Hi Neil, yes F7 is a flow meter failure. I work on these all day and you find a machine can have 2 to 3 faults especially if water has got into the base.To access the air break with the flow meter in it,take off the left hand side panel and there it is.The flow meter is the electronics with the plug on it with two blue wires.You cannot buy the flow meter but if you get the air break it is all there.They are not cheap, about £65 plus vat and postage.All the best.
Foxy, August 2008