Loss of hot water

These sure were not out for long. The bright red button is a pressure release valve which could be faulty hence allowing water to bypass out of the system and not having hot water. Try strapping a bag around the pipe that goes outside and see if it fills with water. To top up your system look on the pipes just below the boiler. There should be a cold filling loop or a connection for one. If not get one from a plumber and ask them how to fill system up, its straight forward enough and your problem should be fixed with this info

let me know if you have further questions

my best to you

Robert, i'm sorry to say but the AAV's are machined parts and the seal should not have been broken by removing the cap. The floats are set perfectly and you would have been easier replacing the whole vent. You could have isolated all the pipes under the boiler and just drained the boiler down by releasing any pressure by the pressure release valve. You may need to buy another AAV and start again.

Hello Mark
First of all turn on a hot water tap and keep it running whilst you check to see if your boiler is firing up, if it is not then try to restart it, you should hear the flame if its running, turn your tap off then just stand by the boiler for a few minutes to see if the pressure gauge starts to rise, if it doesn't rise you will never get any hot water, you will have to add some pressure to about 1 and a half on the dial, to do that is simply turn on the water valve in the bottom of your boiler and watch your pressure gauge rise to about 1 and a half then firmly turn it off again, it looks like a small tap like the one at the back of your washing machine pipe, it's ok you will hear the water rushing in, now with your gauge at about 1 and a half and your boiler running your water will get hot

try check in the water pressure on the boiler should be on 1.5 bar

Hi - hope someone can help. I have a VOKERA EXCEL 80SP combi boiler and been without hot water/central heating for two days. The pilot light is on, the fan is on, but boiler not triggering once the hot water tap is turned on.
Hopefully someone come to look at it today but hoping for some advice. Anyone else had this problem?
Thank you.

I have a similar problem with this boiler. When CH on, boiler overpressurises, (check relief valve outlet) You will then lose water from the CH loop and will have to repressurise when the CH loop cools. The problem is most likely caused by a loss of air from the expansion tank, which will need re-charged. This is not a big job as it has a standard tyre type valve connection but needs an accurate pressure gauge. Probably best left for plumber.

there is a zoneing valve thats suppose to be in the line to keep this from happening, might even have a check valve either way which ever one you have is bad and should be changed with a new one

if there is no signs of any leaks try topping up the pressure from the fill loop and reset the boiler

You boiler is more than likely low on water. There is normally an automatic water feed. When you bleed a system the pressure naturally drops but is compensated by additional water feed into system. You have a problem in the pressure make-up water feed to your system.