Redring pumped thermostatic shower

[Smac]

My question is that I have a redring pumped electric thermostatic shower which is installed. In a 2 storey house the pipework to shower is via the roofspace in which cold has separtate supply from storage tank .hot water supply to shower direct from hot water cyl my problem is on a couple of occasions the hot and cold pipework has become airlocked the height of the storage tank to. Shower pipework is approx 300mm why would this pipework become air lock this happens every couple of weeks once I take filters of at shower to flush pipework water supply becomes perfect some solutions would be good

[MAL1N]

More than likely it is the pipe run of the hot supply that is causing the airlock. You will need to check that the pipework is copper, it doesn’t have any sweeping bends and it is in the right position on the vent pipe.