Water in pipes!

[Makeit go Right]

An engineer removed a condenser for repairs and sealed off the 3x circuits on a Daikin Multi-system.

Came back a week later to reinstall condenser with new parts and found that some plank had removed the taped up/plastic sheet covering over each of the circuit pipes. Open ends! Not just that: water in the first 6 inches of each pipe!
He poured out an eggcup-full from each one.

But the condenser was safe.

The plan is to: a) blast the circuits with nitrogen to purge out as best he can any water or moisture in the pipe runs to the room units, b) connect up the condenser, with a drier on each circuit, c) pressure test and d) vac vac vac until there is no sign of moisture in the system (ie Tor gauge).

That sound adequate?

[nike123]

I would separately make vacuum drying on each circuit before connecting condensers and put driers only after vacuum drying to 300 microns (and holding to 700 microns isolated from vacuum pump for more than 24 hours) each one. Than make pressure test and final vacuum drying as nothing has happened. Then regularly check driers for temperature drop across them, because oil residue in open pipes has probably absorbed lot of moisture, and only way to dehydrate oil is by changing driers.

[Brian_UK]

It has to be said that sealing pipes with plastic is not the way to go.

I would be wary of 'blasting' the pipes as it might push something further into the system. Perhaps a slow bleed to clear the air and follow Nike's suggestion.

[lomb]

Would there not be dirt in the pipes also? Possibly insects etc. Blasting is probably a good idea. Couldnt do any harm might also blow any water out. Maybe cut off a few meters of pipe and rebraze?

[lowcool]

cutting off a few metres of pipe will not remove contamination of oil in the rest of the pipework.the oil needs to be removed and as far as i know the only way of doing this is by flushing.

[Fri3Oil System]

the oil must be changed, otherwise, you will have an acidity problem in the midterm.
We have developed a special procedure/method to clean out water from AC plants.
check this video:
http://www.fri3oilsystem.com/ingles/video/video.html

[Makeit go Right]

Yes, the engineer should have brazed off the pipe ends – he realises that now, of course.

As for the remedy, a full cleanout/flush would be the best result, probably, but I cannot see this customer being willing to pay a large repair invoice (regardless of his accidental sabotage).

I think we will trim back the tails as much as we can (maybe 10-12 inches could come off), which is where the water collected. And, being at the bottom of these circuits, the nearby oil would have been somewhat gravitating down to that low point too (a bit). But a trim can only assist things. Then some nitrogen (maybe slow maybe blasting) to help dry things out, at least, and then Nike’s plan, with triple-vac until we get a good result.

Review things after running for a few days, ie check the driers in case they need a change, check oil acidity.

[SteveCass]

I might be wrong, but isnt the expansion device in the condensor and won't fitting the driers in the pipework outside the condensor effect cooling performance? Or will this be negligable?

[lowcool]

there are no residue solvent cleaners on the market that are reasonably cheap and effective,two flushes the jobs done,no further drier changes,oil tests etc.you can walk away with complete confidence with the repair.