Getting heating but as soon as hot water is turned on, boiler goes into automatic lockout. Had a problem with water leaking from boiler and low pressure warning light was constanly lit. Changed the bypass valve and fitted new diverter valve too. Problem solved!! (or so i thought!!) no water leaking, bled radiators to get rid of air. Had hot water for approximately 4 hours then same problem started again!! automatic lockout keeps kicking in once hot water has been running for a while. Getting a sore finger from constantly pressing lockout switch!!! Also low pressure light wont go out...HELPPPP....... Could it be the sensing valve???? Any help greatly appreciated..[/u][/b]