Worcester gas combi boiler making vibrating noise - video inside

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Hi all

Can anyone tell me what’s going on with our boiler? Approx, 8 years old, gets serviced each year, was last serviced in June 2021 with no faults.

We have noticed a vibrating noise coming from the boiler where when you open the a tap for hot water (can be any tap in the house) everything works fine, then when you switch the tap off, a few secs later the boiler makes a loud vibrating noise for a few seconds. It was so random before I couldn’t get a video of it. But for the last few days it’s happening 80% of the time. It only happens after you turn off the hot water tap not during.

lve tried to hold the boiler casing to check for any thing loose but doesn’t help.

Video shows the noise, straight after turning the kitchen hot tap off : https://streamable.com/sq1c0l

the boiler is a cdi 37 combi.

thanks
 
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strange,

i'd have said the fan on cool down, maybe it just vibrates at a certain resonance,

what if you have the heating on, then switch it off, does it do the same noise?
 
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strange,

i'd have said the fan on cool down, maybe it just vibrates at a certain resonance,

what if you have the heating on, then switch it off, does it do the same noise?

Thanks, just switched the heating on, it’s been off for a fair few months, I’ve let it run and get the rads hot, turned heating off and no noise.

I’ve now tried the hot water tap on an off and no vibrating noise as of yet, this morning it was 99% chance the boiler vibrated when turning off the hot water tap.

We will keep an eye on it today.
 
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Sounds like a combustion problem...mixture is incorrect causing flame resonance.
When did it last have a full service...burner gaskets, bearing plate etc and heat exchanger cleanout?
It would have been an expensive job as it takes time and parts are pricey.
 
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Sounds like a combustion problem...mixture is incorrect causing flame resonance.
When did it last have a full service...burner gaskets, bearing plate etc and heat exchanger cleanout?
It would have been an expensive job as it takes time and parts are pricey.

Thanks, it’s never had that as I’ve not had to pay more than the normal annual service costs.

this was the last print out they gave me last month, not sure if helps the diagnosing or the number are specific for each boiler.
 

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It hasnt been getting serviced, it has been getting flue gas analysed, a con by so many companies these days, call worcester and ask for a proper service
 
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If those readings are correct it's running too lean...the CO2 figure should be much higher.
Sounds like the "service" was nothing of the like.
I do a full service (several seals etc) and cleanout every 5 years...
 
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Way to low. Should be around 9.2. That’s not a service that’s just shocking. How someone could leave such a low co2 figure and then print it out! :rolleyes: Would also get the electrode set replaced if it’s got the viewing window, as theses can later cause major heat damage if failed…on contract by any chance?
 
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Looking at printout, I'd say they never put it into service mode to test high and low settings should be 9.7% and 9.1%
Printout signed Steve & Matt
Should be Stan & Ollie
 
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