Pathetic water pressure

[Bagpuss12]

I've lived in my house for 2 years and always had to tolerate a pathetic flow of hot water. The cold is fast and powerful but the hot is just like a fast trickle! Surely it's the same pressure coming in so presumably something is happening with the boiler which is a Main Combi 24? Any ideas?

 

[Gigas]

Blockage in boiler or probably the cold iso valve is closed too much. It is usuall closed slightly to regulate the flow through the boiler.

 

[Bagpuss12]

Is this ISO valve something I can adjust or would it affect the workings of the boiler? The boiler had been serviced annually since we moved in so I would have thought a blockage would've been picked up on?

 

[Gigas]

Look under the boiler, toward the right hand side there should be a blue handle. Is it in line with the pipe or diagonally?

 

[Bagpuss12]

On the pipes under the boiler there is a red stop valve, the valve that allows me to increase pressure and 3 further valves that are all black! Can't see anything that's blue?

 

[Gigas]

Ok sorry the cold one will be the 2nd black handle from the right side. Is it straight or diagonal?

 

[Bagpuss12]

It's running parallel in line with the pipe as are the others?

 

[Gigas]

Well that's the easy 1 done. Probably best to get engineer in now.

 

[Agile]

You need to be scientific.

First thing is to measure the hot flow rate. Should be a maximum of about 9 litres per minute.

If much less then ask the engineer servicing about it and get him to identify the cause and rectify.

Tony