Blockages in 10mm plastic central heating pipes

[JonJ]

Our house was built in 2007 and we are the second family to live here - moving in in 2017. The central heating has been working fine - although the gas boiler is perhaps nearing the end of its life. But the boiler is not our current issue.

Last winter two of the radiators did not heat up and another radiator heats up very slowly. Hot water from the boiler for heating goes to a manifold and there is a manifold for the return. From the manifolds there are 10mm plastic pipes to and from each radiator.

On each problem radiator I have identified whether the blockage is on the flow or return by turning off the valves each end and unscrewing the pushfit elbows to see whether water escapes or not. I bought a very long length of flexible curtain wire and my attempt to unblock each radiator has been:
1. turn off the rad valve and lockshield
2. undo the elbow at the offending end of the radiator
3. pull off the pushfit elbow
4. push in as long a length of flexible curtain wire as I can

This has resulted in a little "crud" coming out of the radiator flow (or return) pipe, but only a dribble of water. Reconnecting the pushfit elbow and opening the rad valve and lockshield again tells me that I haven't solved the problem. The radiator still doesn't get hot.

Does anyone have any other DIY suggestions, or is it time to call in a professional to flush the pipes?

Thank you in advance for any help.

 

[terryplumb]

As long as all radiators heat up to some degree it would be worthwhile adding a chemical cleanser into the system ,such as X400. Do you have a magnetic filter on the system ,it would be a good idea to fit one if you don't.

 

[JonJ]

Two of the radiators don't heat up at all and a chemical cleaner WAS added to the system about 3 years ago by the plumber who did the annual service to the boiler.
Yes.... there is a magnetic filter on the system. But you have made me think, because I don't know if the filter has ever been cleaned out. I can understand how that would help to prevent a blockage, but I don't see how that will help once a pipe is blocked.

 

[terryplumb]

Was it a cleanser ,or an inhibitor that was add years ago ?
If there is no flow through all rads, cleanser will do nowt
Do the problem rads have Thermostatic rad valves fitted ? If so ,are they passing water through ( not stuck closed internally ) ?

 

[JonJ]

Was it a cleanser ,or an inhibitor - not sure which, but the boiler is due for a service in November so I will ask the engineer if I don't get our problem solved by then.

Do the problem rads have Thermostatic rad valves fitted ? All our radiators have a TRV and I have already checked that they are not stuck closed on the problem radiators.