Brera aircon mystery - detectives wanted
I have a mystery fault with the aircon which Iím hoping someone may be able to help with.
The system works for a few weeks and then stops due to low pressure, so the gas is presumably getting out somewhere. What is odd though is that it has been pressure tested numerous times and always holds the pressure (proper nitrogen test, not just holding a vacuum). Today it was nitrogen tested at very high pressure and was rock solid for 30 minutes. No sign of any leak, no hissing, nothing. Itís also been gassed up a number of times, with dye added, but they spent two hours on it today and could not find any trace of a mark from the dye.
So the question is can anybody think of a potential leak which ticks these boxes: (a) small enough to hold very considerable pressure for 30 minutes, and (b) sufficiently hidden away that the stain the escaping dye should be leaving cannot be seen?
Could it be the case that the leak is so small that somehow the gas can get out but the dye canít? Can that even be a thing? The only other thing I thought is that clearly the pressure test is done with the system not running, so might it be something in a moving part which is a causing the leak. Problem with that though is the only moving part is the compressor, and thereís no sign of dye anywhere near it, which presumably rules that out.
The garage and me are completely at a loss on this one. Itís like someone is stealing the gas when Iím not looking. Itís doing my head in and spending £60 every few weeks all summer to recharge it really isnít a sensible solution so any suggestions gratefully received. Help!