This booster pump sizing guide is designed to explain a few of the considerations you need to understand when choosing the correct booster set for your application. There are many others so do not hesitate to contact our team at firstname.lastname@example.org for advice on your next pump.
When sizing a booster set several fundamental calculations need to be taken into consideration so that the correct size and design of the pump is selected.
• The number of outlets in the system
• The pressure required in the system
• The location of the booster set
• Number of pumps required
• Type of control required
The flow rate can be estimated by a loading unit calculation. The British Standards Institute has a set load for each type of water outlet and by counting each item in the system a load calculation can be achieved. Use the table on this page to calculate the total loading units and check the result on the graph below.
Loading Units to Flow Rate Conversion Chart
Once a flow rate has been calculated from the graph, we need to decide what pressure the pumps need to run at. On a domestic or light commercial setup, a VARI BOOST or VARI TWIN would suit as it is designed to supply pressure to systems fitted with unvented cylinders. Both models include basic variable speed controls to suit numerous applications.
When buildings suit this type of booster set but the plant room location is small a PUK VARI TANK can be used to reduce the install footprint and free up valuable space. These units have the same control functions as the VARI BOOST and VARI TWIN booster sets.
If the set is to serve a large commercial system, the demand needs to be assessed so that the pump is not over or undersized. If the booster is in an apartment block or hotel the system will have demand spikes in the morning and evening when the services are used the most. Good practice would be to select 50% duty pumps so that energy is saved during the quiet periods.
The outlet design also needs to be considered. If the set feed taps on a riser and then a roof tank the set will need to supply small flows to the taps and large flows when the ball valve drops in the header tank.
The static height will need to be established and the pressure required at the highest point along with any frictional losses in the pipework. For these applications, we would size a PUK VARI COM booster set (WRAS Approved) as it has the control design to suit this type of system and the safety features to protect the pipework infrastructure.