Happened to me last weekend. Was descending down the shot line alone and I could hear bubbles and also see them reflected in the Petrel. Stopped to work out what was going on. Rolling side to side and going vertical didn’t reveal where the leak was coming from, but it appeared to be behind me.
Set the Nerd to display the large numbers and waited for a minute to see whether it was the oxygen or diluent. Also very aware of monitoring the unit — water in the loop, etc. Basically neither and the loop was breathing fine.
Must be bailouts— two tins, lean left, rich right. Turned off the RH decompression gas, no change. Turned off the LH bailout and it stopped. So could bail out but must turn on gas. Proceeded down the shot to get another diver to look at where the gas was leaking from.
Then realised it was the BOV hose connector which had worked itself loose. Bubbles running up the loop cover and out the back of the unit. Tightened up the hose 9/16 connector two whole turns and turned the gas back on. Fixed.
Lovely rest of dive. The digital readout of gas pressures from the Nerd was a very useful tool in analysing the problem.
Have used a spanner to really tighten up the BOV LP hose and note the nut position as part of the climb-into-the-unit check.
