Stuart Turner recently launched its own range of Stuart digital pressurisation units. The units – SPU Mini, SPU Midi, and SPU Maxi – can automatically fill, monitor, and maintain pressure within a sealed system. Here, readers can learn how to correctly install the SPU Midi.
The SPU Midi is capable of pressurising systems up to 4.1bar and has a reservoir capacity of 8l. For an easy and versatile installation, the unit can be either wall or floor-mounted – and have the inlet and outlet connections fed from either the left or right side, providing the flexibility needed to install across a wide range of projects.
In our latest installation guide, we’re providing an in-depth step by step to making the most of installing the SPU Midi. Follow the instructions below to ensure your installation is on point.
When unpacking the SPU Midi, check for any damage, and that all parts are included, using the checklist in the instruction guide supplied.
Consider the location of the unit. An ideal location would provide straightforward access to the mains water supply and a suitable drain for the overflow. The SPU Midi can be floor-mounted or wall-hung on a surface of sufficient strength to support the filled weight of the unit. The SPU Midi should also be installed in a dry, frost-free space that has adequate air flow, and the ambient temperature should not drop below 4ºC or rise above 40ºC.
When fitting the SPU Midi, always use the wall mounting plate provided, ensuring it is securely fixed and square – this will secure the unit whether located on the floor or elevated on a wall. Remove the front cover from the SPU Midi – it is attached by a single screw and snap-press fixings – before hanging the unit from the wall plate and securing it with the retaining screw provided.
Next, the side entry fill valve should be fitted with the correct filter and flow restrictor insert supplied with the unit. To select the correct one, firstly determine the mains pressure – if it is between 1 and 4bar fit the coloured insert, if greater than 4bar then fit the white insert.
Full bore isolating valves should be installed on the mains water inlet and pressurised water outlet prior to connecting the cold water mains to the inlet using the flexible hose provided. The connection to the heating/chilling system is made through an additional flexible hose, which is also supplied and secured with a cable tie. Please also note that a drain valve must be fitted prior to the outlet isolating valve. Connect the warning overflow pipe to a suitable drain via a tundish.
Isolate the power before connecting the unit to a suitable electrical supply via a R.C.D. The electrical installation, including supplementary earth bonding, should be completed in accordance with current regulations, and by a qualified person. Next, you will need to wire the alarms and boiler interlock connections.
The SPU Midi unit has output connections for a boiler interlock, protecting it from system low or high pressure conditions. It also has four further alarm outputs which can be programmed on-site to suit individual requirements. In addition, the SPU Midi unit can be supplied with a RS485 interface for BMS system connectivity.
Refit the cover to the unit. The robust plastic cover can be quickly fitted, using snap-lock fixings and a single retaining screw. Switch the power on. The SPU Midi unit is factory preset to allow it to operate in most installations, straight out of the box.
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