watchman

Can anyone advise if a Watchman Sonic oil tank monitor can fit the hole used for an old Sensor Systems Niveau Watchman? I want to replace the old hardware and the new Watchman Sonic needs a 32mm hole. Obviously I'd rather not have to drill a new hole. I don't have access to the tank at the...

Watchman Plus plug monitor showing “r” so replaced 4 x AAA in power tube and measured 6.3V at connector. After switch on, monitor displays serial number then remains on “r”. I have carried out battery replacement before, with no problems. Any ideas where to look next? Cheers