Question from Richard Foot, via email:
My Trianco AZTEC electric boiler (EB 897) includes a Zimlet cylinder (0036) in the installation. The system supplies five radiators and domestic hot water. The mixer shower is gravity fed but the pressure is very poor. There is a hot water cylinder and the Zimlet tank connected in the system, which I am trying to establish the purpose of. Should it assist the water pressure for the shower or will I have to have pumps fitted in the gravity fed pipes to improve the pressure?
Answer from Russell Liversidge from TR Engineering:
The Zimlet cylinder I suspect is the expansion vessel for either the heating system or possibly the expansion vessel for the unvented domestic hot water system. Both take up the expansion of the heated water. The shower will be effected by either the incoming mains water pressure and the pressure reducing valve if an unvented cylinder is fitted or the height of the cold feed tank which supplies water to a vented domestic hot water cylinder. Shower pumps can help with flow rates at the shower head if the cylinder is vented and the height of the cold feed tank is insufficient.