how to add water to hot water boiler for heating?
the boiler should fill itself, if it doesn't you need to have it checked.
Can you please elaborate on your question as its a little vague. Are you referring to a heating boiler?A combi boiler, a make/model may help.
There should be a tap somewhere on the water pipe that goes into the boiler. Try turning it on. But be careful. There should be a pressure gauge and you can't go over a certain pressure. I think you should call in a plumber and get him to do it and also show you what to do in future. You can't mess around with these.
In Europe many boilers have the pressure reducer built in to the boiler and have a braided hose to connect to the water line to fill it. Do not run the pump or boiler until it is filled. You will have to bleed the air at the high points, such as the radiators. If air is sucked into the air bleeds when you open them, you may need to run the pump to bleed them. When the pump is running, check the pressure and bleed them again, you may have to add more water to make up for lost air. Close the water fill valve before you reach 20-30 psi or you may cause the relief to open. If the relief opens and then leaks after closing, you will need to replace it, as it is defective. If you have too much pressure you can open the drain valve to remove some water.
