K3 1600x600

[johnwa]

Hi all I have fitted the radiator the back and center panel are even heat but the front one is cooler at the bottom, I was told it was a flow problem but it is the only live radiator on my system the rest have been turned off, the boiler is a new Valliant 24 KW and the system had a power flush
I have changed the radiator but the problem is the same.
Any ideas guys?

 

[gas112]

what size pipework is supplying it , both valves fully open

 

[johnwa]

Hi thanks for replying 15mm pipework I have run with the valves open and various turns on the lock shield, the straight run to the rad from the boiler is app 10m, I had a K2 installed before with no problem I just needed a bit more heat, is a booster pump the answer if I ned more flow?

 

[Johntheo5]

This "cold" panel seems to be a feature of the K3, someone on one of these sites increased the pump head to give a constant 6M on a heat only boiler which largely solved the problem but it seems a shame to have to run with this head as most systems do fine at a pump head of 3 to 3.5M, also your Vaillant can only run at a maximum head of 4.0M (400 mbar), the default setting might be as low as 2.0M so check the following D parameters, D.170, D.171, D.172, D.173, D.174 & D.175.

 

[johnwa]

Hi John thanks I have checked and it is on 400mbar also there is a motor speed adjustment for when you need a bit more flow, I have screwed it as per installation manual and I have a more uniform heat on the outside panel. So I may fit an external pump to save the internal pump working harder.

 

[Johntheo5]

What do/did the flow/return temps D.40&D.41 read with the K3 on its own?
Have you any particular pump in mind for boosting and how do you propose to stop/start it?