Oil Combi making grinding noise

[Matt789]

Hi wondering if anyone can give a diagnosis on the latest trouble with my boiler

After draining the central heating to add new radiators and re-work some piping on flushing out and refilling, my boiler is making a now familiar grinding noise and very occasionally what i think could be described as kettling

On initially refilling the CH loop there wasn't any noise which would lead you to think its now scaling up because there's no treatment in there, but there has been a suggestion before that the bearings could be going in the pump or the pump in general is knackered, could anyone say which is most likely from the symptoms?

Thanks very much to anyone with suggestions

 

[greemyamochop]

Grinding very different to kettling

Kettling will be coming from the main heat exchanger which could be air especially after youve drained and filled back up again

Is the grinding noise coming from the oil burner and not the water pump?

Oil pumps are very noisy when they go

 

[Matt789]

ta for reply greemyamochop i'll just see if i can tell but i was literally off to screwfix this second to get some fernox f2 (silencer) before they closed, will this be a wasted effort if its the pump or would this generally help?

 

[Matt789]

finding it really hard to tell but i would say its either the burner or the oil pump

 

[Boilerman2]

Is it a Riello RDB Burner?? if so does the noise pick up after about 12 seconds (when the flame actually lights up?) if so undoubetly the oil pump (a known fault!!!) Is the boiler a Grant Vortex Combi ? I ask as these can be difficult to vent after draining down due to non return valves this would cause the water pumps to grind, Grant supply a little key to fit the vent plugs on the Two Non-return valves so you can release the air, they suggesat filling the boiler to 2-00 Bar while you do this, and lowering back to 1-00 bar once vented

 

[Matt789]

looking at other posts it seems like the fan is also a possibility, its a worcester bosch heatslave 15/19 over 10 years old, the noise is there from starting it up, before you hear it fire then quite often it gradually falls away after 10 mins or so - only to come back with a vengeance

 

[Burnerman]

As the motor turns the fan and the oil pump, its worth popping the burner out, and opening it up to see if the fan is loose or catching on something.
John

 

[oilhead]

Are you sure you have sufficient water in the boiler? The grinding noise could be the pump, and if you are not circulating water, then the static water will boil, or kettle.
Did you bleed the circulator when refilling?

 

[Matt789]

okay sounds interesting..there are two bleed valves on top of the boiler one which is definitely related to hot water and is on top of a feed pipe and the other on top of a fairly big cast metal box, both of which i bled - is that okay ?

 

[Matt789]

oh and i bled the water pump from the screw at the front

 

[Matt789]

As the motor turns the fan and the oil pump, its worth popping the burner out, and opening it up to see if the fan is loose or catching on something.
John

i only just saw your post sounds like a damn fine idea but the only manual i could find for it doesn't give any maintenance info so i don't know how

 

[Boilerman2]

Now you have named and shamed your boiler, I can give more specific advice - Bentone B9 Burner motor noisy, possibly due to the oil pump leaking oil into the bearings, so check motor & pump on the burner, and replace parts as required

 

[Matt789]

Ah yes you are indeed correct it is a B9

I had similar problems about 7 months ago and called someone out, sods law was on the day they were due to arrive the noise went away. I asked if he could open up the pump anyway to have a look but after having done so he more or less drew a blank saying there were no big signs and as the noise went away that didn't leave him anything to go by

Does that sound fair? or is there noticeable wear of the bearings before they go entirely - thanks for your info

 

[Burnerman]

The B9 is a simple enough burner assembly, with the oil pump fixed to one end of the motor and the fan on the other. (BFP41 L3 pump I think?)
If you can separate this assembly from the burner frame, see if you can move the motor bearings up and down, and see that the fan is tight on the shaft. If the pump bearings are kaput, 9 times out of 10 there will be a kerosene leak visible. Go for a new pump in this case (but I would have thought there would be a kerosene pong really).
Just my opinion, but motor bearings tend to howl when worn - but the play in them can cause the fan to wander.
John

 

[Matt789]

Okay thanks i will either open it up later today or get someone over if there doesn't appear to be a way to get to it, can we safely rule out that there is air in the boiler given where I've bled?

Thanks all those who've helped so far