Gas boiler low pressure problem.

MundekStw

Hello.

I have a problem with the boiler. The display shows 0.3 bar. There are no pressure valves under the boiler. Does anyone know how to charge the pressure? I attach photos below. Thank you

embracingLife

Firstly identify the mains water pipe and valve that fills up the central heating system either its among them in the photo in the hot press but I don't think the mains pipe is among the pipes in your hot press photos. Or look around in the rest of the hot press and see any other valve on pipes? Sometimes it's a metallic flexible pipe/hose with a valve on it (called a filling loop) or other times its just another copper pipe with a valve. But there's probably other pipes and valves which bring water from attic tank to the bathroom and the hot press tank/cylinder (the large green tank in left of the photo). So you have to identify which pipe feeds the boiler. Take your time and look around.

I recommend Not to turn any of the red valves in the photos as they are set at the existing positions and turning them will affect the heating system.

Other times the fill valve pipe for the boiler is under the boiler and is accessed behind the cabinet under the boiler but normally there's either a hole at the back of the cabinet or the back of the cabinet is removable to access it. Can you look into the back of the cabinet under the boiler? Do you see any other pipe with a valve.

Once you have identified the fill pipe to the boiler:

On your boiler as you said there's no external pressure gauge, it's only on the display panel it makes it a bit awkward to top up extra water into the system.

Best way in your boiler is to turn on the timeclock for both heating and hot water which causes the motorised valves (the yellow boxes on the pipes) to open and allow free flow of water through all the system pipes. With these valves open you can top up the system by turning on the valve on the mains for about 30 seconds and then turn off the valve. Then go to the boiler display and see what pressure it's at. Usually about 1 bar or in a house 1.5 bar. Do this back and forth until you get the desired pressure, but with the boiler on don't fill it up too far past 1 bar as when the boiler is on and the pump running it alters the pressure artificially higher.

So after you have filled the system for the first time it's best to turn off the time clock and then see what pressure is displayed. But usually the boiler continues to run, mostly it's the pump which is a safety feature and the pump finally stops several minutes later. It's best to wait until the boiler/pump fully stops and the water pressure has returned to normal, then you can see what the new pressure is. If it's below 1 bar do the whole process again until it gets to 1 bar etc.

MundekStw

Thank you for your answer

I understand that I need to turn on the water and radiator heating. Then turn the valve supplying water to the main boiler for 30 seconds?

embracingLife

Yes. Then turn off the water after say 30 or less seconds, try 10 seconds first and go to the boiler and see what pressure it's now at. It's better to do it in short bursts of time as depends on how fast the mains water will go into the boiler.

CramCycle

Typically, not always, there will be a pressure gauge beside the inlet mentioned, so you can see it filling up. Makes it easier and gives you something to look for as you look around.

embracingLife

Well the OP said there's no pressure gauge at the boiler, there's only a pressure level on the display on the boiler. To say that "typically" there's a gauge on the fill valve is not normal. Most of not all filling loops have no gauge on them. It's a bit wishful thinking here to think it's on this system. You can see the pipes under the boiler and in hot press that's there's no way a filling loop with a pressure gauge was fitted.