Hi,
I've just replaced an ancient 500mm high radiator in an upstairs bedroom with a new 1800mm tall vertical radiator, but I've run into as problem in that I don't think I have enough head of water to completely purge the air out of the radiator.
To explain...My boiler is not a combi type, and the heating system has a header tank in the loft. The bedroom is also located in the loft. I believe the water in the header tank is well above the bottom of the new rad but lower than the top of the rad.
I have to bleed the radiator with the pump off as the pump is on the return to the boiler and so just sucks air into the radiator if the pump is running.When I bled it with the pump off, some air came out of the radiator, but then stopped venting air and no water came out. I'm assuming this is because the water in the rad had reached the same height as the water in the header tank?
From measurements,of the relative heights, I estimate the radiator should be 3/4 full. However when I run the heating, none of the radiator gets hot - I was hoping it would be hot up to the level of water The only thing that gets hot is the pipe connected to one of the radiator valves.
Can anyone please advise:
1. The vertical radiator has two horizontal tubes, one across the top and one across the bottom, and lots of vertical tubes running between them. With this design, does the radiator have to be full of water to get any flow of water within the radiator, or should it work (with less than 100% efficiency) if only 3/4 full?
2. I've read that some vertical rads have flow valves within them to improve their efficiency. Not sure if mine has one, but if it did, does this mean that water will not flow in the rad if the input and return pipes were to be connected the wrong way round?
3. Its been suggested I could loosen the rad valves and tip the radiator down so as to drop the level below the header tank level, then bleed the rad and return it to the vertical. If I did that, would the pump increase the pressure in the system enough to make water flow, or would it still be limited by the tank head pressure?
Any help gratefully received before I bite the bullet and buy a less tall replacement radiator.
Regards
Dave
I've just replaced an ancient 500mm high radiator in an upstairs bedroom with a new 1800mm tall vertical radiator, but I've run into as problem in that I don't think I have enough head of water to completely purge the air out of the radiator.
To explain...My boiler is not a combi type, and the heating system has a header tank in the loft. The bedroom is also located in the loft. I believe the water in the header tank is well above the bottom of the new rad but lower than the top of the rad.
I have to bleed the radiator with the pump off as the pump is on the return to the boiler and so just sucks air into the radiator if the pump is running.When I bled it with the pump off, some air came out of the radiator, but then stopped venting air and no water came out. I'm assuming this is because the water in the rad had reached the same height as the water in the header tank?
From measurements,of the relative heights, I estimate the radiator should be 3/4 full. However when I run the heating, none of the radiator gets hot - I was hoping it would be hot up to the level of water The only thing that gets hot is the pipe connected to one of the radiator valves.
Can anyone please advise:
1. The vertical radiator has two horizontal tubes, one across the top and one across the bottom, and lots of vertical tubes running between them. With this design, does the radiator have to be full of water to get any flow of water within the radiator, or should it work (with less than 100% efficiency) if only 3/4 full?
2. I've read that some vertical rads have flow valves within them to improve their efficiency. Not sure if mine has one, but if it did, does this mean that water will not flow in the rad if the input and return pipes were to be connected the wrong way round?
3. Its been suggested I could loosen the rad valves and tip the radiator down so as to drop the level below the header tank level, then bleed the rad and return it to the vertical. If I did that, would the pump increase the pressure in the system enough to make water flow, or would it still be limited by the tank head pressure?
Any help gratefully received before I bite the bullet and buy a less tall replacement radiator.
Regards
Dave