MegaSack DRAW - This year's winner is user - rgwb
We will be in touch
Can you help. This is the picture. I need to replace some 'missing' rads that are part of a functioning but in need of repair CH system.
There are two missing.
One has the remnants of the old valves still attached and not sealed in anyway.
The other has a sealed off pipe ( I assume water is flowing to it?) and the other end is the remnants of another valve, also un sealed.
Question is how do I tell the direction of flow if I fit new rads? I assume rads have an input and output?
The system works, and is controlled by a standard room stat, though they need constant bleeding.
I am very competent with normal plumbing building DIY etc. I can make solder joints and have a good selection of tools, though I've never attacked CH
I assume I just need to establish which end the water flows into, and fit standard valves that end?
Radiators aren't direction, some thermostatic valves are, but just use ones which aren't and you'll be fine. You normally fit two valves, an isolation / flow restriction valve at on end and a thermostatic valve at the other.
[img] 
[/img]
Well that would make the whole thing easy.
So a bi directional thermostatic valve can be fitted at either the flow in or out end?
So a bi directional thermostatic valve can be fitted at either the flow in or out end?
Yep. The uni-directional ones have an arrow on the body for the flow direction.
http://www.screwfix.com/p/pegler-terrier-ii-white-chrome-trv-connector-15mm-angled/23130
White and chrome finish. Offers frost protection. Positive shut-off. Approved to EN 215.
Wax Sensor
Bi-Directional Valve Body
Connector or Elbow Option
Double O Ring Seal
5 Year Manufacturer's Guarantee
And for the other end (for balancing the system):
http://www.screwfix.com/p/verona-angled-radiator-valves-15mm-pair/37800
Chrome-plated brass finish. Positive shut off.
Bi-Directional Valve Body
High Quality Chrome-Plated Brass