Hi
We purchased a used 3 group La Marzocco Linea they came and installed it but we had to have them come right back and put our old 2 group back in as it was not working. After talking with the tech he was unsure of what could be causing the problem, he was is leaving for vacation for a week and said he would try and figure it out when he came back. So I thought id see if anyone on here knew.

Its a 1998 Linea AV 3 group
The program key was missing so he just twisted the 2 wires together from the back of the key so you could go into program mode.
We went and programed all the buttons for 2.5 oz shots. After a few minutes you would go back and press the button and you might get half a 2 oz shot or a 1.5 oz shot. It would vary between the heads and all 3 group heads were doing this. He said he had never came across this problem.
Anyone else had this problem ?
Thanks