If you own or manage a commercial facility, that is over 30 years old, you will need to repair or replace your cooling tower condenser water pump at some point.

As older pumps reach end of life, the building manager and service personnel face the daunting task of sourcing replacement pumps which will have an equivalent performance. With little information on file this task becomes even more challenging. Finding a suitable replacement pump is important because the risk in installing a pump that underperforms will compromise the comfortable atmosphere for the building occupants.

At Masterflow, we are well placed to help Facility Managers, Building Managers and HVAC Service Contractors to select a replacement pump of equivalent performance to their old equipment and successfully get their plant operating with minimum delay.

If your preference is to replace your pump with the same brand as you already have, then Masterflow may not be a good fit for you because we will draw from a variety of brands depending on the pump in question. You may prefer to reach out to the company registered on the pump nameplate, rather than source an alternative.    

Regardless of your preferred method, this article will guide you through the basic steps you need to take and the important information to look for in order to get a suitable replacement pump.

How do I replace my pump if the brand is no longer produced?

If your plant is very old, circa 1950s, there is every chance your chilled water pump or cooling tower pump will be a Kelly & Lewis Model 50 or an Ajax 3LS, Ajax 2LS or similar. These pumps are no longer produced. At Masterflow we have experienced pump engineers who will immediately recognise these types of pumps.

Even if your facility is circa 1960 or 1970s, you will most likely have the Kelly & Lewis Model 70 or Southern Cross RH Series or maybe an Ajax 2K. Again, these pumps have long been out of production. If your pump is from the 1980s and 1990s vintage, then you may have a Regent Din flow ,or Gaam Condenser water pump. Because these are the Back Pull Out Din24255 pump, they can be replaced without having to modify pipework. 

What information do I need to give the pump company? 

Once you determine that repairing your cooling tower pump is not practical, you will need to engage a pump specialist for a new pump. There is certain information you will need to supply.These are: –

1. A photo of the pump nameplate
2. A photo of the motor nameplate
3. An overall photo to the installation.

Your pump supplier will then be able make a selection and provide you a solution for a replacement pump.

How do I identify my pump if no nameplates?   

This is where it gets tricky. Some cooling tower pumps and chilled water pumps are so old and so weather beaten, that the nameplate is illegible or doesn’t even exist. In these cases, it is important to take numerous photos. At Masterflow we will offer to visit your site and inspect the pump and look at your application, to get an idea of the head and flow requirements. To help your pump specialist take the following photos:

1. Overall shot of the complete pumpset
2. Any casting number that are visible on the pump casing or bearing pedestal
3. If a C-Flex is attached clean and photograph the markings – this will indicate port sizes.
4. The nearest valve – to determine the inlet and outlet sizes of the pump in the absence of s C-Flex mentioned above.
5. TAKE A ROUGH Measurement OF THE PUMP CASING-this will indicate the approx. diameter of the impeller.

Will I have to modify pipework, or will it be a direct swap?

Generally, the older pumps will require pipework modifications. Especially if they are the side discharge type. Refer Figure 1.  Before the 1980s all pumps were pedestal mounted. That is, their bearing element is bolted to the base. But after 1980, the Back Pull Out pump became very popular. These pumps have feet integral to the pump casing. Refer to Figure 2. the History of Pumps in HVAC article for more information on older pumps.

A quick way to determine if pipework modification is required, is to identify he discharge branch of the pumps. Is it side discharges, or centre-line discharge. Refer to Figure 1.

If your pipework is copper or steel, then this will be a big issue. A plumber will need to be engaged. Plastic PVC pipework will be a lot easier to modify. 

Figure 1: Side Discharge (offset) .
Figure 2: Modern pump with Centreline Discharge.

What other considerations should I be aware of when putting a new pump into an old system?

Installing a new pump into an old system will mean things will change. Nothing worse than to start up your new pump and then have further unexpected problems. Here are a few we have come across over the years that we would like to share with you, to save you frustrations.

Electrical – your new motor may have a slightly different amperage draw than the old and may affect the performance of the starter or the circuits breakers.

Hydraulic – always make a note of the position of the isolation valves on the pump discharge of the old pump before you remove from service. Are they partially closed or fully open. If possible, take some pressure readings by installing gauges on suction and discharge of the pump. This will be invaluable if there a re performance issues after the new pump has been installed.

Valves: Old valves can be faulty. Always arrange for the valves to be upgraded at same time as a new pump is installed. Old valves almost never seal properly and water from the system form pooling in the plant rooms floor and presents a hazard.

Drains: in the event of the above, the old plant rom may have drains that are not clogged and thus over flooding can cause excessive damage to the floor beneath. Always arrange for a plumber to check the drains with electric eel before the new pump is installed.

Which is the best company to help replace my pump? 

Any pump company that has been serving the HVAC market for over 20 years will be well placed to help you with the replacement of your old cooling tower pump (condenser water pump)  or chilled water pump. So long as you are forthcoming with the information outlined above, the pump company will be able to assist you.

If the company advertised on the nameplate is still in business, they would also be a good place to help you, although you cannot assume they will be able to give you an exact like for like replacement, because pumps can change even though the brand is the same as the original. The pump company should be able to explain to you the differences, if any, between the new pump they offer you in comparison to the old pump being replaced.  

We at Masterflow may be a good choice. We are well placed to assist you having performed plant room upgrades and pump replacements for over 25 years. Furthermore, we have accumulated a vast library of old discontinued pump curves, having collected pump catalogues over decades.

For a list of very old pump brands & models including MLK Ajax, Southern Cross RHC type, Wajax Gaam and Dinflow refer to our Table of Common HVAC Pumps and their Current Day Equivalents which will help you identify your old pump.

Now that you have this additional knowledge, you now know what to provide your pump supplier in order to find the correct replacement of these older pumps. This article has guided you through the steps you need to take to find a replacement pump even if your existing pump is old and no longer in manufacturer.

To help you with replacing your existing equipment, fill out the Pump Replacement Form and submit to our helpful sales team.