Pump problems solved at sporting club

Perth’s Kingsway Sporting Complex is a hub of sporting and social activity. Proudly cared for by the City of Wanneroo, the complex includes sportsgrounds where cricket, soccer and rugby are played, and a stadium to cater for indoor sport and activities. Kingsway is part of the council’s aim to assist in the operations and sustainability of local sport and recreation clubs.

During the Kingsway ongoing redevelopment of playing fields and grassed areas, the City of Wanneroo was looking to improve its irrigation systems. Grundfos WA Account Manager Neil Cavalli says his involvement with the Wanneroo installation started back in 2007, when the company was asked to quote on a full Grundfos electrical and mechanical booster system for Kingsway.

“Consultants recommended the mechanical system (pump set only) and arranged to use an electrical system built by another company.”

Wanneroo initially installed five Grundfos CRN 90 pumps with 30 kW motors to deliver the required 139 L/s flow rate and then proceeded with their plan to have an external PLC (programmable logic controller) programmer write the software to control the Grundfos system.

But according to Wanneroo’s Technical Officer Irrigation, Jeff Lever, when the control system was originally commissioned the cascade control was not working correctly.

“The PLC - which had been programmed externally - would start all the motors at once and then stop them shortly after,” he explained.

“The system would overshoot the set point, running the system up to 14 bar instead of 7.5 bar ... pipes burst and we would be faced with extensive water loss and expensive repairs if operated.”

According to Lever, the system also wouldn’t deliver the expected flow rate.

“The pumps had to cope with multiple false starts per hour and an erratic and wildly fluctuating flow rate. Council needed a control system that would integrate with the pumps and ensure the pump station would operate correctly and efficiently.”

Cavalli says that after three years of problems with its irrigation system, the City of Wanneroo took ownership of the pump station and established a working relationship with Grundfos. Together, they redesigned and commissioned a control panel that would overcome their site issues at Kingsway. This was done by supplying a Grundfos MPC-EF controller to replace the existing, externally designed controller.

Specifically designed for cascade control of booster systems, the Grundfos MPC controller is built to handle the hydraulic challenges similar to that at Kingsway. The MPC control unit, specially designed for the Grundfos booster systems, is easy to operate from installation to everyday surveillance.

A Grundfos MPC can help conserve water when used in sportsground irrigation systems, adapting automatically to any number of sprinklers at any pressure zone during the irrigation cycle. It is suitable for mains water supply systems.

The main task of the MPC unit is to control the number of pumps in operation, as well as the speed of the individual pumps, in order to adjust the performance of the system to variations in demand.

With irrigation normally taking place at night where a higher pressure is required to supply sprinklers, it makes sense to lower the pressure during the day to save energy and water. This is managed through an automatic clock program with up to 10 clock-dependent set point changes for adaption to demand.

With Grundfos supplying the pumps and controller, the hydraulic data from the pump system is automatically stored in the controller. This makes it possible for the controller to calculate which pumps to run, conserving energy.

Additionally, the controller can be integrated with most common SCADA systems. It also has an ethernet connection so it can be operated from a remote computer where the operator is able to view the control panel on the computer screen.

Remote monitoring and data acquisition is also possible. Status on individual pump levels and system level as well as operating conditions, settings, control mode, warnings and alarms can be read out from a remote computer.

The Grundfos MPC controller has a built-in function that reduces the risk of pipework damage. Using the soft pressure build-up function, the system runs one or two pumps at a very low speed after it receives a start signal from the irrigation control. The pipes fill slowly and gently build up the required pressure, saving energy and reducing water hammer which, over time, damages the pipework.

The Grundfos WA team carried out the on-site commissioning of the new controls to manage the Kingsway irrigation system and everything now meets the specifications of the City of Wanneroo.

As soon as the MPC controller was installed at the complex, the system performed as expected. The starting and stopping of pumps is now carried out in a safe and effective manner, with the controller calculating the most efficient combination of pumps to run, at the correct speed, to reach the set point in the most energy-saving way.

Lever is happy his irrigation problems have been resolved. “We’ve gone from having a particularly unstable and inefficient control to peace of mind,” he said.

“We now have a Grundfos solution that automatically takes care of the pump control and a system that delivers exactly what we need when we need it ... and it is being done in a cost-efficient way.”

Council is now looking to improve the system in one area. To avoid any leakages during the day due to valves not shutting off, it will have its irrigation control system start and stop the Grundfos MPC Hydro Booster system during non-irrigation times.