Glow Worm Economy Plus 50BF noise issue

Johnhowell

Dear All,


We have the above 24 year old Glow Worm boiler in our recently purchased home. It was serviced just before Christmas 2015 and was nice and quiet - along with a new Altech pump fitted.


Since then it has gradually become more noisy during burning. The sound is like a kettle working toward boiling - "fizzing" sound. The system has been chemically gravity flushed several times and new inhibitor, noise reducer added. A magnetic filter was also fitted which traps very little each time I look.


Is this noise a symptom of a sensor fault? Is the boiler "overheating", over gassing? During the service the plumber vacuumed the burn chamber - was a sensor damaged or the burner grills cleared of so much debris that the grillage is too open (like an old cooker I had once)?


I hope someone can give me some pointers before calling the plumber in.


Many thanks,
John

southcoastrgi

Where is the knob pointing on your pump ?

Johnhowell

The pump is set on 2 out of the three settings. If it is set to one, the fizzing increasing in loudness, but doesn't reduce much if set on three. When set on three the pump groan through the pipework is more intrusive.


Cheers,
John

*j*

Have you tried a boiler silencer in the header tank? It may take a few days to be fully effective....http://www.screwfix.com/p/no-nonsense-central-heating-noise-reducer-500ml/82634

Toolstation also do one...http://www.toolstation.com/shop/Heating/d230/Central+Heating+Additives/sd3235/Corgi+Boiler+Noise+Silencer/p33333

Johnhowell

*j*
Yes, noise reducer has been added.


When I added noise reducer (Sentinel X200), inhibitor (X100) last year the boiler went very quiet - it was bliss. As I said in first post, since the service and pump (and pump valves) change the plumber added some additional inhibitor - didn't see what brand. The noise came back. Some one at work suggested the different chemicals may have caused foaming so I did a complete flush. Drain down, add cleaner X800 for a couple of weeks, then drain down, flush, several cycles (as recommended in the British Standard), refill with fresh water and X100, X200 added - took all day! But the noise hasn't gone away :-(


So is it something in the old boiler not working?


Cheers,
John

southcoastrgi

X800 for a couple of weeks :eek:
That's really designed to be used with a powerflush machine plus you may have seen a clue on the bottle ie fast acting cleaner

Johnhowell

southcoastrgi wrote: »

X800 for a couple of weeks :eek:
That's really designed to be used with a powerflush machine plus you may have seen a clue on the bottle ie fast acting cleaner

Sorry, mistyped the X number without checking. I used the non-power flush cleaner - X400? Too many Xs!


John

Johnhowell

Any further advice, pointers, etc. welcomed...


Or do I bite the bullet and get a new boiler installed?


Regards,
John

chrisw

It's called Kettling. I had it in my Glow worm boiler and when I looked into it, I was told it was caused either by furring up in the boiler giving the bubbles something to form on or by the water passing too slowly through the boiler.

On mine, there is a bypass pipe with a gate valve running from after the pump but before the zone valve to somewhere else I can't see, presumably the boiler. I opened this valve a touch and the noise stopped, I guess it allowed better flow through the boiler.

As you may guess, I'm not an expert but hope that helps.

Johnhowell

Many thanks Chris,


The heat exchange has been removed and is clean - the chap was very surprised how clean it was considering its age. The slowness of flow has already been mentioned. I will look in the airing cupboard and check valves.


Cheers,
John

Johnhowell

So, I have looked at the valves in the airing cupboard. Not many around the pump and port valve. I put a spanner on the pump valves and seem firmly fully open.


I am at a loss...
:-(