Mains pressure hot and cold water systems are great, but only if there is enough water.  If you don’t get enough water from your water main, running one outlet tends to stop another from working, which is rather irritating.  Mains pressure systems are those connected to combination boilers, unvented cylinders (some call these ‘Megaflow’) and heatstores.

Our customer today has a Boilermate III, which is a Gledhill manufactured unit commonly found in newer houses built in the 1990-2009 era.  It uses a heatstore principle;  this is a large vat of permanently heated water from the boiler, which is used as a thermal mass to indirectly heat cold water on demand.  If you have a boiler mate, or one of its cousins, you probably know all about their various trials and tribulations, that could fill another web page.

Our challenge was to improve the flow of water to all outlets through this unit.  We measured the water main and found a static pressure of 0.8bar, and a typical flow rate of just over 10 litres per minute.  Now this isn’t ideal, particularly in a four storey town house.  Not surprisingly, the showers on the upper floors simply don’t work, because there is insufficient water pressure in the Thames Water supply to overcome gravity.

We supplied and fitted a Trentclyde Water Solutions Mainsboost GC450 and Charger pump.

Shaun piping up the Charger pumpset. This is his best side, by the way.


This is a 12 litre per minute pump engine, coupled to a storage accumulator vessel.  The Charger pump has a microprocessor and inbuilt pressure sensors, and can be set to prime the water accumulator to a much higher pressure than that coming from the mains.  Once the accumulator is charged up (like a battery, only using water) the air diaphragm inside pushes large flow rates of water out on demand.

This allows multiple outlets to function simultaneously, and of of course, the upper floors showers work too because of the raised pressure.

Our customer is very happy with the system, which we installed in a weathertight unheated area attached to the building.  The TWS Charger is much quieter than other solutions like breaktanks, doesn’t run every time a tap is opened or a toilet flushed, and keeps the water safe because it is atmospherically sealed.  It is worth noting that the people next door fitted a conventional booster tank solution and you can hear this all over their house, and in our customer’s house!

Finished installation, just waiting for cupboard. I’ve been looking for those cable nippers!

We fitted a small electrical tube heater on a frost thermostat in the cupboard (under construction in the pictures) containing the equipment as protection against the winter weather.

This is the third accumulator job we’ve done in August 2012, if you have a water supply issue please get in touch.  Our customer here has now asked us for a quotation to change out the boiler and the Boilermate III cylinder.