I guess the froth inhibits contact between heat exchanger and water passing through, so HE overheats and sounds like a piston engined plane passing overhead. There may be a chemical that will suppress frothing (as added to decent inhibitors) - if someone clever could identify it, it would save you draining the whole system.
split post: biasi boiler
- Thread starter dsinclair999
- Start date
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I cunningly fitted the world's most comprehensive draining points in the system, so draining is a piece of the proverbial. And with auto vents all over the shop, bleeding is bleeding easy.
I'll drain and run it for a week or so on l'eau frais, redrain and add F1. That did not make noise.
Still need to check the CO2 - sanity check and all that.
I'll drain and run it for a week or so on l'eau frais, redrain and add F1. That did not make noise.
Still need to check the CO2 - sanity check and all that.
I drained the majority of the water with Protex. I have some F1 to add, after I have run the CH a couple of times over the next couple of days.
It seems to be quieter, but not silent. Still some bellowing at high power settings once the H/E is hot, though not as audible through the rad pipework.
I suspect that either the remaining Protex is still causing some frothing, or the H/E coil still has some Protex "lining" on it/in it.
I'll post the results once concluded, one way or another.
It seems to be quieter, but not silent. Still some bellowing at high power settings once the H/E is hot, though not as audible through the rad pipework.
I suspect that either the remaining Protex is still causing some frothing, or the H/E coil still has some Protex "lining" on it/in it.
I'll post the results once concluded, one way or another.
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I have no idea what F1 is?
However with Protex at £3 and the "proper inhibitors like Fernox and Sentinel X100 at about £15 I would guess that they might be a little better?
I dont think that British Gas use Protex!!! ( Their moonlighting engineers perhaps! )
I take the view that the best quality products are probably the best and would never advise using cheap makes. Did Screwfix say why they were discontinuing protex?
I am more interested in the foghorn noise at full power!
I also wonder which knob you mean when saying the "B knob" ???
Tony
However with Protex at £3 and the "proper inhibitors like Fernox and Sentinel X100 at about £15 I would guess that they might be a little better?
I dont think that British Gas use Protex!!! ( Their moonlighting engineers perhaps! )
I take the view that the best quality products are probably the best and would never advise using cheap makes. Did Screwfix say why they were discontinuing protex?
I am more interested in the foghorn noise at full power!
I also wonder which knob you mean when saying the "B knob" ???
Tony
The B knob or control is the left hand one on the Biasi - slightly comical that the RH one is the A control.
The Protex wasn't £3 - it was sold as a bonafide inhibitor. The same stuff is sold by Screwfix now called "No Nonsense" or something similar. I used bucket loads of Protex in France with no problems. They tend to use car antifreeze - dual purpose!
Anyhow, a day on and the foghorn is back. Just got in and ran the shower and the noise is back with a vengeance. Bolleau. Looks like Protex is not the cause.
Back to the drawing board.
F1 is Fernox F1 - very good, not cheap.
The Protex wasn't £3 - it was sold as a bonafide inhibitor. The same stuff is sold by Screwfix now called "No Nonsense" or something similar. I used bucket loads of Protex in France with no problems. They tend to use car antifreeze - dual purpose!
Anyhow, a day on and the foghorn is back. Just got in and ran the shower and the noise is back with a vengeance. Bolleau. Looks like Protex is not the cause.
Back to the drawing board.
F1 is Fernox F1 - very good, not cheap.
Opel Fruit said:
Now lets consider for a moment that its NOT a foghorn sound !
Perhaps its a water flow linked problem?
If you get a large spanner, remove the front cover of the boiler when its cold and locate the big nut holding the return pipe connection to the top of the plastic rear part of the pump.
Very carefully loosen that nut! Less carefully if you depressurise the boiler first. Only loosen it until you can just twist the bent 22 mm pipe it connects.
Select a mid position for the pipe and HOLD it exactly there as you retighten the nut.
Refill if needed and see if it has made any difference!
Tony Glazier
I'll give that a try - I used to have resonance problems with Vaillant 28kW combis (14 years ago - back in the days when Vaillant electroplated the internal Cu pipework) and this was always the diverter valve casting. Some were noisy, some weren't. Many were changed. All to Vaillant's cost...
