Vibration Noise From Boiler

[DBeeny]

My system is a sealed combi Vokera boiler system fitted 1983. Worked o.k.
I have recently installed TRV to all radiators except one. I have also had to move the 22m rad supply pipes to allow removal of chimney breast.Pump works fine as do all rads. problem is after the system has heated up from time to time get loud vibraton from boiler only last a couple of seconds. Can you throw any light on problem. Would fitting a auto bypass valve help? Thanks Del

 

[kevplumb]

might try a cleanser and flush again

 

[DBeeny]

Can you recomend a suitable cleaner for my system, all my rads are aliminum.

Thanks Del

 

[kevplumb]

sentinel x 300

 

[DBeeny]

Have had the descaler/cleaner in system for 2 days now still getting kettling air noise from boiler. Whilst watching boiler for noise to occur noticed pressure gauge rise to almost 20m when running(is this o.k?) boiler would then cut out when reaching stat temp the noise then seems to start. Noise sounds like air in boiler, then the pressure gauge would then drop back down to about 12m. System would then start up again when stat cuts back in and the cycle starts all over again.

Just a point after filling the system to flush it out I had all radiators valves fully open. I ran the system for a couple of hours like this to get the flush working did not get any noise from boiler? It was after I started to reduce the flow on the rads and turn down TRV's to a normal room settings, noise then returned to boiler.

Thanks Del

 

[laxhill]

This sounds to be exactly what I currently have. Noise seems to appear at random, lasts for a second or two. Case sometimes vibrates with the noise. Seems to happen when boiler working "hard". Can happen 6 times in half an hour and then not for a couple of hours etc. Only on central heating. Noise makes exactly same sound each time although loudness varies. Worcester boiler. Under 2 years old. Had pump replaced and other bits. I suspect expansion vessel might be the culprit as this was replaced on Saturday and touch wood (and everything else) it has been quiet ever since. The new vessel is different to the old one in that it has a bleed valve on it. The "old" one didn't. Trapped air causing problem??? I'm totally non tech on boilers so just passing all this on in case it helps.
Keith

 

[kevplumb]

have you got trvs on every rad ?


laxhill you dont get a bleed point on an expansion vessel
its either a charge valve
or its not the expansion vessel

 

[laxhill]

Re bleed valve - I might not be describing it correctly. An air vent? It's on the top of the vessel and is a small cylinder with a small black cap on it. The charger is half way down on the side. It is most certainly an expansion vessel.

 

[laxhill]

ps trvs on every rad except one

 

[kevplumb]

repeat after me
you do not have an air vent or bleed valve of any description on an expansion vessel
you do heve a charging valve and a connection to the system

 

[laxhill]

Repeat after me - it is an expansion vessel -
http://www.worcester-bosch.co.uk/index.php?fuseaction=product.detail&con_id=5070&detail_id=7604


to make it easy it's the red thing on the left numbered 7. The updated model has an air vent on it on the top. I know because I've got one. If you are truly interested contact Worcester who I am sure will put you right. Me - I was only trying to help the original poster not get involved in an argument with someone who apparently knows even less than I do but then I'm not a plumber

 

[kevplumb]

know what it looks like fitted a 35 he 3 weeks ago
it didnt have a vent on the vessel

 

[noodlz]

Since you've recently installed trv's and problem since then, checked they've been put on right way round ?

 

[laxhill]

We agree it's an expansion vessel then
Worcester engineer fitted the new one on Saturday. "It's an updated model" he said. I can only assume they have had some sort of problem with air being trapped or else why include a vent on it? My boiler has been plagued with this 1-2 sec rumble noise ever since it was installed 2 years ago. Of course it's never done it when the engineer has been here. This is the longest it has gone without making a noise so fingers crossed replacing the expansion vessel has finally cured it. But from reading the original posters post his problem sounded identical to mine. Unless he is watching the thread it might be wasted effort though.
PS the vent looks like this if it helps
http://www.edirectory.co.uk/pf/static/880/mi/954/p1631954.html

 

[laxhill]

Thanks Noodlz - fault not tied to trv's time wise but they've been checked anyway. I'm pinning my hopes on the expansion vessel