Installation of a Custom High Pressurisation Unit
We were recently asked to replace a chilled water pressurisation unit in an office block in central London. The old pressurisation unit that was installed had failed and the parts were obsolete.
The pumps in the existing unit produced a static head pressure of 10 bar as this is what was required for the chillers to run. Due to the high-pressure requirement, we decided to build a bespoke PUK Autopress HPO unit to suit.
We selected two Lowara multistage pumps to construct the unit with as they allowed us to reach the closed valve pressure. To construct the unit, we secured both pumps onto a prefabricated base and fitted a small break tank with an AB air gap. We used Xpress fittings to create a discharge and suction manifold.
To control the high-pressure unit, we built a bespoke panel that controls both pumps via 4 pressure switches. We also fitted volt free contacts for the high and low-pressure faults which allows the panel to link in with the site's BMS system. On top of the above, we installed pressure regulating valves on each pump so we could balance the unit making sure that the discharge pressure can be maintained at 10 bar. To ensure the unit complied with the “Pressure Systems Safety Regulations 2000”, we supplied and fitted two Lowara 16 bar expansion vessels; a 500 litre and small 24 litre buffer vessel.
We fully assembled the unit in our workshop and carried out various tests making sure both pumps cut out to the correct pressures. Once the unit had been commissioned and fully tested, we transported it to site and installed it the same position as the existing unit. We had to convert the supply to 415volt due to the higher-pressure pumps that were fitted.
The project took 2 days with no down time on the chiller as we managed to keep the system topped up via a cold feed loop. All was left in service and the customer was extremely happy.