I think I'll wait until I drain and add the Fernox F1 - not sure I want torrents of water on the control board - there's careful and there's Sod's law!
I think I'll wait until I drain and add the Fernox F1 - not sure I want torrents of water on the control board - there's careful and there's Sod's law!
Drained, moved return pipe as suggested, refilled using Fernox F1.
May be better - need to keep an ear open!
May be better - need to keep an ear open!
No - it's the same....
Answers on a postcard
Answers on a postcard
Are you able to tell if its a pipe resonance or an inlet pipe foghorn noise ( which only normally happens on minimum power ).
Has the boiler been checked on min AND max with an FGA ? If so what were the results?
Tony
Has the boiler been checked on min AND max with an FGA ? If so what were the results?
Tony
The CO2 was checked at both top and bottom power settings - they were 8.8% at the bottom end and 9% at the top end. The guy reckoned these were a bit lean, but as they were in spec, left them alone.
As for the noise - it is a little hard to describe. It isn't related to the inlet air - this boiler has the revised inlet hose with additional holes in it. The noise ONLY happens above about 25kW AND when the flow temp has reached more than about 58C. So we notice it ONLY when running a tap at full chat, so the boiler is working hard OR when the ch is running and the flow temp has reached 58C AND the burner is firing at >25kW still. Once the ch flow temp rises more, the burner modulates down and the noise goes completely. Unless the burner modulates up considerably, the noise never returns during the heat call. The burner will obviously modulate up if a tap is opened fully during heat call, and the noise returns for the duration of the tap being open wide.
The noise itself is a low frequency drone - very much like resonance. Sometimes this has a "hammerdrill" quality to it. The boiler vibrates (hums) whilst this is happening. This noise travels through the rads too, to some degree. Interestingly, the sound appears to be carried by the water - some of the pipe is Speedfit, which would tend to decouple any purely mechanical vibration/noise.
As for the noise - it is a little hard to describe. It isn't related to the inlet air - this boiler has the revised inlet hose with additional holes in it. The noise ONLY happens above about 25kW AND when the flow temp has reached more than about 58C. So we notice it ONLY when running a tap at full chat, so the boiler is working hard OR when the ch is running and the flow temp has reached 58C AND the burner is firing at >25kW still. Once the ch flow temp rises more, the burner modulates down and the noise goes completely. Unless the burner modulates up considerably, the noise never returns during the heat call. The burner will obviously modulate up if a tap is opened fully during heat call, and the noise returns for the duration of the tap being open wide.
The noise itself is a low frequency drone - very much like resonance. Sometimes this has a "hammerdrill" quality to it. The boiler vibrates (hums) whilst this is happening. This noise travels through the rads too, to some degree. Interestingly, the sound appears to be carried by the water - some of the pipe is Speedfit, which would tend to decouple any purely mechanical vibration/noise.
My suspicion would be some blockage or debris in the main heat exchanger. Was the system thoroughly flushed prior to boiler installation? Was a chemical cleaner used? You could try flushing though the heat exchanger using mains pressure water to try to clear any debris out.
By the way sorry that the Protex thing turned out to be a red herring.
By the way sorry that the Protex thing turned out to be a red herring.
Could you repeat the loosening the nut on the flow connection on the left as well just to eliminate that.
Has the manufacturer's service agent investigated as its presumably under warrantee.
I doubt its debris in the heat exchanger. This is difficult to flush mechanically because there are four loops in parallel inside.
Has anyone used a mechanical stethoscope to try to determine the source of the noise?
For that matter has the pump impeller been visually inspected for any debris blocking it?
Tony
Has the manufacturer's service agent investigated as its presumably under warrantee.
I doubt its debris in the heat exchanger. This is difficult to flush mechanically because there are four loops in parallel inside.
Has anyone used a mechanical stethoscope to try to determine the source of the noise?
For that matter has the pump impeller been visually inspected for any debris blocking it?
Tony
I bow to Tony's superior knowledge on these boilers. However in general where a heat exchanger has parallel channels, it's relatively easy for one to get blocked since the flow will divert to the other channels rather than try to force through the blockage. As Tony says, very difficult to flush through for same reason.Agile said:
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