Potterton performa 28i, no hotwater, died over last 3 days

[lostkiwi]

Hi, I have spent last few hours reading to try and find a solution but to no avail.
Over last few days problems with my hot water have occurred.
When hot water did not worked I increased the pressure by .5 bar then it would work again. This went fine until I got to around 2.5 bar where I didn't want to increase anymore.

Also I found that if I turned the tap on full or another tap as well hot water would come but now not anymore.

When I turn the hot tap on the switch goes and the boiler starts but there is no ignition. The next thing that happens is I get a warning light which indicates low pressure or the pump fault.

The central heating used to still work well, even when the hot water had stopped working. Now though when I try the central heating the ignition light starts, temperature goes up but at around 70 degrees it now gives the same error as the hot water(low pressure or pump fault)

The pre heating function still works fine.

This all happened 3 weeks ago but then it seemed to fix itself.

Any ideas would be much appreciated?

 

[baxpoti]

Auto air vent is not doing its job, could be closed or contaminated.

 

[lostkiwi]

Thanks for your reply baxpoti.

Do you mean the Auto air vent on the pump?
I don't see one on the Expansion vessel.

If it is the pump AAV you mean then it has a plastic top to it but it all seems quite corroded and Im afraid Id break it if I try to turn it.

I took the cover screw of the front of the pump to let any air out of there and to ensure the pump was turning. It spins easily.

When I turn the hot tap on I can hear the pump spinning.
The boiler just doesn't ignite but it does for the preheating function no problem.

Any other ideas or should I try the AAV?

 

[lostkiwi]

The AAV has started leaking so even though I haven't managed to remove the screw, loosening it seems to have done some good.

Am I right to assume that if its leaking water then there is no air in it(tiny wee drip coming out of it)?

That being said we still have no hot water.
Any more ideas?