Kettling and radiators cooler at the bottom

[spiro1263]

Hello,

I'm after some advice please.

We have a Worcester 28Si II combi boiler in our airing cupboard that was installed 11 years ago and supplies 10 radiators around the house.

Last year I noticed some kettling noises in the boiler that were vibrating the main bedroom radiator and waking us up at 2am etc. I added some X200 noise reducer to the system (and X100 while I was at it) and refitted the noisy radiator as one of its brackets was loose. This cured the problem and we could sleep uninterrupted again!

A few weeks ago I noticed kettling noises again in the boiler. Within a couple of weeks (and before I'd had chance to add any more X200) this suddenly became much louder to a level where it would wake the whole house up if the heating comes on from cold which isn't ideal with a baby and a 4 year old!!

What I should add is that the kettling noises last for approximately five minutes when the central heating switches on from cold (or luke warm) and stop once the system has heated up a bit.

Anyway, I added another 1 litre bottle of X200 noise reducer last week but this hasn't made any difference. So yesterday afternoon I added some X800 Jetflo Ultimate Cleaner. It's early days, but it still doesn't seem to have made any difference.

I added the X800 by isolating then draining a sufficient amount of system water out of a downstairs radiator. I then poured in the X800, then opened the isolator valves with the bleed valve open until any air left in had escaped.

To make matters worse the lockshield valve on the radiator I added the X800 to is now leaking. Despite this, I left the valve wide open for a few hours to give the X800 chance to circulate but I've now had to close so it's almost completely shut to stop it leaking.

I've also noticed that some of the radiators downstairs including the one that has leaking lockshield are noticeably cooler at the bottom than the top. The rad with the leaking lockshield was still noticeably cooler at the bottom when the lockshield was wide open.

So I'm a bit stuck and I'm after some advice. I'm now thinking it's a sludge problem but I'm also wondering if there's a problem with the pump which would possibly explain both the kettling and the downstairs rads being cooler at the bottom.

Any advice?

Thanks

Mike

 

[Madrab]

When venting the rads, is the water dark or black?

Where is the lockshield leaking from, the gland on the top?

The temp characteristics of the rads could point towards it being sludged up, the sludge could also be restricting flow into/through the primary heat exchanger. Are you in a hard water area?

 

[spiro1263]

Thanks for your reply.

Here's a pic of a sample I drained via the drain cock of the radiator with the leaking lockshield. The colour is the same if I open the bleed vent.

//media.diynot.com/50000_49637_89106_61553259_thumb.jpg

As you can see it is is a pale yellow colour - a bit like a sample of a different kind

Yes, the lockshield is leaking from the gland at the top.

I understand the water in our area is "somewhere in the middle" between hard and soft.

Thanks,

Mike

 

[spiro1263]

What I forgot to say is that the colour of the sample drained from the radiator draincock looks just like the X800. As the same radiator is also cool at the bottom, is it possible that a lot of the X800 is sat in the bottom of the radiator or will it have dispersed around the system by now?

 

[spiro1263]

Hello,

Does anyone else have any further suggestions on this?

Thanks,

Mike