Glow Worm Fuelsaver MK11 30BR banging and clunking

[AlexanderN]

Hi Guys,

I moved into my house about 2 months ago, the boiler was working fine when i moved in providing HW and CH. whilst i've been working on the house i've had the boiler turned off (with pilot light on) now i've come to turn it back on it clunks and bangs very loud! the boiler then seems to turn off for a minute then it all starts again. i'm managing to get "warm" water out of the tap but that's all.

I'm guessing the boiler was fitted when the house was new in 1991

Has anybody got any ideas what it could be and what i should check?

Thanks

Alex

 

[Whitespirit66]

Sounds like pump. Have a look at this post.

//www.diynot.com/forums/plumbing/glow-worm-24hxi-cycling-and-banging-help-please.325469/

 

[gas112]

Sounds like your pump is stuck hold pump and give it a sharp tap with a hammer .
Impellor can manually be turned on most pumps if this fails , what make of pump do you have

 

[AlexanderN]

Thank you so much! a sharp knock with a hammer did the trick! it's all running smoothly and my pregnant partner can have a bath!

It's a grundfos selectric pump btw.

Is this a sign that my system needs a flush?

Thanks

Alex

 

[45yearsagasman]

It's a sign that you need a new pump.

 

[misterdubya]

Probably not. Pumps are like women, if you dont use them, they sieze up. They also do benefit from fairy liquid - pumps of course

You will need a new pump eventaully though.

 

[Whitespirit66]

Pumps are like women,

Yes, some whine, others just need a good bang.

Pumps and women. Many similarities.

 

[misterdubya]

In most cases they whine until they're banged hard - especially if they have not been used for a while.

 

[AlexanderN]

I see!

Thanks a lot, i'll look into new pumps then!

Alex

 

[gas112]

Alex it is a very common thing that happens to pumps when they have not been used for months which is why a lot of modern boilers turn the pump on every 24 hours if they have not been used .

It is neither a sign that your pump needs changing or the system needs flushing.

 

[45yearsagasman]

If it keeps running then you have been lucky and it may be ok for a while.
In my experience, once a pump plays up like yours then it will happen again.
A pump in good order will cope with being shut down for weeks, and will start again when required.

 

[gas112]

Anyone claiming to be a 45 yeargasman would have years of experience of attending gravity systems usually around october when people turned the heating back on and low and behold the pumps would be jammed.

Would get a couple everyday for the whole month ,start them up with a thump or twist of the impellor and they would work perfectly for years afterwards.

Thats why people where always advised to switch the heating on once a week.
And why it is now built into boiler why else would manufacturers go to this trouble

But then again a 5 minute repair doesn't generate the same income as a pump change does it

 

[45yearsagasman]

We are not talking about a gravity system here! It's a fully pumped system and as such the pump will have had a lot more use. I agree about the October turn ons, but that is usually down to sludge build up and not wear and tear, oh and thanks for the patronising comments about my 45 years experience. We are all on here to give of our experience.

 

[gas112]

So you agree with there being no problem with starting a pump that has jammed on a gravity system but think that 3 months of around half hour a day will make a lot of difference on a fully pumped system.


Can you answer my comment why would manufacturers build it into boilers if it was not a common fault they are trying to eliminate and modern boilers are all fully pumped

Personally i would never ever change a pump first time for jamming through inactivity IF it came back in a short period of time then yes i would then change it.

 

[45yearsagasman]

I have clearly touched a nerve (no intent) but have given advice based on my experience and don't have to justify myself to you or anyone.
The gravity system issue is going completely off topic. You know, or should do, that to make a correct diagnosis of this particular fault, you need to be on site to judge whether the pump needs replacing.
I could say a lot more about pumps on gravity systems, usually on the return and working at lower temps and lasting 20+ years but I won't.