I almost never use the water tap on my ECM Giotto, but I want to do a descale and it seems a lot easier to empty the boiler that way. Also I like things to work. Any quick and easy diagnoses? I took as much apart as I could and there doesn't seem to be much scale or other schmutz anywhere I can see. The hot water valve itself feels fine and though it's hard to tell, it looks like the internal parts are working. What I could see of the copper tubing going to the valve also looks fine and seems clear (I took the smallest, most exposed piece off and it runs clear). Everything else seems to be functioning normally. I had a sticky vacuum breaker valve recently, but it cleared up with a quick cleaning. Thanks, as always, for sharing your expertise!

Hot water taps usually work by having a pipe that is submerged in the water in the steam boiler leading to a valve. Pressure in the boiler forces water out when the valve is opened. If you have boiler pressure and water is not coming out then it pretty much has to be a blocked valve or a blocked pipe. If you're sure the valve is opening, and there's no obstruction in the pipe leading from the valve, then you will need to check the pipe to the boiler. You will need to do this when the boiler is completely cold, (therefore no pressure) and take due care with the copper fittings; it is easy to cross thread them or tighten too much and strip them.