There is no fixed number; a building's pump should only run when water is being used. The normal pattern, the signs of running too much, and how to cut the pump's running hours.
"How many hours a day should a water pump run?" has no numerical answer, because a building's pump doesn't work by the clock; it works by demand. The pump controller starts the pump when the pressure falls to F2 and stops it when the pressure reaches F1. So the pump's daily running hours are roughly the time during which water is being used in the building.
The normal pattern
- At night and in low-use hours: the pump is off most of the time. If you have a healthy pressure vessel, short draws are supplied by the vessel and the pump does not start at all.
- At peak hours: the pump is on more and may run for a while without a break. This is normal.
- When all the taps are closed: the pump should bring the pressure up to F1 and stop. If F8 (stop delay) is not zero, it stays on for those few seconds after reaching F1; the factory setting of F8 is zero.
Signs of running too much
- It doesn't stop with all the taps closed: the pressure doesn't reach F1 or there is a leak somewhere. The causes are in Why does the water pump run non-stop?
- With no water in use, it starts and stops every few minutes: this is cycling, not demand; the causes are in Why does the water pump keep starting and stopping?
- It gets hot: running for long without enough water, or beyond the pump's capacity, heats the motor; see Why does a water pump overheat?
How to cut the pump's running hours
- Find the leaks. A dripping tap or a toilet cistern that lets water through keeps the pump running for no reason. The simple test: close all the taps, note the pressure on the display and read it again a few minutes later; if it has dropped, there is a leak somewhere.
- Don't set F1 higher than you need. A pump that has to reach a higher pressure runs longer. The right figure for each building height is in How many bar of water pressure does a building need?
- Keep the pressure vessel healthy. A vessel with the right air charge answers short draws without the pump starting; check the pressure vessel pre-charge once a year.
Power use
Because the pump's running hours depend on the building's use, its power use is not fixed either. For an estimate, multiply the power on the pump nameplate by the running hours. There is more on this in How many amps does a 1 hp water pump draw?
By switching the pump on and off according to the actual line pressure, the HYDROSET pump controller makes the pump run only when it is needed. See how the pump controller works in the simulator.
