Refrigerant leaks and detection dye

[cadwaladr]

I had a refrigerant leak on a medium sized walk in cold store which was on 404a the room was full of ice cream etc so not much time to recover and nitro test went all round with the electronic 100% certain the leak was not from service access points,picked up something on the evaporator,so added dye to the system now there is no further leakage question is can the dye plug a slight leak?

[chemi-cool]

No, it can not.
The amount of dye depends on the system size.
When the unit is running and evaporating pressure is low, it will be hard to find it.

Small leaks are usualy on the low side of the system. 404 does not carry oil well in low gas velocity, making it hrder to find any oil residue on the soldered points.

[cadwaladr]

I thought as much,true about the oil (leak detector agent that seals leak?),my next visit will be to have the room emptied and carry out a nitrogen pressure test

[chemi-cool]

Check this one out:
http://www.dayan-rs.com/_Uploads/dbsAttachedFiles/9111.pdf