Potterton Performa 24 h/w problem even my plumber is stumped

[Setone]

Hi

I've got an problem with my potterton performa 24 combi boiler, which has even got the plumber i use stumped.

the problem is that if you use hot water for say running a bath after the bath is full and the tap is closed the boiler trips the over temperature safety s/w.

C/h works with no problems at all never cuts the over temp s/w.

Called my plumber in to take a look. He has stripped the h/w plate heat exchanger and cleaned, changed both h/w and c/h diaphragms. Problems still remains.



Anyone have any ideas?

 

[matt1e]

Yes you are best off getting a heating/boiler engineer to look at your boiler rather than your plumber,
I take it the boiler is continuing to fire after the tap is closed?
Did he check the DHW flow switch?

Matt

 

[mickyg]

lol stumped. Sticky microswitch, such a puzzler !

 

[gaswizzard]

Anyone have any ideas?

Yea , don't give up the day job.

As Micky ays , difficult one to say the least.

 

[Setone]

Sorry my explanation wasn't to clear, if you run the hot water for a short while , like fill the sink , the boiler doesn't trip out, it only happens when the hot water is used for more then say 5 minutes.

after the hot water tap is closed the burner light goes, i only know if the boiler has tripped out when i got to use the hot water again.