Heat not getting to the radiators?

[Ady]

Hi all

I am struggling getting our central heating going and hope I might be able to pick your brains. We have a Baxi Platimum Combi 28 He boiler. The pressure is fine and the boiler is firing up and supplying plenty of hot water with plenty of pressure. The outlet pipe from the boiler leads to a junction box which goes to all the radiators via microbore tubing and this and the pipes are getting red hot. Have checked all the radiator valves and they are ok and have even replaced some just to make sure. Have bled all the radiators numerous times for a long time and am only getting water coming through. I have checked the boiler pump and it is not seized or burnt out and is rotating fine. For some reason the hot water is just not flowing around the system? It is a bungalow we live in.

Any ideas?

 

[Riley]

If it’s microbore then I call blockage or circulation issue. Really need a gas safe engineer to be checking things on your boiler

 

[SimonG]

Disconnect rads at both ends and dump valves into bucket.

 

[Phil Redmond]

I had exactly the same with 2 radiators and worked out that it takes very little hot water to make the valve feel hot but good flow to get the rad hot.
If you drain some water off the rad and keep the lock shield end closed when you try and refill you will see it will take forever.
I found a good video on YouTube how to clear a blocked radiator pipe,
Closed off all the other radiators at both ends, drained the bad radiator and moved it out of the way, connected a pipe to the inlet side and gave it a few pumps with a foot pump holding the pump down at the bottom of each stroke and watching the pressure gauge on the pump dropping slowly then a few sharp blasts and pipe over bucket and eventually it cleared, put a bit of clean water in at the boiler and let it run through.
Worked a treat