The Aqualisa Siren SL Shower Mixer states a minimum pressure range from 1 metre head so you would think it would be suitable for a single shower power booster boost.
In a property in Norfolk I fitted a single SP2 to improve 2 showers which despite a raised cold water tank to give 2 metres head (and 28mm feed pipes to the showers) was giving 4 litres a minute
Having fitted a shower power booster SP2 to the hot which increased the pressure to 0.5 bars (5 metres head), the flow only when up 10%.
Further investigation identified 5 filters in the shower which were 50% blocked with plumbers putty (with 2 filters one on top of the other in just one hot feed) – removing these filters increased the flow a further 10% but THE SHOWER POWER BOOSTER DOUBLED THE PRESSURE SO I HAD EXPECTED 50% OR MORE MUCH MORE!
Fortionately the customer has booklet which came with the Aqualisa Siren SL and in bold reinforced text in the booklet it said ‘Siren products are not suitable for mixed supply systems eg gravity hot and mains cold’.
This was the vital clue I needed. Was the shower mixer unlike many mixers which can balance differential pressures of between 4 or even 5 to 1? Had Siren sacrificed its ability to mix differential pressures to aid higher flow rates?
Its very easy to upgrade a SP2 with a second slave pump (£45). The slave pump runs from the same transformer and uses the same flow switch and simply plugs into the SP2 so every time the hot is booster the cold is booster at the same time.
WITH UPGRADING TO TWO PUMPS THE FLOW INCREASED FROM 4 LITRES A MINITE TO 8 LITRES A MINUTE = ONE VERY HAPPY CUSTOMER WITH 2 PERFECT SHOWER = ONE VERY HAPPY INVENTOR OF THE SHOWER POWER BOOSTER.