Potterton Combi Boiler stars in 'No Hot Water Upstairs' saga

[scarybex]

I am hoping someone can advise me..I have had one cold shower too many

I have a Potterton Performa 28i and for some reason the flame will not ignite if I run either the sink tap or the shower upstairs. It works fine downstairs, although sometimes is a bit slow to catch. The heating works perfectly on both floors. The pressure is fine. It's been cleaned out.

I should mention, the problem came on progressivly, it wasn't a sudden thing. Also when a boiler engineer came the first time he tried it he got hot water upstairs fine (typical!)

Any clues? Do I have a crappy make?

 

[Slugbabydotcom]

I'm not too familiar with these but after a look at the MI's I see theres a device referred to as a 'Flow sensor with filter'.
If this filter became blocked then the situation you describe could occur.

 

[petit_pablo]

Check the hw diaphragm first. It's located next the gas valve rather than on the diverter.

 

[scarybex]

Apparently, according to to potterton it's unlikely to be the flow sensor filter, I shall try the diaphragm!