Boiler Experts, loud random buzz on fire up

[fossyant]

We have a trusty old Baxi Solo2 PF40 thats 27 years old. Its working fine, and after a drain down and loads of inhibitor its running very vell.

We've had, very occasionally a very loud buzz vibration when the boiler starts. It's random ond maybe occurs once a day, twice if heating on all the time.

It appears to be coming from the gas valve, but, of course, being so random and only once a day you don't have any time to rush into the kitchen, remove the cover etc.

It's totally fine 99.9% of the fire ups.

I've just cleaned up the electrical contacts and popped off the solenoid in case anything looks amis, but its fine. Contact cleaned the connections and a bit of lube, and reassembled.

Any ideas what could cause it. Faulty solenoid ? Thats an easy part to replace, but would get a gas engineer in for the gas valve. Fortunately parts are still available.

 

[classic33]

Is the fan causing the noise?

 

[newts]

When was the last time it was serviced/cleaned?

 

[the_mikey]

Complete stab in the dark but air intake fan bearings could be worn, typically you'll know this by intermittent fan vibration noise that is likely to worsen as the wear increases, sometimes this is triggered by the fan changing speed, especially when first switched on and can sometimes settle down quickly and remain silent until the next time the fan is re-activated.

 

[wafter]

I have what appears to be a similar problem; sounds to me like a solenoid with dicky contacts oscillating open/closed until it finally manages contact and engages.. that said I know naff all about central heating so could be well wide of the mark.

 

[presta]

Mine's made a noise ever since it was new. It sounds like the vibration from the pump travelling along one of the pipes so that it buzzes against something it's touching. The sound travels all round the house, but I only notice it in the middle of the night when it's quiet.

 

[fossyant]

Long time since it was serviced, the sound lasts couple of seconds, sounds like a loud buzzer then goes off. No grumbling etc, so not a bearing issue, just an occasional loud buzz (bit like a quiz show buzzer).

It's not stopping the boiler fire up, as the gas comes on and it ignights, even if it buzzes, but could well be a sticky solenoid.

 

[TissoT]

When the boiler was drained down and refilled did you get the air out of the system.

Also It could be a fault on the pump.

Is the Flue Clean

 

[fossyant]

When the boiler was drained down and refilled did you get the air out of the system.

Also It could be a fault on the pump.

Is the Flue Clean

Yes, all done. The buzz has been a random issue for a couple of years, so it's nothing new. Just 'the boss' want's it fixed.

 

[cyberknight]

the bees inside need feeding

 

[the_mikey]

Yes, all done. The buzz has been a random issue for a couple of years, so it's nothing new. Just 'the boss' want's it fixed.

Pumps can also create noise, especially if there is some air in the system somewhere as this makes it easier for the water in the pipes to become media for transmitting pump noise, it can also lead to pipes physically oscillating somewhere.

I have what appears to be a similar problem; sounds to me like a solenoid with dicky contacts oscillating open/closed until it finally manages contact and engages.. that said I know naff all about central heating so could be well wide of the mark.

Use an old AM radio, select MW and tune to an empty frequency, and when the noise occurs, do you get lots of interference on your radio? That might confirm problems with your solenoid.

 

[wafter]

Use an old AM radio, select MW and tune to an empty frequency, and when the noise occurs, do you get lots of interference on your radio? That might confirm problems with your solenoid.

Thanks - that's an inspired idea I'd never have thought of! Not sure as I have access to such a thing as an AM radio however but will certainly give it a try if I have

As it happens it seems to have been behaving itself recently..

 

[dan_bo]

When was the last time it was serviced/cleaned?

It's Fossy's it'll be cleaner than his bike.

 

[newts]

It's Fossy's it'll be cleaner than his bike.

Unless you're 'gas safe' registered you shouldn't be dismantling/cleaning/repairing a gas boiler. The minimum requirement would be a gas soundness test before & after any work is undertaken. Does the op have such test equipment?

 

[dan_bo]

Unless you're 'gas safe' registered you shouldn't be dismantling/cleaning/repairing a gas boiler. The minimum requirement would be a gas soundness test before & after any work is undertaken. Does the op have such test equipment?

Calm down Llynn Foulds Wood