Cold radiators

[aky20]

Hi all,

I have a valliant eco pure 25kw system boiler, 210l valliant unvented tank and 12 radiators in a three story house.

The radiator in our loft extension on the second floor hardly gets warm, but the towel radiator in the en-suite literally 2 feet away is red hot. The radiator does not have a trv valve so the pin isn’t stuck.

The system has been bled and there is no air in the system. I have switched all of the trvs off then the radiator is red hot.

I have previously run x400 and x800 in the system on different occasions to clean the system out and have a magnetic filter fitted.

There is also another radiator close to the boiler that is always cold. The radiator has been changed along with the valves but this has made no difference. I suspect the pipe is blocked is there any way to unblock the pipe without having to pull the floor up to cut and replace pieces of pipe?

Thank you for any advice in advance!

 

[JohnD]

Turn off ALL the hot ones. Do some of the cold ones heat up?

 

[CBW]

Sounds like it needs balancing

 

[aky20]

Turn off ALL the hot ones. Do some of the cold ones heat up?

The radiator in the loft heats up after turning off the hot ones. The other one which is cold stayed cold.

 

[aky20]

Sounds like it needs balancing

Already tried this, when I cleaned the system out last year. Could it need rebalancing?

 

[JohnD]

The radiator in the loft heats up after turning off the hot ones. The other one which is cold stayed cold.

What happened when you turned off the loft one as well?

 

[aky20]

Already tried this, when I cleaned the system out last year. Could it need rebalancing?

The blocked one still stayed cold, so presume that confirms that the pipe is blocked?

Funnily enough the loft radiator seems to get hot even after opening all the trv's so maybe airlock in the pipe or displaced some sludge?

 

[JohnD]

The blocked one still stayed cold, so presume that confirms that the pipe is blocked?

Turn off the valves at each end, and release them from the radiator. Open one valve and run it into a bucket. Then close it and run the other. If one of them does not run it has an obstruction.