Fortyodd said
Also, if the Transfer Pumps are switched off the captions are ON -"
I don't think this is correct, ref AAIB report:
"An algorithm is built into the CPDS software to prevent intermittent fuel transfer pump captions appearing during dynamic manoeuvres in flight, as the fuel moves about in the main tank. This inhibits the caption until there has been a continuous period of three minutes during which the pump has run dry. If, within the three-minute period, the pump becomes re-immersed in fuel, the three-minute delay is reset to zero to await the next dry running condition. The f pump aft and f pump fwd caution captions will also illuminate after three minutes if the fuel transfer pumps are switched off while immersed in fuel or become blocked.
A message is not provided for the situation where a pump has been switched off, after running dry, and is then re-submerged in fuel.