Recently moved to a new property and it has a Worcester 30CDI combi bolier c.5 years old. The combi happily kicks in when taps are being used, however the 2 showers which also run off the mains doesn't or only intermitently. One shower doesn't heat up at all. This is very frustrating only giving cold water. The boiler pressure was very low but we have stablised it to the recommended 1.5-2 bar.