my performa 28 ignites when using the upstairs hot water but not down stairs. It also switches off if you run a cold tap upstairs aswell. I think it must be a pressure sensor as the pressure reading are good. Is there a sensor on the hot water side???

Lee Goodall, February 2012

Yes you have a flow sensor, to tell the boiler you want hw. different units use different type of switch, some a microswitch moved by a diaphram when hw turned on, you would be able to see actuating arm move, if it moves, switch fault, if not move diaphram fault. Others use different types of sensor, try manufacture web site, most have pdf downloads of manual, which will give you part number to get one

SD, February 2012