C & M Brittony 80 making a whining noise.

[grill]

Evening All,

Was called out to a C & M brittony 80 Combi tonight that was making a noise like it was going to take off.

Basically when i ran the HW the boiler started to scream just before it modulated down. When modulated down the noise stopped. I played about with teh water flow to get it to modulate down and this was the only time it seemed to whine. Sounds like a jet engine about to take off.

Tried to identify the sound and i think it is the fan. It was hard to heard though as it is housed behind the combustion cover and i don't like running them with this off??

Am i right in thinking it is the fan??

As an aside the bath tap will not turn on now due to all the turning off and on. It was stiff to start off with. I told the householder she would need to get someone in to fix it and she informed me that she wasn't convinced i hadn't broke it!!!! How do you deal with that??

G

 

[bones001]

in the right hand hydraulic block take the c.h pipe out and there is a filter in there which becomes blocked causing this noise

 

[grill]

Hi Bones,

Now how the hell was i suppoused to work that one out!!!!!! Why though does the noise only happen when the boiler modulates down??

Grill

 

[bones001]

I'm not sure but I think its to do with the c.h water in the boiler getting too hot when the hot water is ran. I went to one that was sounding like a whale singing when the hot water was ran and I phoned the tech line and they told me it was a partial blockage in the primary heat exchanger and he recommended replacing it. I took it off and flushed it out (it seemed fine) put it back together and the noise was still there. thats when i took that pipe off and found the filter full of black ****. cleaned it out and it was fine.

 

[grill]

Where exactly is it mate?? You got a diagram by any chance. I have no manual for this one.

G

 

[bones001]

looking at the boiler you have 4 90 degree angled pipes which have a nut on one side and a clipped o-ring connection on the other. the central heating one on the right hand side. take this off and in the plastic hydraulic block where the o-ring side of the pipe comes out of, it is in there.

 

[grill]

No problem sir,

I know exactly where you mean now. That truly is a stange one. Knowledge is power and you have the power. Ill try this first before i bung in a new fan!!!

Boilers never cease to amaze me!!!!

G

 

[bones001]

yeah try that first and i apologise in advance if i have wasted your time and it turns out to be the fan after all!

 

[chrishutt]

It's nothing to do with the fan. The main heat exchanger makes this noise if flow is restricted by corrosion debris, e.g. in the return filter as described. The noise occurs on high flame usually just as the max temp is approached, followed by low flame.

 

[grill]

Hi Chris,

Yeah that is exactly when it happens.

Another school day for me!!!

G

 

[chrishutt]

If you want a manual check out the Genesis MI from the Baxi Parts Arena site. It's virtually the same boiler but the Baxi MI are much better than the Chaffoteaux ones. Includes nice diagram of the filter location.