Powermax 185 - Whistle

[thebakery]

We have a powermax (185) that has just started whistling and is approx 5 years old. A good number of houses in our close proximity also have the same annoying problem. British Gas don't seem to know what to do - any advice would be greatly appreciated before we are all slapped with a fine from the council for noise pollution
The boiler whistles when heating the HW only (does not appear to happen when the CH is on) and although noisy in front of the boiler it is nothing compared with the sound outside the house. The noise appears to become amplified through the flue which protrudes through the roof ridge tiles.
We haven't descaled the boiler since we've owned the property (4 years) - (should we )and have a water conditioner "Limefighter" fitted to the cold water mains (does this need to be replaced regularly )

Having read a few similar articles a number of solutions have been suggested:
Gas mixture, heat exchanger, system flush through / descale, fan

If anyone has managed to fix this problem I and many of my neighbours would be very very grateful for some advice.

 

[Agile]

The noise is associated with the fan or gas combustion.

Has it been properly checked with a flue gas analyser?

Tell BG that you are not inpressed with the competence of whosoever came and they will send a Lead Technician who knows a little bit more.

They advertise that they know what they are doing so get them to prove it by sorting out this problem.

Tony

 

[Vic Spanner]

The noise is associated with the fan or gas combustion.

Has it been properly checked with a flue gas analyser?

Tell BG that you are not inpressed with the competence of whosoever came and they will send a Lead Technician who knows a little bit more.

They advertise that they know what they are doing so get them to prove it by sorting out this problem.

Tony

Spot on advice.
Im pretty sure BG are not allowed to touch the gas valves on them so they call us in.
Also had a couple where the burner head has been the problem (Damaged gauze)

 

[thebakery]

Thanks guys - had BG out today in fact. He poked a suction tube down inside and nodded - was this a flue analyser?

Does the fan only come on when HW is being heated? (thought this would come on regardless of CH or HW) The problem only happens after running HW.

On a seperate note should I descale the boiler or replace the water conditioner on a regular basis? If so how often (does this depend on area water conditions?)

Thanks in advance

 

[thebakery]

also whatever the problem it is pretty common as just about everyone on our estate with this boiler has recently started to experience the same problem (all the houses were built approx 5 years ago) This made me wonder about it being a scale related problem

 

[ollski]

Probably if you have an increasing resonance then there is a good chance the baffles are beginning to corrode. Depends on the exact noise.

 

[thebakery]

It's a high pitched whine that starts to come on about 2 mins after the boiler has fired up to reheat the core.
Where are the baffles located? - the noise gets louder in the loft but it's really difficult to isolate.

 

[Baxi-Remeha]

could try getting it serviced, this will tell you if the baffles are corroded, and they can also tell you weather the air/gas ratio is correct....

 

[thebakery]

Just been serviced by BG yesterday. All i saw him do was poke a tube down through a hole in the top of the unit (I assume that the other end was connected to the flue analyser). He didn't do anything else - should he have done?
Where are the baffles - in the flue?

 

[ollski]

The baffles are long twisted metal rods in the heat exchanger but definitely not a diy job even for a look, if you remove the burner to get at the baffles you will require a new gasket.

 

[Agile]

I am sorry to tell you that BG have NOT serviced your boiler!

All they have done is to use an analyser to confirm that the flue gases are not containing too much carbon monoxide.

A proper service will involve opening up the boiler and inspecting and cleaning the inside of the boiler. It will also involve resetting the fuel/air mixture if necessary but its suggested above that BG are not allowed to do that.

The baffles create turbulance in the flow of combustion gases within the boiler and improve heat transfer.

You have not told us what is the situation with the noise. Has that been cured? If not whats the next stage?

Tony Glazier

 

[thebakery]

the noise is still evident the engineer is apparently leaving the call open and consulting with a colleague - I don't hold out a great deal of hope as my neighbours have had the same problem for some time and BG have yet to resolve it!
What would actually cause the noise - is it the exhaust gasses flowing over the baffles? Why would it only occur when HW is on?

 

[simond]

We have replaced a few premix fans on the Powermax 135.

Cant recall working on the 185 and don't know whether it modulates. But it is likely that being a hybrid combi, the unit will be on full modulation on hot water mode, thus if it's a modulating unit the fan will be giving it everything at that time.

if the bearings are on the way out, this would exacerbate the noise.

Simon

www.hwch.co.uk

 

[Vic Spanner]

Just been serviced by BG yesterday. All i saw him do was poke a tube down through a hole in the top of the unit (I assume that the other end was connected to the flue analyser.

Will if he was using a flue analyser he would have been sticking his probe in the wrong place..The sample point is at the bottom of the unit just above the sump joint

 

[Eyesee]

Get BG back to check working pressure at the meter and appliance, gas supply should be 22mm to within 300mm of gas valve, strip down and inspect the condition of the baffles, burner and injector. While the appliance is running turn off the gas supply(which he should have done on the service to check the FSD) if the noise disappers I would change the gas valve. Had the same problem with a powermax 155