Boiler sounds like a cow

[applepie]

Hello, my hot water is set to come on at 5.30 am for 1 hour , for the last 2 days I have heard this noise as the boiler is in the airing cupboard next to my bedroom. It doesn't happen straight away.Today the hot water had been on 40 mins before starting, ysterday 55 mins. As far as I'm aware using the central heating does not cause the noise. The noise seems to start as the boiler fires up if that makes sense, and it stops after a minute
The boiler is a Baxi solo 30 HE A .
I am looking for an engineer but not sure where to start,Baxi do engineer visits starting at £369 which is a lot of money.
Can anyone listen and give me any idea what the problem is , many thanks

 

[Deleted member 120897]

Is the boiler in the wiring cupboard or the hot water cylinder? I would start to look at a motorised valve first, and anything else is it’s on a sealed system, so perhaps a heating engineer?

 

[applepie]

Is the boiler in the wiring cupboard or the hot water cylinder? I would start to look at a motorised valve first, and anything else is it’s on a sealed system, so perhaps a heating engineer?

@ChrisB1982 thanks for replying The boiler and hot water tank are in the airing cupboard which makes it difficult to access the boiler. Not sure what you meant about sealed system. There are two tanks in the loft one big one small. I am currently looking for an engineer. When you say motorised valve do you mean the one attatched to the hot water tank, because I have had problems with that too, sometimes when the heatings been on and after it's off it makes a continuous humming noise, the only way to stop it is to put the hot water on even just for 10 seconds.

 

[Deleted member 120897]

Not a sealed system with 2 tanks in loft, sealed systems use pressure and is sealed to atmosphere, bit like a Combi. Yes motorised valves are part of the pipework arrangement in the cylinder cupboard. Could be the pump, but that wouldn’t explain why it’s not doing it on heating mode.

 

[applepie]

Not a sealed system with 2 tanks in loft, sealed systems use pressure and is sealed to atmosphere, bit like a Combi. Yes motorised valves are part of the pipework arrangement in the cylinder cupboard. Could be the pump, but that wouldn’t explain why it’s not doing it on heating mode.

@ChrisB1982 Thanks again for replying and advice. I noticed the noise early in the morning because it is near where I sleep. It may yet happen when the heating is on but I may not be able to hear it downstairs, I think it's a good idea to get the motorised valve replaced, it's faulty anyway , it may even fix the bigger problem. ireally appreciate your time you are very kind, cheers

 

[Deleted member 120897]

No problem. Nice to be thanked and appreciated sometimes