Central heating leaking

[mcgubart]

I have a pressurised mains water heating system. There is a small red tank above the central heating boiler. Attached to it there is a valve with a pressure meter connected (set at 3 bar but reading 2bar). The pressure meter appears to be connected to several pipes in a U configuration. One of these pipes is routed through to the outside of my house. It is this pipe which is constantly dripping water. Is this normal or is there a problem and if so what could it be?

[GeorgeR]

The exterior pipe will leak when the pressure has dropped. The system must be re-pressurised. There should be a car type valve on top of the red cylinder. This needs to be inflated with air. A tyre pump may be suitable. The pressure will drop over time. This is normal, but if it has suddenly happened, there may be a leak. Best to get a plumber.