Lockshield valve hot, Radiator cold

[terryplumb]

ok but closing off the TRV on the lounge rad doesnt do anything it stays hot, so should I close off the lockshield on this one?

Yes ,just make a note of how many turns it takes to close the lockshield,so you can return it back to its original setting later.

 

[wardr77]

Did that, still no change. Time to get the professionals in I think.

Thanks for you help much appreciated

 

[terryplumb]

Up to you. Why not drain and remove one rad .Then see if both valves allow water to flow when opened and check the rad for blockage. Could be a simple fix ?

 

[wardr77]

Ok will do that at the weekend, and see what happens will report back. Thanks again

 

[sircerebus666]

Also flush the rad out whilst it's off to give it a clean

Have you tried hitting the trv body with two hammers to shock it and get the water flowing , at least you with know what needs replacing ( do the lickshield too)

 

[wardr77]

Just to report back. Took the rad off today, took into garden and blasted it out with hose, there was some gunk in there, some black stuff, but not loads and after a couple of blasts with the hose water came out clean. The rad is a double panel rad with two bleed valves, one of which was corroded and managed to free that up and get it moving again. I then with bucket in hand opened up the TRV valve and a load of brown cruddy water shot into the bucket and then did the same on the lockshield side with same result, I did that a couple of times and the water seemed to come through cleaner. I did have all other rads switched off at the lockvalve and had the boiler running just to blast it through, not sure if this was a good thing to do, but only did it for a few seconds on each valve and kept clear of the hot water. After that switched CH off and reattached rad, turned on both valves and bled the radiator, put the CH back on and hey presto rad hot, this also seemed to fix the second rad which wasn't working so that was good.
To be honest I am not sure what fixed the problem, although the water was a bit cruddy it wasn't that bad. I am wondering whether it was the second bleed valve that was corroded, I couldn't bleed from that one when I first looked at the problem only the first one...
Anyway thanks to all for your help on this, particularly terryplumb

 

[sircerebus666]

Probably that crud was blocking the water through the rad , did you put inhibitor in when you refilled and repressurised the heating system?

 

[terryplumb]

You should consider adding cleanser to your system .After giving it time to work ,drain the system ,flush through ,then add inhibitor.
If the system is fed from a small f&e tank in the loft ,clean that out before draining out,if it's got cruddy water in the tank.
Glad your sorted by the way.

 

[wardr77]

No I didn't put cleanser or inhibitor in, though I guess I should probably do this. I was thinking about getting someone in to perform a powerflush of the system, not sure how much that costs, or if its just better to drain the system myself as you suggest?

 

[terryplumb]

What size pipes ( diameter) go to each rad ? If microbore ,10 mm or less ,powerflushing is a waste of time ,and a good few hundred quid !!
Is system tank fed or pressurised ?

 

[wardr77]

The pipes look standard 15mm to me. I'm really not sure about the system, been in the house since Feb and no manuals for the CH. Just had another look around the boiler and found a small label which says 'Greenstar F8 30CDI Regular ERP 7731600102' (Needed my missus's glasses to read that). Does this give any clue as to whether its a pressurised system?

Thanks again.

 

[terryplumb]

The boiler is FS 30cdi ,not F8.
Anyway it can be fed from the small tank in loft ,or sealed and pressurised. You need to take a look at the loft tank ,if it's still full of water and connected to a water supply , that's what feeds the central heating system.
The megaflo is sealed and pressurised and provides you with DHW (hot tap water).