hot water lockout

[680312]

ive got an ariston microgenus combi boiler.after running hot water the boiler locks out.have to reset boiler then water heats up but after few hours boiler locks out again.have changed both thermostats and descaled heat exchanger also cleaned out fan area.it also takes several attempts to relight boiler.
have no problem with the central heating side.

 

[ChrisR]

after running hot water the boiler locks out

when, ie after how long?
Could be all sorts of things, like the flow switch sticking on. But with no water going through it would overheat and lock out. Then not light until cool.