Worcester Bosch combi boiler, pressure on zero

[lastofthesummer]

Just went to turn on my heating and realised the pressure is on zero. I still have hot water but my house is like a freezer. What would happen if I switch the heating on? Would the boiler blow up?

Where is the pressure guage? Ours is in the airing cupboard for example. It should be about 1.5. You can turn it up and then the boiler should kick in. Have you bled a radiator or something that would make it drop?

You just need to top it up. It’s standard boiler maintenance, there will be instructions in manual or online. Ours is a WB and we just have to open a valve.

Re-pressure it to between 1 and 1.5 bar, if you don’t know how to on your boiler, google is your mate. Our Worcester has a key you put in and turn and then use a nut to open the filling loop.

Don’t run the central heating with no pressure in the system - you will bugger your boiler. Just top it up - there’s a valve - it’s very simple. We have the same model as you. Instructions will be in the manual.

If your pressure has dropped to zero I’d be concerned you might have a leak somewhere. If you have a service contract maybe contact the engineer if you top it up and it drops again. Although pressure can often fluctuate, it shouldn’t drop to zero.

Unless you've never, ever topped it up, then you have a leak or the pressure vessel (or is it called the expansion vessel?) has failed and the water in the system has been ejected out of the little pipe that goes through the wall to outside. In either of these cases you really need to sort the problem. A small leak can be dealt with temporarily by topping refilling the system to 1.5 bar as others have said.

As per the above posters, my question would more be why is the guage at zero? This shouldn’t happen unless you have an escape of water somewhere. Any frozen pipes etc that have burst - I.e have you seen any stains on the ceiling or noticed any patches of moisture? If you try to run the central heating then nothing will happen. The boiler will throw up an error code and refuse to start so you won’t break anything. The filling loop will be to the underside of the boiler - search your model number on the internet for instructions. Fill it to 1 bar and watch carefully. If it loses pressure quickly there is something that needs urgent investigation.

When ours dropped, it was a leaky radiator, that was a 5 min fix fortunately, but if it has dropped there’s probably a leak somewhere. Easiest place to start is by checking all the radiators.