cold radiator

[John Paul]

HELLO,
I have one cold rad upstairs and i think it might be the last on the line,I took the rad off and cleaned it out,i then checked the for air locks but that does not seem to be the problem,the water flowing out of the pipe work is very slow even with the circulating pumb on, All the other rads are working fine. Its a two storey house and its a gravity fed system.Could the pumb be the problem? grateful for any help

Regards
John Paul

[htg engineer]

What size pipework? it could be a partial blockage, sometimes the washers in the radiator valves can dislodge - drain the system and remove the radiator valve - if they're really old you'd might as well replace them.

[John Paul]

Had the valves off but and they are fine,water wnot flowing as it should with the pump on

[htg engineer]

Check pump setting, if on 1 or 2 - try 3 to see if there's any improvement. it may be that the pump isn't as effective as it should be. If not better then there's a blockage/kink in the pipe work. Sometimes at installation if a pipe is kinked it can last for years but will gradually trap debri and restrict the flow - especially if 8mm or 10mm. Could also be a blockage in manifold - again if 8mm or 10mm.

[John Paul]

[quote="htg engineer"]Check pump setting, if on 1 or 2 - try 3 to see if there's any improvement. it may be that the pump isn't as effective as it should be. If not better then there's a blockage/kink in the pipe work. Sometimes at installation if a pipe is kinked it can last for years but will gradually trap debri and restrict the flow - especially if 8mm or 10mm. Could also be a blockage in manifold - again if 8mm or 10mm.[/quote]
switched pump setting and same result ,pipes are 13mm, would it help to drain the system after i put a cleaning solution in expansion a week before,or may be just pump not good enough now

[proptech]

How about running the system with all other radiators turned off. This may well dislodge any air or minor obstructions. Trying the water flow with the pump switched on can give a very misleading result.
Is it a poor flow on both ends of the rad ? If so, I would think any blockage will not be near the rad, but possibly where the cold feed enters the system. Try holding a magnet to this area of pipework, any blockage will be metalic in origin, and should be noticable.
If all other rads are getting hot, I would not suspect the pump.