How to re-pressurise your boiler.
As there are so many different makes and models of boilers it’s always advised that you check your instruction manual before starting. These can usually be split into two different methods but it’s recommended that you switch off your boiler before doing either approach!
This is a short length of hose that connects your boiler with your main water supply. Firstly, remove the cap from the isolation valve, this is usually a chrome tap with a black handle. Once this cap is removed, fit the filling loop using an adjustable spanner and tighten it at both ends, make sure you’ve got a good seal before you move onto the next step. Turn the handle on your filling loop so that water starts to flow. An easy way to remember the direction of the valve tap is to imagine a kayak on a narrow stream, it can only flow when it’s pointing in the direction of the pipe. Once the pressure has risen sufficiently you can turn off the valve, remove the loop and restart the boiler.
Internal filling loop:
Lots of boilers are already connected to your water supply so this process is even simpler. Simply turn valves A and B and you should hear the water start flowing into the system, keep an eye on the pressure gauge whilst doing this. When the pressure is correct, close both of these valves and you’re all done.
Internal filling loop (Keyed):
Some internal filling loops require a small plastic key to be inserted into the underside of the boiler, insert the arrow into the grooves next to the unlocked padlock symbol and turn the key towards the locked padlock symbol. When this is done, slowly turn the little nut next to the key anti-clockwise and you should hear water start to flow. Be careful that the nut is fully closed before you remove the key or else water will continue to leak out through this hole.
If you’re not sure which type of boiler you have, then this video provides an overview of the different methods.
What to do if your boiler pressure is too high?
High boiler pressure can be dangerous in extreme cases, but this doesn’t mean it isn’t easily fixable. The easiest approach is going around the radiators in your house and bleeding them, this will release some air and lower the pressure. Once this is done you might need to go back to your boiler and add some more water if the pressure has now dropped below 1 bar.