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https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl DIY Forum >> Plumbing Questions >> Causes of boiler noises and pumping over? https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl?num=1105056479 Message started by oggy on Jan 7^th, 2005, 12:07am

Title: Causes of boiler noises and pumping over?
Post by oggy on Jan 7^th, 2005, 12:07am

I have problems with my vented c/h system making banging noises in the boiler and pumping over into the f/e tank.

The system is about 12 years old with TRVs on all but 2 rads. The Myson Orion Fanfare boiler was moved and extra rads added just over a year ago.

About 20 mins or so after it first comes on in the morning there is a rumbling/banging/rattling noise in the boiler for a few seconds and the system pumps over. Often it is then fine for the rest of the day, but sometimes it will repeat it later on. Occassionally it has done it repeatedly for 5-10 mins! At the point the rumbling/banging starts the sound of the water going round the rads dies down for a second and then surges (causing the pumping over) before going back to its normal speed.

I initially thought it was the pump as it was noisy and did jam once so I changed that, however it has not solved the problem. It's 3 speed and is currently set on 2. I tried turning it down to 1 (as is often suggested to stop pumping over) but this made it worse. Unfortunately, running it on speed 2 makes the water circulating round the rads quite noisy!

I also had problems the other day with the f/e tank overflowing and pulling in fresh water at the same time so I've temporarily got the cold feed to the tank turned off. What level of water should there be in the tank? Mine was about 2/3 full with the end of the overflow dipping down below the surface, although there was no leak from the cold feed. With the cold feed off and rads bled, the level is remaining at just below halfway but I obviously need to set a level and get the supply turned back on.
I realise the pumping over is not good for the system and needs fixing as it will be causing corrosion, so what are the likely causes? Searching various forums etc. suggestions seem to be:

faulty pump? - well it's been replaced and I've checked the electrics to make sure its not cutting out
pump too fast? - it's worse when turned down
bad design? - it used to be ok!
f/e tank level too high? - it's still happening with the level reduced and again it used to be ok!
a blockage? - possible, but all rads get hot (very hot!) so I think this is unlikely
faulty boiler thermostat? - I currently think this may be the most likely cause (especially with the very hot rads?) Is there a simple check/test I can do to confirm this before calling out a Corgi to fix it, bearing in mind the fault is intermittent?

Thanks in advance for any help/advice……..

Title: Re: Causes of boiler noises and pumping over?
Post by thescruff on Jan 7^th, 2005, 12:37am

Pump problem.

Boiler banging and not pumping over is lack of circulation.

However the force of the water being propelled up the pipe on its way to the header tank is freeing the impellor

scruff

Title: Re: Causes of boiler noises and pumping over?
Post by oggy on Jan 7^th, 2005, 1:00pm

Thanks for the reply but I recently changed the pump and this didn't fix the problem.

One suggestion has been to drain it all down and refill in case there is an air lock in there somewhere. Is that likely and would draining/refilling be worthwhile?

Thanks.....

Title: Re: Causes of boiler noises and pumping over?
Post by thescruff on Jan 7^th, 2005, 1:42pm

But have you checked the pump is working, prior to the banging.

Could be something else sticking that controls the pump like a microswitch in a motorised valve, or an over-run switch, if it has one, must check me little book if its in there.

scruff

Title: Re: Causes of boiler noises and pumping over?
Post by greg on Jan 7^th, 2005, 3:13pm

you say the boiler was moved, has the pump been moved too? did the problem begin straight after the boiler was moved?

Title: Re: Causes of boiler noises and pumping over?
Post by PEDANTICVINDICTIVEMAN on Jan 7^th, 2005, 8:25pm

When the boiler was moved, was it wired correctly, permanent live, switch live, pump live, plus what scruff said regarding sticking stats and microswitches

Title: Re: Causes of boiler noises and pumping over?
Post by oggy on Jan 8^th, 2005, 11:08pm

There are 2 motorised valves (HW & CH) which control the pump and I did manage to confirm that there was still a supply (simply with a voltage tester screwdriver) when the banging occurred and also it didn't sound like the pump was stopping! I'll try and check again, but with it being an intermittent problem it of course hasn't gone wrong today!!!

The boiler was moved over a year ago but the pump was not. There was the odd bang after the move but this was put down to air in the system and it seemed to settle down until recently. The move was done by pro's so I can only assume it was all done correctly!!

Today we turned the boiler thermostat right down to 1 and the rads are still too hot to touch so surely the boiler stat must be faulty. Do you agree? And would this cause the symptoms described?

Thanks again to you all for the help............

Title: Re: Causes of boiler noises and pumping over?
Post by JerryD on Jan 8^th, 2005, 11:48pm

wrote on Jan 8^th, 2005, 11:08pm:

The move was done by pro's so I can only assume it was all done correctly!!

lol ::) :o ::) :o ;D

Title: Re: Causes of boiler noises and pumping over?
Post by thescruff on Jan 8^th, 2005, 11:50pm

Turn the stat up, does the boiler come on ???, trn the stat down does it go off ???

Probably ok then.

