New pumps for old

Glynn Williams of Grundfos wonders why there is such a laissez-faire attitude towards replacing aging pumps — given the huge benefits offered by modern pumps.

So you have a pump(s) that needs to be replaced? That’s an easy one isn’t it? Just look at the pump plate, take down the relevant details and order the same again. Right?

If you were to look at a pump as a highly engineered, ever-evolving technological solution such as a mobile phone or television, you wouldn’t begin to consider buying an identical replacement to a version you had purchased over 15 years ago. You would want to opt for a new model, complete with all the in-built advances, improved design and better efficiencies. This should also be true when looking at replacing a pump or pumps.

Unlike other equipment, it is very rare for anyone to consider exchanging a pump unless it has developed a problem that means it is at ‘end of life’. This is true even though changing a pump(s) could lead to huge energy savings that would mean the pump equipment would have quickly paid for itself through lower energy bills in a very short time period.

Working out the efficiency of current pumping solutions can be complex, which is why Grundfos has developed a wide range of tools — including the Pump Check and Pump Audit — that can assess the performance of a current pump installation and make firm tangible recommendations.

In terms of making the right decision about replacement, an important consideration is whether the pump is suitable for the current duty requirements? The pump may be oversized, and nameplate information may not reflect the original design duty or the current operating duty and, hence, the replacement duty requirements.

It may also be the case that the original design allowed for a 10% margin increase in flow and subsequent 20% in head, which would have an impact on the energy consumed should this allowance be no longer required. This can easily be engineered out again by reducing pump speed; remember reducing a pump’s speed by 20% will reduce the energy consumption by 50%.

Another factor is to check if the building has changed its configuration and/or use since it last had an M&E fit-out — or, indeed, is about to change its use. Such factors can have a major impact on what pumps and pump duties should be considered. In particular, it is important to look at changes that may require additional pumps being added to the requirement. For example a change of use that results in more compact living may require additional water boosting.

Heating and cooling circulator pumps form most of the replacement market. New pumps offer greater efficiencies than previous generations, but to gain maximum energy and CO2 benefits variable-speed options should always be considered. Today’s preferred choice for variable-volume systems often include permanent-magnet circulators (such as the Grundfos Magna1 and Magna3) as they deliver significant energy savings over older-style pumps because they adjust themselves to the demands of the system.

Grundfos Pumps, pipes, pipework
Modern pumps offer so many benefits that it is well worth planning replacement before ‘end of life’.

A benefit of selecting a more modern design is that it facilitates easier replacement of wearing components. Choosing a manufacturer which can support service requirements for the long term is important, as they will maintain a wide range of dedicated service kits and replacement motors that will often be available ex-stock.

An additional option to increasing efficiency is to opt for a member of the Grundfos CUE range of wall-mounted frequency converters that can operate with centrifugal pumps in both new and existing applications. Such fully integrated energy-efficient solutions provide pump, frequency converter, controller and sensor — all perfectly matched and configured to specific pump installation needs

The overall condition and configuration of the pipework is another aspect to be considered and can affect the choice between being able to opt for in-line or end-suction style products. The plant room configuration and access is another aspect, as access is important, and sufficient space needs to be allowed if cranes or hoists need to be used. The state of the system pipework will also be an ultimate factor in the choice of route that can be taken. Further reading/guidance is available from recognised authorities such as BSRIA on www.bsria.co.uk.

An end-of-life a pump is not a piece of worthless scrap; on the contrary it is still a valuable resource. For example, 90 to 99% of the materials in a typical Grundfos pump are recyclable when dismantled and separated.

There are huge benefits to being in control of your pump replacement as this means that timings and expenditure can be planned. Asking the right questions and not necessarily waiting for ‘end of life’ in terms of contemplating a pump replacement can offer a wide range of benefits that may not be immediately obvious. The potential return on investment is significant and is something that should be part of a systematic approach to improved plant equipment, increased efficiencies and lower overhead costs.

Glynn Williams is director of sales for commercial building services with Grundfos Pumps.

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