Baxi Duo-Tec 24HE Squealing When Running Hot Water

[SamiH]

Had a Baxi Duo-Tec 24HE installed just over two years ago. Typically, about a week ago, around a week after the warranty expired(!!!!) it started making a loud and high pitched squealing noise when hot taps are turned on. It got progressively worse over a few days and has now 'plateaued' at an almost unbearable volume. It happens at no other time, only when hot water is demanded at almost full flow. It does stop when the flow is reduced, but obviously I don't want to wait half an hour for a bath to run. I have tried reducing pressure in the system by partly draining and also a complete drain and refill of the system when I had to sort out a leaking rad valve today. After the full drain and refill the noise was dramatically reduced to a whisper, and at times none existent, but this lasted about 30 minutes (could this have something to do with the central heating taking roughly the same amount of time to heat right up?). Had the cover off and there's no obvious place the sound is emitting from. Please help.

 

[kdoheating2011]

you'll find that the right hand brass block behind the pump is causing your fault.

 

[SamiH]

Thanks for the reply. Can you elaborate at all, such as the name of the part if possible? Is it fairly easy to sort out?

 

[liquidfreeze]

I'd be checking the inlet cold water filter first. It's a cartridge directly below the hall effect sensor. Housed inside the hydraulic inlet assembly. That's the brass part behind the pump. It also has a flow restrictor inside. I'd guess that's where the squeal is coming from. The next place may be the plate heat exchanger. However if your not gas safe the next piece of advice would be to not fiddle with it. Hope that helps you.

 

[kdoheating2011]

not really a diy job as gas valve needs removing to access the brass so u can remove the guts of the valve ,if u carnt put up with the noise get a gas safe engineeer to sort for u.

 

[SamiH]

Thanks again for information, was considering doing it myself as it seems pretty straight forward to me. However, going on your advice I will get the guy who fitted the boiler to come sort it. Just one more question though- is it a case of a filter cartridge being cleaned or do they generally need replacing? Just wondering for expense purposes really. Think I will have to look at some kind of water softener/ inline magnetic treatment too, our water here in Kent is heavier than lead.

 

[liquidfreeze]

The cartridge probably will only require cleaning. However I've once removed the flow restrictor as this was making the boiler squeal like crazy. You may also have a partial blocked plate heat exchanger too. Your gas safe guy shouldn't need to remove the gas valve to access it tho. The pumps removal does help.