CENTRAL HEATING NOT WORKING

[CHOPSY01]

HI
I need HELP!!!
I have 6 radiators in my house. 2 downstairs and 4 upstairs. The one in the front room downstairs is fine and heats up well. The other downstairs radiator did work well until a couple of weeks ago and is now cold! I have a towel radiator in the bathroom which is very hot and another radiator (furtherest from boiler) in a front bedroom which is warm but not hot. the other 3 radiators are very cold. We have tried to remove air locks by turning off all the radiators except the one furthest away from bolier. The radiator got very hot at the top but was only luke warm at the bottom and as soon as I replaced the valve it cooled down.
We have had the system cleaned with a chemical cleaner and the valves checked.
Do we need a power flush? We have been advised that this is difficult as our radiators have flexi hose piping.
The radiators are only 4 years old - would they have corroded in this time? The water tank in the loft was very sludgy though could this be the problem?

Any advise is gratefully appreciated

 

[bobbo85]

turn the ones working off and then the ones not working turn off bar one if it heats up go to next rad that hasnt been ok and turn on and carry on like so,also the end with no trv ,lockshield valve when the rad is hot ,turn your non trv valve off and open it up just a bit about 2 -3 turns it needs balancing

 

[ChrisR]

SOunds exactly like sludge. New rads can rust right through in a few months.

 

[namsag]

You say rads are 4 year old but how old is the system and what sort of system Is it, fully pumped or gravity HW and pumped CH . Get rid of the flexi and get rads piped properly as you WILL get flooded in time otherwise

 

[bengasman]

Sounds like serious sludge build up, if you have an open vent system, you almost surely need a powerflush to solve the problem. a lot of people think it is a waste of money and that there are other ways of getting rid of sludge. Thought there are indeed other ways of getting rid of most of the sludge, nothing will do the job as thoroughly as a powerflush. Provided of course that it is done by someone who has the right equipment, AND knows how to use it. I thought there was not a lot of knowledge required for powerflushing but changed my mind about it after doing the course at kamco’s training centre. It is not rocket science, but there are quite a few tricks to get rid of sludge that has settled to hard block.
I remember the second one I did on a boiler swap. Owner was one of those people who knows things a lot better than those rip off plumbers and he assured me powerflushing was not necessary as he had already flushed the system himself. He did shut up when I showed him what came out at the dump. Not just deep dark black, mud.