Baxi Solo boiler problems

[martin4533]

Have got a Baxi Solo heat only boiler installed approx 2.5 years ago. Had to have a new heat exchanger after a few months and a new Pcb just before end of second year. I am hearing a strange noise in the last couple of weeks which sounds very similar to first problem with heat exchanger so very probable that it's fryed again ( which is how the engineer described what happened the first time). Am I unlucky or is this a common problem with these boilers ?? I am out of Warranty so sounds like could be facing a big bill unless anyone has any ideas / suggestions ??

 

[rojaca]

If heat exchanger is making noise as its getting warm/hot it's most likely sludge/debris.

 

[martin4533]

Thanks Rojoca but i don't think that is the problem here. Had power flush when boiler fitted +last time, the engineer said it was heat buckled the exchanger and fitted a pump overrun timer to help disperse heat. Been alright since until couple of weeks ago, which is why I wondered if this model has a particulary fragile heat exchanger .

 

[gas4you]

Is this the Baxi Solo HE?

They had problems originally with the HE plugs going at the back of the HE.

 

[rojaca]

By pump overun timer, do you mean your installer has wired the pump back to the pcb. I've found that this actually has the opposite effect of helping the blr loose residual heat.
If system was powerflushed when fitted, then powerflushed again si there a possibilty that your system may be sludged again- perhaps through pumping over, drawing air in etc. Would check the water quality in the header tank and draw some off at the bottom of your system.
Baxi do a fixed price repair , but to be honest if you've got a system fault that needs correcting, which may be causing corrosion/sludge, then you may be throwing good money after bad without ever curing the problem.

 

[martin4533]

Thanks Dave
Yes it is a Baxi Solo 24 HE but doesn't appear to be any sign of leak just starting to make a howling noise after been running for a while ( 20 min) , usually just before switching off. Noise is the same as before and can be almost eliminated by turning the water temperature down on boiler.

 

[martin4533]

Baxi heat team installed the overrun timer .Don't think it's wired back into Pcb but linked into power supply to pump, controlled by stat. No overpumping or problems with air in system and I don't think it's a sludge. Boilers in loft so guy said residual heat was the cause cos nowhere to go hence overrun timer ?? Has been fine for couple of years but your right , don't want to keep replacing if fragile boiler or system fault. Can't quite get my head round how the water can get hotter when boiler switched off, enough to bugger up heat exchanger ?

 

[Netdragon]

Sounds to me like you are getting a blocked/sludged heat exchanger again.

If not done so get a magno clean fitted on the system to protect your boiler this has a nice magnet that collects all the debris in a sealed pot that you can isolate and clean regular.

The fan could also be the source of the problem unlike old boilers the speed of the fan adjusts this lowers or raises the pull on the gas valve and adjusts the pressure as required it could be reducing the fan speed and making the noise alter.
Simple way is to let the boiler start going and switch off the boiler at the boiler controls if it still goes on then its the heat exchanger. if it stops look at boiler/fan.