New radiator issues

First do you have a magnetic filter fitted to the system, if not I would have one fitted, Magnaclean are among the best, will will collect all the crud (iron oxide).
Fitted a filter here, was cleaning it out several times a week for a couple of weeks to start with, now it is checked once or twice a year & cleaned as needed.
Secondly a cheaper option is put a bottle of Sentinnel X800 cleaner in the system & let it run around for a couple of weeks, with heating fully on you should notice a improvemt within hours.then drain down flush a couple of times & refill, then you can add Senntinel X900 Filter Aid & X100 Inhibitor to the system.
You could also take radiators off & take them outside side & flush them through with hose.

http://www.plumbingforless.co.uk/he...gnaclean-professional2-filter-22mm-cp10300022

https://www.sentinelprotects.com/uk...systems/sentinel-x800-jetflo-ultimate-cleaner

https://www.sentinelprotects.com/uk...tral-heating-systems/sentinel-x900-filter-aid

https://www.sentinelprotects.com/uk...ntral-heating-systems/sentinel-x100-inhibitor

 

Chrisp.

Did you fit new valves too? Is one of them a TRV? And is it either 'bi' or else fitted correctly to the 'flow' side?

Is you system pressurised or vented - do you have a wee expansion tank in t'loft?

Anyhoo, if there's any chance of sludge running around your system, then KIAB's advice is sound - start collecting it using a magnetic filter. (And if there isn't any sludge, then fit one anyway...)

Fit a filter first, so anything else you do which could dislodge sludge won't cause harm.

Ok, something you can try that won't cause a problem; fully shut off both valves on that rad, and disconnect them from the rad. Obviously the rad will drain - so be prepared...

If possible, then fully remove the rad and try flushing it out chust to see if any gunk has ended up in there since being fitted. You don't need to fully remove the rad provided you can access the open ends of the disconnected valves, but it's probably easier if you do.

Ok, now get a pan/bucket and towels - open each valve fully, just one at a time, and allow it to flow in to your container for a good number of seconds - at least 20. Observe the colour of the water and if sludge comes out (and also observe chust how good/poor the flow is).

If the water is coming out nicely but looks dark, then simply keep it running until it noticeably clears. Then shut that valve and repeat on t'other.

If you have a pressurised system (eg combi), then the pressure will drop after a few seconds and the flow will stop, so in this case turn on the boiler's filling loop fully (repeat that 5 times after a drink...) to allow water to continue to flow.

Ok - if water flows well out of each valve, then you clearly don't have a blockage. So I'd say the chances were that a valve wasn't opening properly.

Try that - and report back, please.

When refilling the rad, open the bleed screw and only one valve to refill. When bled, open t'other.

 

Did you turn off all the other rads and leave the new one on so as to force the hot water through? Then balance the system?

 

As above - it may be just balancing problem or TRV that is not bi directional and wrong way round. You can flush it chemically yourself to start with.

Anyway - new to the forum, Hi everyone!

 

Hi Bort!