On 16/02/2018 17:02, Martin Pentreath wrote:
Hi all,

I have a intergas boiler with a developing limescale problem on the domestic hot water side. Taking the heat exchanger out looks to be impractical, so I thought I'd try the alternative technique of circulating descaler through it in situ by connecting up a pump and a bucket of DS3 descaler to the nearby hot and cold washing-machine valves.

I can easily pump cold water through the heat exchanger this way, but as soon as I introduced hot water (by pouring it into the bucket) the pump gave up. To be fair it was the cheapest drill-attached pump I could find:
https://www.amazon.co.uk/Wolfcraft-2.../dp/B0001P1972

Any suggestions for a pump which is up to pumping hot acidic water?

Have you got a spare CH circulator pump?

Failing that, could you use two buckets and a bit of gravity - place one
with the DS3 higher, and let it syphon through to the lower one?

(you would have to manually empty the lower bucket back into the top
again from time to time!)

--
Cheers,

John.

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