Boiler banging when it fires

[doobmiester]

Hello there everyone, decided it's about time i got help with my boiler, i'm an idiot when it comes to these things & i'm too mean for a plumber, so i hope there's some fabulous people out there can come to my assitance.

I've got a gas boiler, a "Maxol homewarm 600, Wall mounted Balanced Flue Heat Generator" apparantley. For probably about 20 months or so, it been banging when it ignites. I've just ignored it, but the wife has finally had enough. It used to just bang once or twice but now it bangs 5 or 6 times, REALLY LOUDLY & in batches of 3 or 4, IE; 3 or 4 rounds of 5's or 6's. Then it makes a whoosy sort of noise & then a watery sort of noise before being as quiet as a mouse until next fire up. It does sound like it's going to explode every time. It makes me so proud!

Anyway, what does a complete amatuer like myself do to rectify said matter?

Thanks in advance.

 

[pannierstan]

Check the pump. Usually thats the cause of boilers banging when they first light.
The vibration then kick starts the pump.

Stan

 

[kevplumb]

 

[namsag]

Pretty sure these have a pump over run stat on them possibly built into main boiler stat which if sticking would give you the symptons you have.

 

[lor]

never herd such nonsese except form my boss .

 

[doobmiester]

Pretty sure these have a pump over run stat on them possibly built into main boiler stat which if sticking would give you the symptons you have.

You sound like a knowledgable fellow, unfortuately however, i'm not. Could you translate into really stupidly simple laymans terms for me, pretend i'm a child confronted with my first attempt at writing. Keep it easy, i did say i was an idiot. What do i do then?

 

[Fluffster]

If it is what Lor says then your only option is a Corgi registered engineer.
Other wise if you have ago messing with the gas valve it really will explode and your missus will really have something to be peeved about.
Pete

 

[namsag]

By the description of your fault as in you hear banging and then a woosh of water this sounds like a pump fault as your boiler is a low water content type which quickly boils up and gets very noisy.

Lets clear up what the noise sounds like is it

A.... Like an explosion within the boiler the instant it lights

B... Like some some one hitting boiler and pipes with a hammer loud clanging and clanking about ten seconds after boiler initially fires up.

Also if boiler is on for several hours the boiler will cut off and on with the boiler thermostat does burner relight perfectly each time..

Is it only after the timer has gone off or room and cylinder stats satisfied and at the start of next on period you get the noise.


Most low water content boilers have a pump over run on them to dissipate heat after the demand for burner to be on has stopped . This senses heat within the boiler and keeps the pump on for about ten minutes afterwards.

The pump gets it power from the actual boiler so what happens is when a pump over run stat is faulty instead of the pump coming on at the exact same time as the boiler it does not come on till heat is sensed in the boiler by which time the water in the heat exchanger is starting to boil and starts banging and clanking through pipes.

Even if it doesn`t have a pump stat it is not uncommon what pannerstan suggests

If it is this best get someone in as its into appliance control box

If it is explosive ignition it needs a service urgently

 

[pannierstan]

never herd such nonsese except form my boss . I would guess its to do with explosive ignition,had similr probs in past due to gas valve being set up incorrectley.u measure burner pressure in an unusual place ,ie not on the valve. Of course it could be a nmber of other things to do with ignition eg electrodes, flue recirculating

O.K wise guy then why is there sounds of water if its to do with ignition.
And thinking on why doesnt it do it everytime the boiler lights for the rest of the demand period.
You will learn one day boyo

 

[lor]

sorry I didnt read it carefully. question is boiler bangs when it fires. I assumed he meant on ignition. pannierstans ,your first reply is badly written .
pumps do not kick start themselvesinto life from vibrations.pure bull

 

[HarrogateGas]

sorry I didnt read it carefully. question is boiler bangs when it fires. I assumed he meant on ignition. pannierstans ,your first reply is badly written .
pumps do not kick start themselvesinto life from vibrations.pure bull

so when you tap a pump to kick start it when its stuck that isnt a vibration??

Im with pannierstan on this ive known stuck pumps go from just shutting the cupboard door they are housed in. and ive known the very scenario which Pannierstan describes.

Its you speaking nonsense and poorly writing your posts without even thinking what you are saying.

 

[pannierstan]

pumps do not kick start themselvesinto life from vibrations.pure bull

I think you find they do.
If you dont agree then explain why the pump starts after the banging!
Is it bloody magic! or the pump fairy with her screw driver.
Get some experience Lor then come back in ten years

 

[lor]

well kevplumb agrees with me

 

[pannierstan]

well kevplumb agrees with me

That dont mean you are right boyo

 

[doobmiester]

By the description of your fault as in you hear banging and then a woosh of water this sounds like a pump fault as your boiler is a low water content type which quickly boils up and gets very noisy.

Lets clear up what the noise sounds like is it

A.... Like an explosion within the boiler the instant it lights

B... Like some some one hitting boiler and pipes with a hammer loud clanging and clanking about ten seconds after boiler initially fires up.

Also if boiler is on for several hours the boiler will cut off and on with the boiler thermostat does burner relight perfectly each time..

Is it only after the timer has gone off or room and cylinder stats satisfied and at the start of next on period you get the noise.


Most low water content boilers have a pump over run on them to dissipate heat after the demand for burner to be on has stopped . This senses heat within the boiler and keeps the pump on for about ten minutes afterwards.

The pump gets it power from the actual boiler so what happens is when a pump over run stat is faulty instead of the pump coming on at the exact same time as the boiler it does not come on till heat is sensed in the boiler by which time the water in the heat exchanger is starting to boil and starts banging and clanking through pipes.

Even if it doesn`t have a pump stat it is not uncommon what pannerstan suggests

If it is this best get someone in as its into appliance control box

If it is explosive ignition it needs a service urgently

Hi there Namsag, it's option B, about ten seconds to the banging, it ignites no problem after cutting out with the thermostat, but still bangs again on re-ignition. It's not as loud if the boiler has only been off for less than hour, after an hour or so it bangs at full decibels!

So it's the pump over run stat? Do i need a proper plumber or can an enthusiastic & moderately intelligent fellow like myself accomplish repair, with all you good chaps help obviously!?

Thanks for any advice.