Central heating boiler losing pressure, what to do?

[Robby]

I think of the combi/vented comparison as similar to the comparison between a modern car engine and an old truck one.

The modern system will give reliable and efficient operation if you service it regularly - in the case of a combi this means keeping it bled, keeping the inhibitor strength up, and occasionally flushing the system through (which I do with mains pressure every couple of years).
Once it starts to get silted up though, you're fucked.
- The plate heat exchanger gets clogged, which slows down the flow.
- This lets the primary heat exchanger run slow, boil, and knacker itself.
- When the system starts to silt up and rust more internally, you get more air in the system. This makes the pressure fluctuate more, which puts more pressure on the expansion vessel, and kills it.

[Rogerborg]

[Ribenapigeon]

Engineer maneged to repressurise the expansion vessel. He said that the diaphragm can leak water round the seal over a long period so the diaphragm hasn't actually gone. He also recommended the system get flushed and showed me how i could do it myself. He also said as the boilers nearly ten yeats old i should shop around for some insurance.

[Robby]

Boiler insurance usually includes an annual service too. I pay about a a tenner a month on my 10 year old boiler. It's worth having.

[almostthere]

put inhibitor in the system stops the stinky air from building due to corrosion
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