Pump Motors

Shower pump motors are the electrical powerhouses within shower pumps, responsible for driving the mechanisms that boost water pressure to your shower head. In homes with "gravity-fed" water systems (where you have a cold water tank in the loft and a hot water cylinder, often in an airing cupboard) the natural water pressure can often be quite low, leading to a weak or inconsistent shower. A shower pump with its motor is installed to overcome this by actively increasing the flow and pressure of water.

Regenerative Pumps: Water enters the pump, and the impeller spins it around inside a casing, building pressure as it circulates. A "stripping block" then directs the pressurised water out.

Centrifugal Pumps: Water enters the centre of the impeller. As the impeller spins, centrifugal force pushes the water outwards, building higher pressure within the chamber before it's forced out of the pump. Centrifugal pumps are generally quieter and more flow-efficient.

The motor itself is usually a continuous-rated electric motor, but the type of pump it drives and how it's configured depends on your plumbing system:

Single Impeller: These pumps have one impeller and are designed to boost a single water supply, either hot or cold. They're sometimes used to boost hot water to a mixer shower where the cold water is already at good mains pressure or to boost cold water to an electric shower.

Twin Impeller: This is the most common type for mixer showers. They have two impellers (driven by the same motor) boosting both the hot and cold water supplies simultaneously and equally. This ensures a balanced flow and temperature from your mixer shower.

Positive Head (Gravity-Fed): These pumps rely on gravity to create a minimum flow of water into the pump to activate a flow switch. For a positive head pump to work correctly, the shower head must be at least 600mm (or often 1 metre) lower than the base of the cold water storage tank. This is common in homes where the cold tank is in the loft and the shower is downstairs.

Negative Head (Universal) / Suction Pumps: These pumps have a pressure sensor that detects when the pressure drops (i.e. when a tap or shower is turned on) even if there's no initial gravity flow. They actively "suck" water from the tank to start. Negative head pumps are essential when:

Regenerative Pumps: Often more compact and typically cheaper. They can be a bit noisier due to the way water is circulated around the impeller.

Centrifugal Pumps: Generally quieter and more efficient, especially for higher flow rates or multiple outlets. They draw water into the centre of the impeller and use centrifugal force to push it out.