Since we moved into our house the huge rad in the living room has never worked/never warms up much!!!!! I thought maybe the valves are faulty or the rad is clogged with dirt.... Took the rad off its clean, and the valves work, but this is where im a little confused.... We have a combi boiler and my assumption was that the heating system in a house works like a pump i.e. in from one side and out the other, the confusing part with this rad is both the valves are throwing out hot water at pressure!!!

Is this meant to happen? because it seems like they are the same pressure so the water is not moving

Rad was there when house was bought..

Is it not because the system is pressurised that you are getting water pumping out both ends?

Are the valves not marked with a direction arrow??

I shal think of more questions

D

Have you closed off the other rads and left this one open to see what happens then?

Pressure in the system should be around 1.5 to 2 bar. Have you traced the pipes back to see if they have been crossed? also have you vented it properly, it may be you have an air lock in the system. The pumps for these are usually located within the boiler.

You could try closing both valves, then open the bleed valve at the top and slowly open the inlet valve until the rad is full and then open the return valve but not fully.

@ Devil the valves are not marked

@WB I have not tried that, but what should i expect if i did?

@Fatboy I cant tell where the pipes go they come from the roof and go back into the roof, and the room ontop has laminate flooring so i am unable to lift the floor panels, how do i vent it properly? System was installed before we got here, How do i tell if there is an air lock? All other radiators in the house are working properly....

I tried closing valves, bleeding and opening inlet and slightly opening the return but it is still cold

I would close one rad at a time to try and shift a possible airlock from the cold one you have, always have one left open though and remove the rad stat so it cannot close

is there a thermostatic valve on the rad or just two ordinary valves?
as said before, turn off all the other rads to see what happens.

What pressure have you got showing on the combi boiler??

You say the pipes come from the room above is the boiler upstairs or on the same level as the faulty radiator? We have a similar problem where pipes go into loft then back down to a room so it always airlocks in loft so have to bleed it using bleed valves fitted in the loft.

issue may be the supply to your non working rad is T eed off another rad upstairs rather than off the main flow and return from boiler
try turning off the rad upstairs to "encourage" the flow down.

Another solution may be balancing the system , turn off all the other rads except the faulty one and see if it gets hot , then open the others in turn.

Thanks for all your help, I will get an update tomorrow

Wb the boiler is showing 1.5bar (british gas man said leave it there)
Derekl The dodgy rad is on the ground floor, the combi is on the 1st floor, all the rads on the ground floor either seem to go into the floor or upstairs in the 1st floor, but its only this one causing issues