Worcester Greenstar 24i Junior - Vibration

[ashwales]

This boiler is giving me headache literally the best way to explain it is when the CH is first switched and the boiler is giving its all its spot on, running almost silent!

Give it about 30 minutes or so when all the rads are up to temperature it then starts to slow down and gives out deep dull vibration like a car idling, that's the only way I can explain it, you can feel it in every room in the house when it starts to do it, its a relief when it switches off.

If I set the CH temperature dial to say 4 the second the vibrating starts if I set it to max the boiler speeds up and the vibration stops.

My understating is the pump has a set flow rate, so its always at a constant speed regardless of temperature so can't be that?

Fan running speed does vary from what temperature the boiler is but that runs after the CH turns off and is fine.

What is actually speeding up and down when the CH starts or switches off if its not the pump?

Had the gas flow and pump speed checked last year and the guy said it was spot on, checked the system for air and its all good.

 

[Chuck]

What is actually speeding up and down when the CH starts or switches off if its not the pump?

Your assumption is false. The pump speed varies during normal operation. It's the boiler attempting to control the flow temperature by changing the rate at which water circulates.

There are a several things that might cause the symptoms you are observing and you'll probably need a good heating engineer, preferably one who installs and commissions plenty of of Worcester boilers, to diagnose and fix the problem.

One check you can try yourself is to see if turning the thermostatic valve on a radiator up to maximum modifies or stops the humming noise. If it does the external automatic bypass valve may be missing or set incorrectly.

 

[ashwales]

Your assumption is false. The pump speed varies during normal operation. It's the boiler attempting to control the flow temperature by changing the rate at which water circulates.

There are a several things that might cause the symptoms you are observing and you'll probably need a good heating engineer, preferably one who installs and commissions plenty of of Worcester boilers, to diagnose and fix the problem.

One check you can try yourself is to see if turning the thermostatic valve on a radiator up to maximum modifies or stops the humming noise. If it does the external automatic bypass valve may be missing or set incorrectly.

This was the response from Worcester when I asked them directly

"The pump on the boiler is a fixed speed pump and so would not slow down or speed up based on flow temperature. "

I am thinking its the pump myself, the second I kick the CH off, the pump stops and the vibration stops, thermostatic valves on all the rads are set on the max already.

 

[Chuck]

"The pump on the boiler is a fixed speed pump and so would not slow down or speed up based on flow temperature. ".

I stand corrected; it must be an older model than the one I had in mind.

Are the pipes properly clipped everywhere?

 

[ashwales]

I stand corrected; it must be an older model than the one I had in mind.

Are the pipes properly clipped everywhere?

All clipped in good, no vibration in the pipes, its only from the boiler its self, it only does it when when all the rads are hot without fail.

 

[Gasmk1]

are you sure its not one of your Thermostattic rad valves vibrating

 

[ashwales]

are you sure its not one of your Thermostattic rad valves vibrating

No, to be honest I’ve noticed when using the HW the vibration comes and goes at a certain point just as the HW starts flowing and just as it goes off.

What part is speeding up and slowing down with demand as at a certain speed what ever it is, its causing the vibration.

 

[Gasmk1]

yes it could be a TRV as these sometimes when fitted on wrong side or are failling can vibrate casing a chattering noise

 

[Wetbandit]

I would say if it's just at the boiler it's probably just the case and the Worcester have an awful flimsy tray underneath that doesn't click in anywhere.

 

[AMGasServices]

Has the boiler been serviced regularly?

 

[ashwales]

Has the boiler been serviced regularly?

Was serviced last year

 

[AMGasServices]

Ok i was thinking there could be an issue with a component in the boiler.

 

[waddycall]

Could be a combustion issue. Best to have it looked at.