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Buying Guides

Got your eye on something, but need a little help deciding? Terry, our resident MacGyver, has taken time out to put together some handy buying guides. If you need any advice, give us a call on 0800 800 880, we're always happy to help.

Water Pump Buying Guide

How to choose a pump and flow rate

When you choose your pump you need to figure out how many devices or appliances that use water could be operating at the same time. This is commonly known as "taps". For example, 3 taps could be your washing machine, a kitchen tap and someone using a shower or hose all at once.

To determine the flow you should also consider the distance from the water source to your pump, and from your pump to the required outlet of water - your home. Elevation, pipe size as well as bends will also reduce the flow rate. This is known as system friction a head loss.

What are the benefits of a pressure tank or controller?

A pressure tank will:

  • Use less power
  • Reduce wear and tear by eliminating unnecessary pump starts
  • Prevent burn outs by preventing low flow cycling. (dripping taps/tap being turned on and off quickly)
  • Eliminate pump failures because of water hammer

A controller will:

  • Protect the pump from damage using dry-run protection
  • Have adjustable pressure using a simple switch
  • Protect plumbing by regulating the pressure
  • Be easy to install and is nice and compact
  • Provide constant reliable pressure

We recommend the use of a water hammer arrestor with any system. Especially with filter systems and UV. Pumps should also always be protected from power surges.

What size tank should I get?

For most average size houses we recommend a tank of no less than 50L. And the general is always bigger is better. A pressure tank only holds about 1/3rd of the tank's capacity at pressure. The bladder in the tank tends to last about 40,000 cycles, so the less it cycles the better.

Average water requirements:

Cottage or Bach: 1 bathroom - 1-2 taps
15-20 litres per minute

Small Home: 1 bathroom, single storey - 2+ taps
30-40 litres per minute

Typical Home: 1-2 bathrooms, single storey - 3-4 taps
40-50 litres per minute

Larger Home: 2 bathrooms, 2 storey - 4+ taps
50-70 litres per minute

Large Home: 2+ bathrooms, 2 storey, multiple appliances - 5+ taps
70-110 litres per minute

Large Building: Multiple bathrooms, appliances and levels - 6+ taps
90-250 litres per minute

What maintenance do I need to do?

The best thing to do is to check your tanks every month just to make sure you’re not loosing pressure. Re-Pressurising should be only necessary about every 4-6 months, at the most. More than likely, the bladder will need re-pressurising or have broken. With our tanks, you can buy a replacement bladder for much less than the cost of replacing the tank.

To replace a bladder, simply let the air out using the air pressure relief valve, and then undo the unit at the base. The bladder should come out easily. It’s best to give the tank a good wipe to remove any surface rust, and then let it dry thoroughly. Then simply insert the new bladder, close the unit and bring back up to pressure.

I can buy a cheap tank - are these ok?

Yes of course, but we urge you to ensure that the bladder is EPDM rubber if coming in contact with drinking water. All Trade Tested bladders are certified as EPDM. Cheap tanks often use non EPDM rubber, and this can be unsafe as chemicals used in the manufacture can leak. But don’t worry. We don’t sell any ones like that. So you’re looking in the right place!

If you have any more questions just give us a call 0800 8008880 or send us an email.