Home Pressure Pump Systems
12V Pressure Pumps vs 230V Pumps
The question whether to use a 12/24 volt or a 230 volt pressure pump for a home pressure system is an interesting one.
The advantage of a 12/24 volt pump is that they are smaller and more energy efficient if you only want to run one tap or shower at a time. They typically draw 40 - 190 watts. You don't need an inverter to run them. The disadvantage of these pumps is that they have brushes and require more maintenance than a larger 230V unit. Most use diaphragms which makes them very efficient; however, they need periodic maintenance and the diaphragm may tear in abrasive conditions. See our range of 24 volt and 12 volt pumps.
The 230V pumps are much larger (usually 400 - 1000W) and they will run three or more taps at once. They are often cheaper than the 12V type. However, they would use more power and you could be without water if your inverter ever breaks down. You would need quite a large inverter to run the pump. This could add several hundred Watts of size to your inverter (when you consider that the pump will probably need to be on while the washing machine etc is on). This could amount to several hundred dollars extra for a larger inverter. If you choose a 230V pump we recommend a Grundfos household pump.
We encourage the use of header tanks as gravity is an efficient way to store energy. However, unless the tank can overflow during periods of oversupply you probably have an auto-close mechanism for your inlet pipe. These type of valves are commonly found in toilet cisterns and are known as ballcock or float valves.
A ballcock valve introduces some inefficiency into the system. The water needs to be 'forced' through the small opening in the ballcock valve. When the tank is almost full, this opening starts to close slowly or intermittently.
Another issue may occur when the tank is nearly filled; the ballcock can often "bob up & down" causing the pump to cycle on and off repeatedly. This causes more inefficiency as well as wear and tear on the pump. This problem is amplified when you use water while the tank is nearly full - the pump will try to refill what you just used.
You can address the latter problem by using a two level float valve which allows for a 400mm in the water level of the storage tank before the valve opens again. Also, in a large tank, the ballcock is less likely to "bob".
You can also solve these problems electronically, with a float or level switch that turns the pump off, rather than closing a valve.
Water Pressure Systems
Water Pressure Systems are required when you have a water tank at or below tap level (e.g. underground tank) or when you have a gravity fed system that doesn't supply sufficient pressure. You may create sufficient pressure by either pumping up to a header tank or using a pump with an automatic pressure switch and a pressure tank.
It is recommended to have at least a 20 litre accumulator (pressure) tank to provide a more even and constant pressure and to reduce wear of the integrated automatic pressure switch in the pump. The accumulator tank enables the pump to cope with a slow flow rate, such as when a tap is on partially and with a float valve when it is close to turning off. Without an accumulator tank the pump would switch on and off very rapidly.
It is also recommended to use a strainer or filter to prevent damage to the pump and to use 20mm (¾") water pipe or larger to guarantee a good delivery rate.
Testimonial from John Paoloni, Blue Mountains
"Just installed a 12V pump - works beautifully - have attached to the water tank, pump flooded with approx 6 metre head and feels no different to the 1200 watt Davey pump. Amazing that it only draws around 72 watts."
Warning: Pumps make some noise. Please think carefully about the position of a pump.