As part of general ongoing winter maintenance we had our gas hot water boiler serviced and de-calcified. A couple of years ago we had a problem with the hot water boiler scaling up with calcium. We live in a hard water area and previously the hot water flow started to slow down over a period of a few weeks. It turned out to be scale build-up in the internal pipework, which I fixed by hand by poking down the tubes with wire etc. The same problem started re-occurring, so this time we decided to get a specialist in to clean the boiler.
Basically, they filled the hot water tank with hydrochloric acid, and used some sort of re-circulating pump to disolve the scale and flush the tank of all the calcium build-up. The whole process looked really scary with masks, big rubber gloves and vats of acid.
Anyway, boiler serviced and hopefully in tip-top condition for the following season.
