Alpha 280e whining CH not DHW

[debaj]

I have an Alpha 280e. When first turned on after about 10 mins it emits a loud continuous whining. This lasts for 2-3 mins then stops. It only happens when CH is on, not DHW. The expanssion vessel was recharged last year, and the sound seems to be coming from that area, could it be linked as it only happens when the boiler is first running, and so as the pressure in the system increases. Any help would be greatly appreciated.

 

[b13kal]

Sounds like a fan?

Have you opened it?

I would call a gas safe engineer

 

[debaj]

Have taken the cover off just to determine if the sound was coming from the fan. It isn't. Pressures are fine, 1 bar when cold and 2 bar when running. It only happens during the initial warm up which is why I was wondering about the EV.

 

[ianmcd]

Most common on this boiler is the diverter valve shuttles easy to test when the heating is on and it is making the noise open a hot water tap and if it stops when you open the HW tap then it is the diverter valve shuttles

 

[debaj]

Thanks Ian, I'll try this tomorrow when it fires up from cold.

 

[debaj]

Hi Ian,
yep you're right. Stops the whining even if you only turn it on briefly without it switching to supplying HW. Can these be serviced as I looked for the valve assembly and at £250 it might just have to be one we have to get used to. Is it an easy job if it can be done, or can it be done as part of a service?

 

[ianmcd]

No you dont need a complete valve you can buy a service kit but they are removed and re-fitted from the back of the valve can be a bit of a pain in the erse , you can do it yourself no need to be Gas Safe registered but be patient as it can be a bit of a job, an hour at most I would say but keep the kids out of ears reach as a lot of swearing ha ha