is always worth a look , as there have been. Failures in the past, and yes the whole coil was replaced, on r z q models.
We only ever had four of your type of unit on one site and have only replaced a couple of fans And some boards I think .

Well, it is good to hear that overall the equipment is fairly well built. Just have to now locate that leak.

[Tayters]

On older VRV's (talking 10yrs, R407C) have seen the expansions valves leaking on indoor and outdoor units. If the leak detector goes off inside the unit, assuming you can get in there well enough then unscrew the head then you can see bubbles with leak spray. Outdoor EEV's bit simpler to check.

Not sure how this applies to newer models but thought worth a mention.

Cheers,
Andy.

[mchild]

On older VRV's (talking 10yrs, R407C) have seen the expansions valves leaking on indoor and outdoor units. If the leak detector goes off inside the unit, assuming you can get in there well enough then unscrew the head then you can see bubbles with leak spray. Outdoor EEV's bit simpler to check.

Not sure how this applies to newer models but thought worth a mention.

Cheers,
Andy.

Thanks Andy - I'll keep that in mind.