FAQ - Choosing the right Pump

Kia ora and welcome to the FAQ’s (Frequently Asked Question’s) section of the Manaia Water Products NZ Website. Choosing the right pump for your situation can be a daunting process to the newbie, so we’ve put together a guide to cover off the specifics of making an appropriate selection.

Pump Selection:

You will need to be aware of a few things when making a pump selection. We will endeavor to explain them in some detail.

  • Water requirements

  • Pressure requirements

  • Flow requirements

  • Type of pump

  • Type of controller

 

Calculating water usage?
 

Use the following figures to assist with calculating how much water each outlet supplies in domestic applications:

 

Toilet: 9l/min

Shower: 10-15 l/min

Water-Saving Shower Head: 6-7 l/min

Household tap: 10-15 l/min

Dishwasher: 15 l/min

Washing Machine: 10-15 l/min

Garden Hose: 20 l/min

Lawn Sprinkler: 10-15 l/min

Alternatively, use the below guide for typical domestic water usage:


Small Cottage/Bach: 10 – 20 Litres per minute
Small House: 20 – 30 Litres per minute
Medium House: 30 – 50 litre per minute
Large House: 50 – 90 litres per minute.

What pressure do I need?

In most homes, the water pressure is between 40 - 70 psi


To work out the pressure required for an application, answer the following questions:

What is the height difference between the pump and the highest point of use?

What is the distance between the pumps location & the furtherest outlet?
Is there any pressure already available? Positive suction?
What size, type and length of pipe is being used from the pump to the final destination (pipe friction loss)?
What is the required pressure at the tap/shower, sprinkler? If known
What is the water source (bore, well, rainwater)?
What power supply is available (240V, 415V)?
If you need assistance with calculating these requirements, please contact us on 021 626 186 or email sales@manaiaproducts.com

Which type of pump should I choose?


Why choose a Jet Pump?
if you need to draw water up out of a tank, well or other water sources. Jet pumps are an ideal option. Jet Pumps are self-priming which means they are capable of drawing water from 7-9m below the level of the pump. Jet pumps are fitted with a jet and venturi and is the main reason as to why they have such high suction capability. Remember that pressure and flow are diminished when the suction height is excessive. Jet pumps tend to be a bit noisier than a multistage pump but are a necessity when suction lift is required.

 

if you’re dealing with an application where the water source is below the level of the pumps inlet connection then selecting a jet pump would be the best option

Why choose a Multistage Pump?
Multistage pumps are an option to consider and work well when there is a positive head of pressure available to the pump. Positive head pressure occurs when the water supply is above the level of the pump and is ideal for installing a multistage pump. These types of pumps utilize multiple impeller and diffuser assemblies (stages) that increase the pressure & flow from the pump.

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Electronic Pressure Controllers – What are they and how do they work?

Electronic pressure controllers are devices used to control and protect a pump in a system. The operation of the controller is to detect the pressure drop, in turn signaling the pump to start. Once the maximum system pressure is reached the pump shuts down by detecting no flow. These operations are controlled by a magnetic reed switch and flow valve in the controllers' assembly.

 

Adjustable pressure controllers:

These types of controllers allow users the ability to change both cut-in & cut-out pressure settings via push button control. These controllers are best suited to applications when there is a need to work within a specific pressure range but will require a pressure tank to be installed.

Pre-set pressure controllers:

 

Manaia Water Products NZ have available the Bianco nXt & WHI-SK series of electronic pressure controllers for sale. For further information please refer to the link below:  

 

https://www.manaiaproducts.com/controllers

Why a Pressure Tank? (Cell)

Pressure tanks can be fitted with both electronic pump controllers and mechanical pressure switches.

Benefits of adding a pressure tank:

  • ​Holds a reserve of water that is readily available to the system and constant when an outlet is opened.

  • Minimizes pump stop/starts thus extending the life of the pump in turn reducing wear & tear on moving parts.

  • Reduces power consumption by drawing from the tank's water reserve before activating the pump.

  • Prevents water hammer.

  • Allows a greater range of operating pressures within a pump's optimum performance range

Installing a Reflex Pressure Tank aids any water supply system by offering pump longevity, versatility, power savings, and $$$