On 11 Feb 2021 at 23:09:17 GMT, "Clive Arthur"
wrote:

On 11/02/2021 15:50, RJH wrote:
After 3 component failures in the past few months (heat engine, water
pressure
sensor, pressure gauge), it's looking like my Ideal Logic + is on to its
4th.

On starting heat or water and for about 5 minutes, the boiler makes a loud
resonating sound, a bit like a bearing on its very last throes. It's
difficult
to tell where it's coming from with the cover on, centre up. I don't think
it's the fan - the noise stops once the boiler stops firing. Once it settles
down after 5 minutes or so the noise more or less goes, maybe fades in/out
for
a few seconds every so often. Recording clips at:



https://drive.google.com/drive/folde...2u?usp=sharing

(After 5 minutes - noise more or less gone, normal sound)
(First 5 minutes - new noise, boiler from cold, stops after about 5 minutes)

Internet searches tend to suggest gas valve, although this sound can't be
heard outside, and the reports I've read suggest it doesn't stop after a few
minutes. Replacement looks relatively straightforward - 5 minute job. Any
comments please?


At about 10s on 'first five minutes' there's briefly a higher pitched
note changing to a lower pitch. It sounds like a 3:2 ratio, so I'd be
looking for something resonating - it starts off with 1.5 cycles between
it's fixed ends and and settles on 1. It then gets louder and starts
distorting producing a slightly lower fundamental frequency.

Could be a length of pipe, or maybe a panel. Try pressing on various
bits to see if you can damp it. Could be as simple as a loose clamp.

Why does it stop? Expansion? Dunno.

Whatever's causing it does seem to excite various pipes etc - as mentioned
above, I'm going to swap out the fan and see if that helps. A google search
suggests that it's not uncommon to diagnose this sort of fault incorrectly for
this boiler.

--
Cheers, Rob