Anyone know oil boilers?

[Furbo]

We’ve got an elderly Trianco Eurostar which was working fine until we had it serviced. Now, it pops and thuds when it is running.

We’ve had the engineer back twice and he has been unable to resolve it. Today he has said we need to get a second opinion, because he cannot fix it.

Any ideas chaps?

[Voguely]

Where are you based? Not much idea about boilers myself, but I've been very impressed with the company we use to service ours (central Beds area, think they are based in north Herts) - pretty much took ours apart and put it back together last year and seemed very knowledgeable.

[Furbo]

Voguely said:

Where are you based? Not much idea about boilers myself, but I've been very impressed with the company we use to service ours (central Beds area, think they are based in north Herts) - pretty much took ours apart and put it back together last year and seemed very knowledgeable.

Nottingham

[boyse7en]

Have you run low on oil recently? Could be the oil line needs bleeding.

[Richard-D]

If it started directly after a service I'd be wondering if he's put the wrong nozzle in.

[Furbo]

Richard-D said:

If it started directly after a service I'd be wondering if he's put the wrong nozzle in.

He has reduced it one size an it's still doing it. But I suspect it is something like that.

[GasEngineer]

Can you tell whether the pops and thuds are coming from the burner or the pipework/heat exchanger jacket?

Could be "kettling" when the boiler heats up indicating air in the system or a circulation issue eg faulty heating pump.

[Furbo]

GasEngineer said:

Can you tell whether the pops and thuds are coming from the burner or the pipework/heat exchanger jacket?

Could be "kettling" when the boiler heats up indicating air in the system or a circulation issue eg faulty heating pump.

I can't.

The engineer said he thought pump. But it started the moment after he'd finished servicing it and I am not big on coincidences.

[Richard-D]

Furbo said:

GasEngineer said:

Can you tell whether the pops and thuds are coming from the burner or the pipework/heat exchanger jacket?

Could be "kettling" when the boiler heats up indicating air in the system or a circulation issue eg faulty heating pump.

I can't.

The engineer said he thought pump. But it started the moment after he'd finished servicing it and I am not big on coincidences.

You could be able to determine from the flue (If you watch the water vapour/mist at the outlet). If there's a pulse when it thumps it would confirm it's in the burner.

[JoshSm]

Depends what's been fiddled with.

First thing is to work out if it's the water boiling or something else.

Can you increase the pump speed and see if that changes anything? Setting the pump to a slow speed can trigger kettling and someone might have messed with it.

[Furbo]

He was at the pump yesterday so I imagine he will have tried speeding it up.

As for watching the flue, there are no visible emissions.