Having problems with this boiler with the hot water running for about 5 mins it locks out .then after a while I try it again it works for another 5- 10 min then locks out again CH is ok , I’ve done usual checks the gas valves ok and the amount of pressure is there is fine ,and ohms is about right on the gas valve ,also checked the plastic gas pipe above gas valve there common to break that’s ok ,but I think it is more of a problem over heating as I did here hissing from the cell cylinder so just wondering could it be scaled up. I contacted WB they said it’s the ignition probes but can’t see that to be honest I’ll changed the probes as there easy enough to eliminate that any ideas please