We have a problem with a Halstead Quattro combi which works OK on DHW. When we use it for heating, as soon as you start it, the pressure builds up to 3 bars in about 10 minutes and water starts to leak outide through the safety valve. Then the pressure will continue to drop quickly until it reaches zero, at which time the boiler stops working. When we re-top the pressure back to 1 bar, the same as above happens again. We had a new safety valve installed last week with no improvment. We were told it could be the diverter valve. If anyone has any ideas, please help
