An update.
God bless those nice people at Norbury Wharf.
There were two problems which may, or may not, have been related.
The breather pipe was blocked with <use your imagination and insert word of choice>.
This would explain the dull booming sounds, trapped pressure being released etc and, assuming the red/green LED is worked by a pressure switch, the constant(ish) red LED.
Add to that the breather elbow on the tank had rusted through.
Iron fittings are, apparently, not the norm on PO tanks, plastic being more usual.
Is a PO tank a corossive environment for ferrous fittings? The tank itself is made from stainless.
What do y'all reckon team? Independent events or are they related?
Either way it's nice to have our old boat back, meaning one that no longer smellsl like an elsan tip!
SAM
Using the WiFi (and jolly good it is too!) in The Boat, Brewood.
Apologies, the pub is The Bridge, not The Boat.