Unit 308 session 8 Shower pumps

​Installation of shower mixing valves and shower boosting pumps

​Most showers can be operated by using the head of pressure between the shower head and the cold water storage cistern.
This is known as 'Gravity fed'

​However there are circumstances where we may wish to pump our shower supply?

Open Ended

Why do you think we may need to pump hot and cold water to a shower instead of using the head of pressure from a storage cistern?

​Sometimes there is not enough head of pressure to give an effective flow rate.

​ In certain circumstances the shower head may be higher than the storage cistern.
(Negative head)

Open Ended

As previously mentioned you may come across a system where the shower head needs to be higher than the storage cistern (Negative head) Research how you could overcome this problem.

(Please do not cut and paste answers, and you can add pictures if required)

​Shower pumps

Low-pressure shower valves can have boosted hot and cold supplies by the use of shower boosting pumps. There are two types available:

1 Single impeller outlet pumps:

this type of pump is designed to pump hot or cold water to individual outlets such as hot or cold water taps throughout the property.
They were commonly installed after the shower mixer valve to boost the mixed water to the shower head, however it can sometimes be difficult to install them as per the manufacturer’s guidelines in this way, as such twin impeller pumps have become more common to boost the water to the mixer valve.

​2 Twin impeller inlet pumps:

these are fitted before the mixing valve, and boost the individual hot and cold supplies to the valve where the water is mixed, or if the correct pump is selected, can also supply hot and cold water to the whole house.

They have a single electric motor, which drives two impellers (hot and cold).

Care should be taken when installing the pipework to ensure that it meets the manufacturer’s specific requirements with regard to pump position, pipe size and minimum head of water required.

​Click on the link below and answer the questions on the following slides.

The_City_and_Guilds_Textbook_Plumbing_B......_----_(6_Hot_water_systems) 71-74.pdf

Multiple Choice

What type of mixing valve is considered the safest to use with cistern-fed supplies due to its ability to maintain a constant temperature irrespective of the volume and pressure of incoming hot and cold water supplies?

• Manual mixing valve

• Thermostatic mixing valve

• Pressure-balanced mixing valve

• Diverter mixing valve

Multiple Choice

What is the term used to describe the layering of water by temperature within a hot water storage cylinder, from hottest at the top to coolest at the base?

• Condensation

• Stratification

• Segregation

• Insulation

Multiple Choice

What is the purpose of using a shower booster pump with cistern-fed supplies in the installation of shower mixing valves?

• To decrease the water pressure

• To filter the water

• To increase the water pressure

• To heat the water

Multiple Choice

What is the minimum head required for a pump when using a 'deluge'-type showerhead, according to the text?

• 150 mm

• 1 m

• 150 cm

• 1.5 m

Multiple Choice

What is one of the obvious advantages of using an unvented hot water cylinder for shower mixing valves?

• It requires a booster pump.

• It provides a more forceful shower.

• It operates at a higher pressure than the mains cold water supply.

• It needs a special fitting called an Essex flange.

Multiple Choice

Why do showers installed on instantaneous water heaters and combination boilers require a shower valve that is pressure compensating?

• To ensure equal hot and cold pressures.

• To prevent the shower from turning on automatically.

• To increase the water flow rate to the maximum.

• To reduce the overall water consumption.

Multiple Choice

What happens to the cold water as it passes through the hot water heater/combi boiler?

• It gets filtered for impurities.

• It loses pressure and flow rate.

• It bypasses the heating element.

• It causes the heater to shut down.

Multiple Choice

What does the pressure-compensating shower mixer valve do to provide a powerful shower?

• It heats the water to a higher temperature.

• It adjusts both pressure and flow rate within the shower valve body.

• It reduces the cold water flow to increase pressure.

• It only increases the flow rate of hot water.

Multiple Choice

How does a thermostatic mixing valve ensure safety in shower systems?

• By automatically shutting off the water flow if cold water supply fails.

• By increasing the water temperature to eliminate bacteria.

• By reducing the water flow to conserve energy.

• By filtering out harmful chemicals in the water.

Multiple Choice

What feature of a pressure-balanced mixing valve prevents scalding when there is a sudden drop in cold water pressure?

• It shuts off the hot water supply.

• It compensates by reducing the hot water flow.

• It increases the cold water flow to balance the temperature.

• It alerts the user via an audible alarm.

Multiple Choice

Why is it important to have a non-return valve installed with a shower mixing valve?

• To prevent backflow of water into the mains supply.

• To increase the flow rate of water to the showerhead.

• To regulate the temperature of the water more efficiently.

• To reduce the noise generated by the water flow.