Pump Spotlight: Grundfos ALPHA2 N

The ALPHA2 N is an energy efficient variable speed, stainless steel, secondary hot water domestic circulator. Offering instant hot water in single and multi-family housings in the most cost-effective way.


With its stainless steel housing the ALPHA2 N is designed for use in hot water re-circulation systems to ensure hot water is available throughout the system.


  • High efficiency permanent magnet motor
  • WRAS approved
  • Choice of variable speed and fixed speed operation
  • Quiet operation, minimal system and valve noise
  • Unique ‘Plug and Pump’ electrical connection for speedy installation
  • LED display shows power on and electrical usage

The Pump Spotlight

Choosing the correct pump is no easy task, non-specialists may often be overwhelmed by industry terminology and the endless options available.

There are many factors to take into account such as:

  • What fluid will the pump be dealing with?

This is one of the most important factors when selecting a pump, by identifying what pump is appropriate for handling the fluid at question, corrosion and unnecessary wear and tear on your pump can be avoided. What’s the consistency? Is it a slurry (thick suspension of solids in liquids), or is it a clear fluid?

  • Flow rate

To accurately select a pump, it is imperative that you know the flow rate. Measured in gallons per minute (GPM), although this may be translated into the pump diameter measurement. A higher flow rate, means a larger pump size is needed.

  • Viscosity

The viscosity of the fluid is also an important factor to take into account, high viscosity fluids require most robust pumping equipment.

  • Temperature

How hot will the fluid being pumped be? The temperature of the fluid will affect which pump materials are best suited for the application.

  • Pressure

Taking into account the pressure conditions on the inlet and outlet of the pump will also help determine what pump materials are best suited for the application.

Sourcing all of this information and comparing it with product offerings from many manufacturers may seem a very daunting task & 9/10 times it is best to speak to a specialist even if it is just for reassurance. However, it is still useful to be aware of different product ranges and what applications different pumps are suited for.


That is why we’re excited to reveal that we’ve teamed up with our Industry Partner, Grundfos to grant you with the ‘Pump Spotlight’ designed to give you a deeper insight into different pumps from the Grundfos product range.

  •  Find out which pumps from the product range are best suited to your desired application.
  • Determine the features of the vast Grundfos pump product range.

We will be bringing you one pump in the ‘spotlight’ every Friday, so keep an eye on the Cougar Pumps blog.



Mechanical Seals

Mechanical seals are used to prevent liquid from leaking out of pumps, between the rotating shaft and the pump casing.

Earlier pump models may use mechanical packing (otherwise known as Gland Packing).

If you’re wondering why your mechanical seals keep failing, then this blog post can assist you in advising 5 possible reasons as to why this may be occurring and how to overcome the issue of failing mechanical seals.

1.The pump has been ‘run dry’

Not only does this have an impact on mechanical seals, but this can affect other areas of the pump such as the impeller. Running pumps dry can cause the impeller to melt along the shaft, causing the impeller to seize onto the shaft.

2. Heat caused the o-rings to deteriorate

3. The seal materials were attacked by the fluid being sealed

4. There is an operator error

Skipping initial start-up procedures are a big factor when it comes to mechanical seal failure. Improperly starting the pump can cause the motor to trip and the shaft to twist causing undesirable orbit movement.

5. The wrong seal has been installed or the seal has been installed incorrectly

So now you know what might be causing Mechanical Seal failure, but what can you do to avoid failure?

1. Choose the correct seal

Lack of knowledge and information will only cause obstacles in the seal selection process. Before deciding on a seal, you should carefully consider the application and operating conditions. It is highly likely that you may need to speak to a specialist to ensure the information yo have obtained is accurate, or even to obtain the information required.

2. Properly install the seal

Mechanical seal installations should be performed using the specific steps outlined by the manufacturer, taking care to avoid damage to the seal faces and / or O-rings.

Seeking assistance from a specialist to do this is also likely to be necessary.

3. Prevent excess heat generation

Excessive heat generation between seal faces can drastically reduce seal life. Dry running should be avoided at all costs. Dry running typically occurs when a pump is flooded or the seal chamber is incorrectly vented before pump start-up.

4. Maintain proper storage conditions

Mechanical seals are composed of many unique parts and a variety of materials. Because of the diverse properties and precise nature of these components, it is imperative to understand how long a seal can be stored safely without compromising function.

Should you require any further advice on how best to store a seal, or need assistance installing mechanical seals, get in touch.