Worcester Bosch 30 Si crackly noise

[puma]

Hi, I wonder if anyone can help me with an issue that has arisen with my Worcester Bosch 30 Si boiler. A few days ago I drained the system to replace a faulty TRV, and with the boiler flow valve shut off I used the integrated filling loop to flush the system, then refilled with added inhibitor.

Pressure on the system seems fine and the CH appears to be working correctly, however I have noticed an issue with the DHW. About 15 to 20 seconds after shutting off the hot water tap, there is a crackly/hissy noise coming from the area where I understand the secondary (DHW) heat exchanger is located. This lasts for a few seconds and ends immediatley upon a clunking noise (which I presume is the diverter valve shutting?). The crackling/hissing doesn't seem to happen if the CH is running, and is much less apparent if the flow rate of the hot water is higher. I have also noticed that the water from the tap seems to now be a bit hotter than previously, and it seems hotter at higher flow rates now too.

Thanks for reading - can anyone offer any advice?

Edit: Having listend a bit more intently I wonder if what I can hear is actually the pump? Is it possible that there is some air of debris trapped in it?

 

[SimonJohns]

It sounds to me like you may need a repair

It's going to involve getting a gas safe registered engineer around and having them do some work for you

I would also suggest that you have your system protected by something like a magnaclean or tf1

 

[Howsie]

Have you opened up the boiler? Time for a GSR engineer I think.

 

[Dotty]

We cannot and will not give advice on the installation or repair of boilers, cookers or ANY gas appliances for your own safety.

Please go to Gas Safe Register | Ensure your gas engineer is registered. or post a thread in the 'I'm looking for a plumber / gas engineer' section of these forums remembering to include your location. [DLMURL="http://www.ukplumbersforums.co.uk/im-looking-plumber-gas-engineer/"]I'm looking for a Plumber or Gas Engineer[/DLMURL]

If you are gsr please increase your post count to 10+ then send a PM (Private Message) with your gsr details to either Gas man - http://www.ukplumbersforums.co.uk/users/8668/ or Redsaw - http://www.ukplumbersforums.co.uk/users/2718/ who will check you and then give you access to the gsr private forum.

Providing gas-related advice to anybody who should not be touching gas and cannot prove their competetence is unacceptable. We will take whatever action we deem appropriate to prevent such advice being given


Thank you.