grace said
We have owned our 70ft boat for less than a year and drained the water system during the winter as we do not live aboard. We spent a few days on board a week ago and refilled it with no problem but noticed that afterwards the water pump was repeatedly topping up the pressure about every 20 minutes when we had not used any water. We thought there might be a water leak and checked all the pipes we can see but couldn’t find anything or hear anything dripping. Could it be a problem with the pressure vessel?

Can anyone more experienced suggest what to try?

Remember the pressure accumulator has a membrane within that is user pressurised with a bicycle pump via its Schroeder valve, so it may need pumping up a tad to stop pump cycling against its lower pressure.

Even then its not unusual for pump to run briefly once or twice a day as the temperature changes within boat and hence accumulator pressure.

As Crosswind suggests though have you bled all air from the system by running each tap for a while. Don’t forget the dumpthrough loo if you have one either.