Alpha 240E - Noisey after Rad swap...

[Aragorn84]

Been doing some decorating/renovating in preperation for a new arrival, and as part of the job i replaced a radiator.

The system was drained down, the old rad removed, and the pipes capped off while plastering and other work was done. System was refilled and ran fine during this time, though i thaught it might have been a little noisier than before. A sort of watery rushing type sound. But there was a hole in the floor with the pipes exposed etc, so i figured it was just that.

Last week, i drained the system again, installed the new rad with new valves, and got it all refilled with a bottle of inhibitor. Rebled it again a few times to get all the air out and making sure it was filled up to the right pressure again.

The noise however has now got a lot worse. It seems to be worse after the burners been running for a while, it sort of builds up, starting as the same watery rushing noise, but getting louder and turning more into a drone at random times. At its worst you can literally hear the pipes vibrating/buzzing in the walls. It doesnt last long though, appears to fade away again if you ignore it. I will try to record the noise, but not sure if i can capture it.

At first i thought it was a balancing issue having disturbed things, but i tried turning the new rad on and off when the noise was at its worst, and it makes no difference.

I think the noise is actually coming from the boiler itself, when its running theres a distinctive vibration from the boiler and the pipework, and if you turn the boiler thermostat down such that the burner shuts off when its vibrating at its worst the noise immediately stops, despite the fact that the pump is still running etc.

Any ideas? I'm wondering if the draining down and refilling has dislodged some crap which has ended up partially blocking the heat exchanger :/

 

[Agile]

Every time you drain the system you lose inhibitor and introduce a new lot of oxygen.

Your problems are probably just caused by air in the system.

But draining it so often, and totally unnecessarily, just makes the problem worse!

Tony

 

[Aragorn84]

Thanks.

I've gone and re-bled it again tonight, two rads seemed to have a lot of air in them. Will see how it goes now.

Not sure why you deem it unneccesary to drain and refill? The old rad was smaller and pipes were in a slightly different place to the new one, and i wanted the pipes out the way while other work was going on. It made more sense to drain the system down and cap the pipes below floor level, than to leave two bits of microbore sticking out the floor with big heavy valves on the end of them waiting to get snapped by someone weilding a sheet of plasterboard or a length of skirting.

Wife would have been unhappy without heating for 4 weeks, and would have been equally unhappy if a leak ruined her new kitchen ceiling below...

Thus it needed drained to remove the old rad, refilled in between, and drained again after to fit the new rad. Not sure what else you could have done?

 

[Aragorn84]

I've given it another few days, bled the rads lots. No air to speak of present, but the noise remains.

I've noticed it reacts differently when on heating and hot water too.

On hot water the boiler fires up from cold, starts making the noise fairly quickly, perhaps within 10 or 15 seconds, sounds like kettling to begin with then it then changes in pitch, turns into a drone and sounds a bit like a aircraft flying overhead over a period of about 20seconds, before settling down to a constant and less broken sounding noise, albeit still a bit kettly sounding, but without rattling all the pipework.

On heating, the boiler fires up, and will burn for a while before making the noise, and the noise will last a LOT longer. With the boiler stat at maximum, it will sit vibrating all the pipework continuously for a good 5-10minutes. If you turn the stat down a bit to say half way, it'll tend to just start making the noise as the boiler clicks out, instead of building up to its crescendo. If at any point while its making the noise I turn the boiler stat down, which shuts off the burner but keeps the pump running, the noise instantly stops.

I tried to record the noise on DHW mode, but it didnt come out too well, will try again later putting the phone closer to the boiler. If I really crank up the speakers on the PC i can hear it, but i couldnt make it out on the phone speaker.

I really do get the feeling its something to do with the heat exchanger, given it seems to be related to temperature, and stops the instant the burner shuts off.

Thoughts?

 

[Aragorn84]

Tried to get another video but it still didnt come out that well :/

 

[Aragorn84]

No-one has any ideas?

Chemical Treatments? Power flush? New HX?

 

[Aragorn84]

This video sounds better

Most of the noise is just the fan/burner/water flowing etc, but you can at least make out the droning "light aircraft" sound on top in that video