Central heating radiators and hot water not heating up

[krembo]

Hi
The radiators of the central heating system are heating only the lowest few inches. This happens mainly upstairs.
I drained air out of them using the square screw till a bit of water went out and they heat up.
The day after that we had the same issue and did the same thing and this continues ever since for like 2 weeks.
Today I decided to get this over with and drain air till its all gone so I drained every radiator at least 5 times and still they are going cold after some time.
Btw - not sure it has anything to do with it - the hot water boiler we heat using electricity because the central heating wouldn't heat it.
Thanks in advance,
Jacob

[htg engineer]

Boiler make and model ?

if you're continuously having to bleed the radiators then there's either air being drawn into the system, or water being lost from the system (leak).

More info on boiler make and model/system type please.

htg

[krembo]

Thanks for the reply.

Its a CRANE CAVALIER 45 MARK III.

Can you please tell me how can I find the leak? I see no water on the floor/carpet anywhere so is it inside a wall?
I went up the roof to look at the tank there and the only tank I saw was full but I'm not sure its the right one.

[krembo]

Thanks for the reply.

The model is CRANE CAVALIER 45 MARK III.

I climed into the roof today and saw one tank of water. It was open at the top and full of water. Water was dripping from the incoming pipe that is open above the tank.

Can you please tell me how to find the leak? I see no water on the floor or carpet anywhere. Does it mean the leak is inside a wall?

Thanks,
Jacob

[krembo]

More details - hope this sheds some light.

When CH is turned off, all water from upstairs radiators flow out immediately and fast - I can hear the air air bubbling into the radiators. After a few minutes their are almost empty.
None of that happens with the radiators downstairs.

Thanks,
Jacob