Kettling - should I switch off?

[AndyI]

Hi all.
Could I impose on your expertise?

My boiler starts to kettle after an hour or two of operation, and I'm working my way through de-crudding the system (de-sludge under way, de-scale to follow) but it's pretty damn cold at the moment, so I'd like to run it quite a lot. (the system is pretty filthy but getting better)

The thing is, I'm worried about letting it kettle at all, and more worried about having the system running while I'm out in case the boiler pipework bursts, or the removed filth exposes a hole, and I come home to disaster. I've flipped the thermostat switch from high to low.

Roughly how worried should I be? Yes, I know it's possible and I'd be taking a risk, but then there's possible like my scoring the winner in an FA Cup final and possible like my toast hitting the floor the wrong side up.

Oh, and I'm closing the feed valve to the expansion tank in case of a burst (checking periodically that it's well filled). Is this completely stupid?

 

[Deleted member 105431]

don't close the feed to the header tank! If you must turn off the mains cold water supply to the tank. Adding X200 may help but it all depends what make/model you have, in most cases the boiler kettling won't do any long term harm.

 

[AndyI]

Wow, quick reply! Thanks!

Sorry, I meant the mains feed to the tank - the one which has a float valve and is used to refill the tank/system. Ashamed to say I didn't know there was another... so... am I OK to close it?

Thanks again.

 

[landyandy]

Where is your expansion tank?

Andy.

 

[AndyI]

Loft, above the boiler (which is in the kitchen).

Oh, and the tap I'm closing is also in the loft, next to and slightly below the tank.

 

[Deleted member 105431]

Wow, quick reply! Thanks!

Sorry, I meant the mains feed to the tank - the one which has a float valve and is used to refill the tank/system. Ashamed to say I didn't know there was another... so... am I OK to close it?

Thanks again.

although it is bad practice alot of ch systems have a gate/isolation valve on the cold feed pipe (typically in the airing cupboard). What you are talking about is turning the cold mains off which is ok. What make/model is the boiler?

 

[AndyI]

It's an ancient Stelrad Group Ideal Elan, serving its last weeks before replacement.

Apologies, got to go out(!), any further advice gratefully received!

 

[Deleted member 105431]

It's an ancient Stelrad Group Ideal Elan, serving its last weeks before replacement.

Apologies, got to go out(!), any further advice gratefully received!

these are low water content boilers and prone to noise at the best of times. Have you checked the pump is working ok?

 

[AndyI]

Well, the pump is humming very quietly to itself and hums a different note for each of the speed settings, so I think it's in good nick. Not quite sure how to be certain though. I replaced it quite a while ago when the old one died - now that was a serious kettle!

Thanks guys - will be less paranoid about the kettling, but will probably shut off the mains when appropriate.

 

[hect]

Kettling on these is down to poor circulation, whats ya temp diffs???