You have two motorized valves how are they connected and where, also do you have an auto by-pass valve and where is it in relation to the pump.

scruff

Title: Re: Causes of boiler noises and pumping over?
Post by oggy on Jan 12^th, 2005, 12:21am

Well, the boiler stat has been on 1 for a few days and the system has been remarkably quiet - though the rads are still too hot to touch - much hotter than they used to be on 3 or 4!
I tried turning it up all the way to 7 - there was a click at about 2 but it did not fire up - not for at least a minute.
When it had been on 7 for a while the banging started again. I tried turning it back down but it did not go off until it was down below 2.

The pipe from the pump goes to a tee with a motorised valve on each branch - one to the rads, the other to the HW tank. There's no auto by-pass - at least not that I'm aware of!

Title: Re: Causes of boiler noises and pumping over?
Post by chtechie on Jan 12^th, 2005, 9:26pm

Not sure where Scruff is today - This bypass he mentioned is to allow the pump to circulate water when both valves are shut and the pump over run is operating. So you would normally find a 15mm pipe connected to the flow pipe leaving the pump (before it gets to the valves) and connecting to the boiler return pipe it will also have a valve of some sort either auto or manual to regulate the amount of water that can pass along the bypass.

David.
______

Title: Re: Causes of boiler noises and pumping over?
Post by thescruff on Jan 12^th, 2005, 9:41pm

wrote on Jan 12^th, 2005, 9:26pm:

Title: Re: Causes of boiler noises and pumping over?
Post by chtechie on Jan 12^th, 2005, 9:52pm

Ah - Alive & well in the smoke I see

Title: Re: Causes of boiler noises and pumping over?
Post by thescruff on Jan 14^th, 2005, 9:39pm

wrote on Jan 12^th, 2005, 9:26pm:

The auto by-pass is also to control the system head as and when the thermostatic radiator valves close, which in turn stops the system becoming noisy.

scruff

Title: Re: Causes of boiler noises and pumping over?
Post by oggy on Jan 16^th, 2005, 12:59am

There is no by-pass as there were no TRVs originally. There are however still a couple of rads without TRVs.

So anyway, surely red hot rads with the boiler stat on 1 suggests the stat is faulty doesn't it? If so, how much roughly?

Incidentally what would you suggest is the lifespan for a Myson Orion Fanfare boiler?

Thanks....

Title: Re: Causes of boiler noises and pumping over?
Post by thescruff on Jan 16^th, 2005, 1:33am

Obviously its possible, and although I dont know your boiler, I would look elsewhere, for circulation problems, check any motorised valves by removing them, check for scale and sludge in the boiler heat exchanger.

check the gas valve is not sticking.

Is the problem more prominant when the boiler has been off for a few hours.

Title: Re: Causes of boiler noises and pumping over?
Post by thescruff on Jan 16^th, 2005, 2:29am

What model number orion fanfare is it ???

Title: Re: Causes of boiler noises and pumping over?
Post by oggy on Jan 17^th, 2005, 12:39am

It's an Orion Fanfare 60Si, if that helps!

The problem was happening regularly 20 mins or so after it first came on, but would also do it later on in the evening too.

However it's been quiet for a good few days now since the boiler was reduced to 1. Also the f/e tank level is currently lower than it had been as the supply to this is still turned off!

Wouldn't circulation problems lead to cold spots in the system? Everything is lovely and hot at the moment! And the motorised valves seem to be working ok.

So it sounds like I need to get a Corgi in to check out the gas valves....

Title: Re: Causes of boiler noises and pumping over?
Post by woodsmith on Jan 17^th, 2005, 8:18am

Oggy wrote;

"What level of water should there be in the tank? Mine was about 2/3 full with the end of the overflow dipping down below the surface"

Do you think that having the overflow pipe dipping into the water in the tank may cause a problem? As the heating cools water will be drawn up the overflow pipe and may be causing some sort of air lock which clears when the heating gets up to a certain temperature?

Just a thought ???

Keith

Title: Re: Causes of boiler noises and pumping over?
Post by billythekid on Jan 17^th, 2005, 12:11pm

wrote on Jan 17^th, 2005, 8:18am:

no keith, he meant the actual tank overflow, not the expansion pipe from a cylinder. It fine to have the overflow in this way, in fact thats how a by-law 30 kit comes. as the tank level drops all that will be drawn from the overflow is air, to the tank space. Still could be airlock, although not for this reason.

Title: Re: Causes of boiler noises and pumping over?
Post by woodsmith on Jan 17^th, 2005, 6:40pm

Thanks BTK,

Ah well, would have been a good idea if I hadn't got my overflow mixed up with the expansion pipe :-[ ::)

Title: Re: Causes of boiler noises and pumping over?
Post by thescruff on Jan 17^th, 2005, 7:27pm

http://www.partsarena.com/baxi/

Fault chart can be found abovelink.

Does the main burner turn off before a flow temperature of 60c when on 1 ?

No; Disconnect main solinoid lead, does the main burner shut down ?

Yes change boiler thermostat,
No change gas valve.

scruff

Title: Re: Causes of boiler noises and pumping over?
Post by oggy on Jan 18^th, 2005, 11:51pm

Thanks for the help guys, I'll investigate further soon.....