Grundfos CMB SP (CM Booster SP PM2)

Grundfos CMB SP (CM Booster SP PM2)


Dwelling Size Number of Taps Pump Model Recommendations
Small House 2-3 taps CMB-SP 1-36, CMB-SP 3-28
Medium House 3-4 taps CMB-SP 3-47, CMB-SP 3-37
Large House 4-5 taps CMB-SP 5-47
Large House

(long runs of pipe)

5-7 taps CMB-SP 5-47, CMB-SP 3-56
(Taps are 15 l/min at 22.5 m head, please note: pipe friction and other factors will affect this)


Grundfos CMB-SP Spec Sheet 


  • Mains Boosting
  • Water Pressure boosting from above or below ground tanks

Price includes GST and is freight free within North Island and South Island of New Zealand

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Grundfos CM Booster SP PM2

Industrial Quality, Self-Priming Pressure Booster

The Grundfos CM Booster PM2 Self-Priming is a heavy-duty, premium water pump that’s designed to move rainwater or increase the pressure of your home’s water, whether the water is coming from tanks above or below ground.

Here’s what we think is great about this pump:

  • It can pull up water from below. The CM Booster Self-Priming is designed to suck up water from up to 4 metres below it. And if you install a foot valve, it can pull up water from as far as 8 metres below.
  • It has an automated control and ongoing protection. It comes with a sturdy controller that helps manage the pump and offers a high level of customizable safety features to help preserve the pump whilst delivering you your water at a good pressure. 
  • It’s industrial-quality. This means it’s designed and built to handle big jobs, so it can easily manage a large home’s water supply, or boost the pressure of water coming from the mains.
  • It’s quiet. It won’t make a lot of noise that might disturb you, your family, or your neighbours. It clocks in at 55 db, which is a similar sound level to a running dishwasher.
  • It’s made of superior materials. The pump is made from high-quality, industrial-grade parts. All the parts in contact with the water are made from 304 stainless steel.
  • It’s easy to install. Just connect the pump to your pipes, get the pump ready (this is called priming), plug it into an outlet, and it’s ready to go.
  • It comes with a PM2 Pressure Controller.


The PM2 Controller is a type of control system for a water pump. It lets you adjust when the pump starts, anywhere from 1.5 to 5 bars of pressure. This means you can tweak it to work best for your specific application if required. You can also set it to maintain a 1 bar difference between when the pump starts and stops if you’re using an external pressure tank.

Here’s how it works: There are little switches, called DIP switches, behind the control panel. You use these to set the pressure at which the pump starts. There’s also a display on the front of the PM 2 that shows the current pressure.

Once the pressure reaches the level you’ve set, the PM2 starts the pump. The pump keeps going as long as the water is flowing.

If you’re using an external pressure tank, you can make the PM2 work even better. There’s a function that maintains a 1 bar difference between the pressure at which the pump starts and stops. This function can help the pump run for fewer hours, which is great for setups that use a pressure tank.

The PM2 also have some safety features to protect the pump and the whole system:

  • Dry-running protection: This keeps the pump from running when there’s no water, which could damage it.
  • Cycling alarm: This alerts you if the pump starts and stops too frequently, which could indicate a problem.
  • Maximum continuous operating time: The pump automatically turns off after running for 30 minutes straight to prevent damage. This feature also helps with saving your water too if a pipe were to burst or if a tap was left on accidentally. 

Also, the PM 2 can automatically restart the pump with its auto-reset function.

Here’s what other customers like about this pump: click here to read updated customer reviews

CM Booster SP Pump Performance Curve Showing the Different Models:

How does a pump performance curve help me? Here is a simplified explanation:

A pump curve shows you what a pump is capable of – how much water it can move (flow) and how high it can lift it (pressure). The horizontal line on the chart is for the water flow, and the vertical line is for how high the pump can push the water. But remember, the pump’s job gets tougher if it needs to push water up high or through filters, fittings and pipework that create friction or drag. This ‘eats up’ some of the capacity, meaning the actual outcome at your tap could be different. The pump curve can be your initial starting guide to finding a pump that’s strong enough to give you the right water pressure and flow, after all these factors come into play.

Physical Attributes & Dimensions:


Operating Conditions & Technical Data

FAQ – What is the difference between this pump, the CM Booster SP (Self Priming) and the CM Booster? The main, notable difference is that the CM Boosters cannot create suction by themselves, which means they would not be suitable in applications where the pump would need to suck water up from a water source below it, whereas the CM Booster SP can (4M vertically below the level of the pump, or up to 8m with a foot valve). The CM Booster SP also comes with a PM2 Controller instead of a PM1, which has less features.

If you have any questions on this product, don’t hesitate to contact us for help with finding the right product or variant for your application. If you are local, pop into our store to see our pumps on display, and to have someone assist you in finding the right sized pump for your set up. We are located at 72 Kioreroa Road, Whangārei 0110. If you are not local and have a question, you can fill out the form below.

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Additional information


CM Booster SP 3-28 PM2, CM Booster SP 3-37 PM2, CM Booster SP 3-47 PM2, CM Booster SP 3-56 PM2, CM Booster SP 5-28 PM2, CM Booster SP 5-47 PM2