Lots of Air Coming Out Of Hot Taps

[Lee Parry]

Hi, the hot taps on all 3 floors in our house seem to have a lot of air coming out of them, and because the water is so hot when it splutters out it often coughs out wads of steaming water that are quite dangerous.

We have a gas boiler and tank in the kitchen on the ground floor. The air problem seems worse the further up the house you go, but it happens in the kitchen too. The water pressure seems good on all taps.

I notice that one of the pipes coming out of the tank has a gap in it and a plastic skirt, it looks as if it might be some way of getting air out?

Also pretty much once a day the actual boiler doesn't spark up, the light flashes and we have to press the reset button.

Page of pics of the boiler and mentioned 'air' pipe?
http://www.pixelhospital.com/boiler/

Anyone have any ideas? Or is this something we'll need to get a plumber for?

Thanks for any ideas!

[stanleyman]

You have a mains unvented hot water system and it is unusual for them to overheat as they have so many safety features. Check the hot water thermostat is set at 60C low down on the cylinder, they are easily disturbed (put some tape over the knob) and that the immersion is switched off. The plastic tundish is a visual indicator of water passing the pressure or temperature safety valves.

I would get it all checked over as the unvented cylinder may not be installed correctly (a licence is needed to install) and can be dangerous. System pressure is a bit low should be about 1 bar cold, more with three floors and if the cylinder is downstairs. Very useful pics wish more people would do that.