4 min read

Understanding the Difference 

There are several benefits in using close-coupled pump sets when compared to conventional, long-coupled pumpsets. It is long-standing convention in the HVAC market to supply long-coupled pumpsets for chilled and condenser water reticulation. ‘Long-coupled’ refers to the method of mounting Bareshaft BPO pumps on a base, and coupling it to a separate motor with a spacer coupling. ‘Close-coupled’ refers to the design of an intermediate yoke which allows the pumps to have a direct connection to a standard metric frame flanged electric motor. Traditionally, these pumps were always more expensive than the conventional long-coupled pumpsets due to the greater volumes of Bareshaft pumps made for the world market. 

The long coupled pumpset has been challenged in recent years with increasing preference by site managers and contractors to utilise work methods such as prefabricated and pre-packaged products that minimise site labour and its associated risks.

Advantages of Close-Coupled Pumpsets 

• Compact design saving space in your plantroom – approx. 30% reduced floor space.
• Back pull out (BPO) feature is retained with close coupled pumps – repairs and inspections can still be performed without dislodging pipework. 
• BakerBloc close-coupled pumps still utilise standard metric frame motors, which are readily available in multiple brands across the country minimising downtime in the event of motor failure.
• Once delivered to site and installed, there is no need to have the coupling alignment checked, allowing your site manager to continue with the flushing, start up and commissioning of the system without having to coordinate the pump technician. This streamlines the whole on-site operation. 
• Close-coupled pumps enable smaller inertia bases, creating cost savings on your base as well as requiring less concrete, reducing carbon footprint.
• Reduced maintenance as two bearings are used, rather than four. 

Keep in Mind: 

There are two main pitfalls to look out for when assessing the use of close coupled options.

1. Are the offered pumps fitted with standard metric frame motors? The BakerBloc design passes this test. (some motor pumps are factory fitted with a motor produced by the pump manufacturer that is unique to the pump, resulting in expensive replacement)
2. Is the base design as such that the Back Pull Out feature is not compromised? Does the base design/length allow the motor to easily slide back for servicing? 

Maintenance 

For larger motor sizes, maintenance can still be streamlined if forethought is given to the placement of the overhead fixture for installing a block & tackle when servicing is required. The easiest and most cost effective way to specify the installation is to use a Dynaset, as supplied by Ramset. These are an internally threaded insert that require pre-drilling a 16 or 20mm hole (depending on Dynaset Model) in the concrete slab. The most common servicing task in the life of a pump is the replacement of the seal. This can be a one man operation for any size pump if the above matter is considered. 

How to Specify 

We suggest you incorporate the following clauses into your specification: –

“All close coupled pumps approved on this project shall have standard metric frame IEC electric motors fitted. Motors that are not interchangeable with readily available brands such as WEG, Teco, CMG, will not be accepted. Extended baseplates are to be sufficient length beyond the rear of the electric motor to allow motor and pump elements to be withdrawn sufficiently to allow service work on the pump to remove motor from off baseplate. The back pull out design shall not be compromised in any way. 

Motors shall be 3 phase T.E.F.C suitable for indoor/outdoor installation [Retain the correct item for this project] motor speed 24/48 [retain the correct item for this project] revs per second.

Pump construction shall be cast iron casing, bronze impeller and stainless steel shaft with mechanical seal fitted suitable for the liquid being pumped. Pump connections to be flanged for all connections 40mm and greater.

Installation considerations to be adhered to by the contractor: –

Gauge tapings/sockets or binder points to be installed on both sides of the pump to allow for future pressure drop readings across the pump. Isolation valves to be installed on both sides of the pump to allow for isolating the pump from the system during Hydrostatic testing and for future servicing.

For pumps with motor sizes 22kw and greater, an anchorage point shall be fitted to the ceiling immediately above the pump motor eyebolt. (Dynaset from Ramset or similar. Must be of sufficient load to take the weight of the motor) In the case of multiple pumps side by side, the contractor shall include the installation of an I Beam or similar for the client to be able to fit their own gantry block and tackle for future servicing and/or replacement. It is the mechanical contractors’ responsibility to ensure there is clear air space about the pump units – do not impede the easy removal of the pumping / motors for future servicing or replacement.

In addition to any automatic air release valves fitted, there must also be isolation valves at high point that can be manually opened to quickly discharge air from the system. These should be not less than 20mm. On systems that have an excess of 300 metres of piping, we suggest a 20mm valve (gate of ball) to be fitted at the first elbow above the pump on the discharge side.

Now that you know 

Considering the benefits of close-coupled pumps, you may be curious, or convinced, that they’re the right choice for your project. To take the next step, reach out to Masterflow to discuss the best configuration for your plantroom. Our specialist engineers will be happy to help.