The flat that we rent out has a Baxi Mermuda (601?) back boiler that's
making "kettling" sounds. The system is pumped with a 3 way valve (Y plan?).
I guess the boiler's getting a bit ancient but it passes the safety tests
OK.

I'll try turning up the pump speed but is the problem likely to be a scale
build up? If so, what's the best additive to try to descale it? (Because the
rads have vent keys at the back (!!!) I'll need to add anything via the
header tank).

Dave S

On Wed, 22 Oct 2003 11:02:51 +0100, "Dave"
wrote:

The flat that we rent out has a Baxi Mermuda (601?) back boiler that's
making "kettling" sounds. The system is pumped with a 3 way valve (Y plan?).
I guess the boiler's getting a bit ancient but it passes the safety tests
OK.

I'll try turning up the pump speed but is the problem likely to be a scale
build up? If so, what's the best additive to try to descale it? (Because the
rads have vent keys at the back (!!!) I'll need to add anything via the
header tank).

More likely to be sludge, because the heating water is (or should be)
a closed system. Once the initial calcium and magnesium salts in the
water are deposited, that should be it.

Try draining and flushing the system at the boiler. There should be
a drain cock next to it.
After that, you could refill and run a flushing agent through the
system for a few days. Flush with clean water and then add inhibitor.
There are also system quietening additives, but the system should be
cleaned first.








..andy

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Dave.
Try checking the position of all valves and drain-off as bad positioning can
lead to kettling