Has this CH boiler had it?

[jal]

Apologia: I am a rank amateur at CH, compared to the regulars on here. I tremble to place this before you.

I've got a Myson Apollo CH boiler which is -- to my astonishment -- 15 years old (I still consider it brand new, probably because I'm still smarting from the cost of installation).

We had endless trouble with it (and the whole system) when first installed, but it finally settled down to just being noisy at times, which we have put up with, along with regular bleeding of the rads.

This last winter the boiler noise got worse: noisy heating of the system generally, and spasmodic bouts of grumbling, rumbling, occasionally roaring [sic] and even the odd bout of shrieking [*sic*]. All such episodes last for about 30 seconds, then stop when the boiler reaches its max temp and cuts out, the cycle restarting a few minutes later. We often have a period (of days) of just normal noisiness, with no alarming roars, shrieks, etc.

This winter I cleaned out the boiler as per the normal routine done by a plumber (i.e. a brush and vacuum cleaner). I also added a descaler to the system. We don't get shrieks at the moment, but it still does get bloody noisy regularly.

The heat exchanger really does look pretty grotty from the outside.

Is there any way to clean the heat exchanger (I'm pretty sure that that's what causing the noise). Or do you think it's time to start getting quotations from heating engineers for a whole new system?

John

[Owain]

Have you tried properly cleaning out all the rads and pipework and then adding a corrosion inhibitor?

"Regular" bleeding of rads should be approx annually.

Owain

[Ed Sirett]

If that.

There is an underlying problem here. Either air is being drawn down or there is corrosion happening. A problem that I have seen once with this boiler is that the pump overrun thermostat not only fails but sometimes stops the pump at certain temps. Even after a thorough clean out of the entire primary pipework, addressing all other issues and adding inhibitor it may well be sometime before the noise stops.

If I were asked to "do something" about this system I would check and correct the possible problems and then add inhibitor and noise reducer. Any thing more is, frankly, not justified on this age of system.

[jal]

Thanks Ed, and Owain, for your advice. Once more unto the breach, I think.

john

[Dave Plowman (News)]

I don't agree. It should be *never* after the initial work. If air is getting in water is getting out. Or, of course, some form of gas is being produced internally due to corrosion.