A rainwater pump that keeps starting with all taps closed is often responding to water use or pressure loss you cannot immediately see. A leaking toilet inlet, an irrigation connection or water slipping back through a non-return valve can make the controller think water is needed again.
It is not necessarily the pump turning itself on at random. With an automatic water-pressure pump, the useful question is: what happened to the pressure after the last time it stopped?
Questions answered in this guide
Can something be using water when no tap is open?
Yes. Think about everything connected to the tank, not just the garden tap. A toilet can quietly refill, an appliance can take water during a programme, and a float valve can top up another tank or trough.
A cistern that leaks a little into the bowl is particularly easy to miss. Nobody has flushed, but the inlet eventually opens to replace what was lost. From the pump's point of view, that is genuine demand.
Davey's home pressure-system manual lists leaking taps, float valves and check or foot valves among the causes of frequent cycling. It also notes that float valves filling tanks can sometimes produce this behaviour.
Before assuming a component has failed, note what the tank actually supplies. A pump connected only to one garden hose presents a different puzzle from a system feeding toilets, laundry and irrigation.
Why can it happen without a visible puddle?
Pressure loss is enough to trigger an automatic pump: DAB explains this principle in its anti-cycling guidance. A non-return valve is supposed to let water travel one way. If it leaks backwards, pressure can fall within the pipework without water spilling onto the ground. The controller may then start the pump to restore it.
That explains why āI've looked around and can't see a leakā is useful information, but not proof that the plumbing is holding pressure. Water disappearing into a toilet bowl or returning along a pipe is less obvious than a dripping hose connector.
A technician can separate those possibilities by testing the system. You do not need to dismantle a valve to provide a helpful description: whether the starts happen with all known outlets off, how long each run lasts and whether water pressure at the tap has changed.
Is rapid cycling while I water the garden the same problem?
Not necessarily. A pump that starts periodically when everything is off has a different pattern from one that rapidly stops and starts while you deliberately draw a small amount of water.
In a system using a pressure vessel, that vessel provides a small reserve of water between pump starts. If its condition, charge or size is unsuitable, small demands can lead to frequent starts. Other controllers manage demand differently: Davey's Torrium 2 description, for example, explains its built-in accumulator. Do not assume every automatic pump has a separate air-charged tank.
This distinction helps avoid the wrong fix. A problem that appears only with a dripper running very slowly deserves a discussion about the system's low-flow operation. An otherwise unused system that starts through the night deserves a search for hidden demand or pressure loss.
What should I tell the pump technician?
Give a short account of a normal evening: āAll taps were off, no appliance was running, and the pump started for a few seconds every few minutes.ā Or describe the opposite pattern: āIt stays off overnight, but cycles whenever the dripper line runs.ā
Include any recent changeāa new irrigation line, toilet repair, filter service or very low tank level. A photo of the pump and controller labels is more useful than guessing which internal part needs replacing.
Keep electrical housings closed and leave pressure-vessel adjustments to a competent technician. If the unit is running continuously without delivering water, overheating or repeatedly faulting, stop it using its normal control and arrange service rather than repeatedly resetting it.
Will replacing the pump stop it?
Only if the fault is actually in the pump or its control equipment. A new pump connected to the same leaking cistern or faulty non-return valve can repeat the same behaviour. Find where the demand or pressure loss comes from before paying for a replacement.
