‘If your water pump used to cycle but now runs all the time, a mini-pump may have failed’
Technical Consultant I RECENTLY READ about a boater who thought his water pump was faulty because it ran all the time he was showering.
These pumps have a certain output capacity (volume of water) at 12v and, when a tap or shower valve is open, a certain volume will flow; if that volume is lower than the pump capacity, the pressure in the system will rise until the pump turns off. Then, when the pressure drops, the pump will cut in again.
This is cycling and can be normal. If the volume that flows is more than the pump capacity, the pressure in the system will drop until the flow equals the pump delivery and the pump will run all the time.
An accumulator, if fitted, does not alter the above, it will simply alter the frequency of the cycling. If your pump used to cycle but now runs all the time an outlet is opened, it probably means that one or more of the mini-pumps inside the main pump have failed.