i need help

[jhnnegus]

I have just hung a new rad on the other side of the room to replace an old one. I connected the pipework to the rad that was on the other side of the wall and after testing for leaks filled the system and turned on the boiler.Now all the upstairs rads work and some of the downstairs, BUT the pipework for the rads that i have been working on go into the loft right across the other end of the loft and down to these rads.It is hot half way across the loft then cools down before it even gets to the end of the loft.
Can anyone tell me where i am going wrong.

 

[seco services]

sounds like trapped air in the loft pipes work.
your pipes go up then across then down, air rises it won't go back down so gets stuck at the highest point.
should of fitted two thumb bleed valves to the highest point.

 

[jhnnegus]

but these were there originally and it worked then and there are 2 thumb bleed valves where the pipes enter the loft.At its highest point.

 

[seco services]

it worked before because it had no air in the pipes.
you have just drained the system an refilled it.
depending on the lenght of pipe the airlock may be right down the other end.
i bet the bleed valves are in the hot section of pipe as the air will be in the cold.

 

[jhnnegus]

yes it is in the hot section of the pipe. How do I resolve this situation? There must be an easier way than putting bleed valves in. Thank you.

 

[seco services]

you could try shutting your other rads ( if the system is balanced count the number of turns that you shut each valve) an turning the pump on to full speed.

 

[jhnnegus]

So if I turn all the upstairs radiators off, and the other downstairs ones, should that be enough to get some heat to the other two? As regards to the pump, how many speeds are there? Thanks.

 

[seco services]

useally 3.
is it an open vented system?

 

[ChrisR]

Yes, or we wouldn't have suggested it, and,

had a look at the pump??

 

[jhnnegus]

How can I tell if the pump is working? wouldn't hot water rise so far anyway, without the use of a pump? Thanks.

 

[seco services]

useally you can feel them slighley vibrate.
or turn the speed up/down useally gives it away.
or remove the centre nut.

 

[jhnnegus]

Thanks for the advice. I'll give it a try.

 

[gigz]

but these were there originally and it worked then and there are 2 thumb bleed valves where the pipes enter the loft.At its highest point.

Might be a daft question but have you opened these to let the air out ?