One cold radiator

[daytona1uk]

Hi,
One of my downstairs radiators won't heat up. Please could someone help me diagnose the problem? Here are some facts:
1. The whole system is 10 years old.
2. The radiator in question does *not* have a TRV.
3. I have a Gloworm Ultimate boiler.
4. There is a hot water tank upstairs.
5. When I open the bleed valve on the radiator water comes out. No air comes out.
6. If I close either valve at the end of the radiator and drain some water through the bleed valve then eventually the pipes warm up.
7. I have tried turning off all the other radiators and turning the pump to maximum, but to no avail.
8. Last winter the radiator heated up without any problems.
I would be grateful for any ideas - run out of things to try
Thanks,
Graham

 

[Slugbabydotcom]

Try taking the rad off and sticking a hose pipe on each valve in turn to flush some water and hopefully any airlock or blockage through it.

 

[JohnD]

Has it ever been cleaned and inhibited

what colour is the water that bleeds out

what sludge is in the F&E tank in the loft

I suspect you have a sludge blockage.

If you are lucky, when you take the rad off, you will find a 3/4" bsp connector (as used for garden hoses and washing machine hoses) fits on.

You might find that no water comes out of one of the valves meaning that one is either seized or has a blockage.

Sadly chemical cleaners are not much good at cleaning a blockage out of a sludgy system, because the blockage prevents the chemical from flowing down the pipe towards it.

If you find black water, and sludge in the bottom of the rad when you take it off, that encourages me to believe that is the cause.

edited: You say " If I close either valve at the end of the radiator and drain some water through the bleed valve then eventually the pipes warm up." so this means there is some water flowing; so if it is sludge, a chemical cleaner (and preferably also a Magnaclean) should shift it.

 

[bengasman]

sounds like a typical case of a soiled system. measure ph, if under 7, you need a flush

 

[Terrywookfit]

sounds like a typical case of a soiled system. measure ph, if under 7, you need a flush

I use a T D S tester !!!

What if fill water is ph of less than 7

Apart from that it is usually obvious if a system is in need of a flush due to all the ****e in it!!!

 

[daytona1uk]

Hi - All fixed! I took the radiator off and flushed it with clean water. Also I drained each pipe for a while (bsp connector tip v.useful!). Radiator heats up without any problems now. Lots of gurgling from one of the pipes so I guess there was an air lock in there somewhere.

By the way, the water from the radiator was like a very watery oil - very black. No solids came out though.

Also, I had added inhibitor to the system about 2 months ago when I added TRVs to some of the upstairs radiators.

Thanks for all the help,
Graham

 

[JohnD]

the water from the radiator was like a very watery oil - very black.

If you can afford £100 or so and an afternoons work to fit it, a Magnaclean will be very useful at trapping all that circulating black sediment, which will do nothing but harm and as well as wearing out the pump and collecting in your boiler, will probably cause more blockages in future.

 

[bengasman]

i have seen more than one system where all the gunk had solidified at the bottom of the rads and in the pipes; the water came out crystal clear from the drain cock so the tds meter would show perfect. if the ph is under 7, in other words the system is acidic, you can bet your bottom dollar that there is a lot of sediment stuck somewhere. add limescale in hard water areas and you have a recipe for disaster.
where do you get a decent tds meter from? no supplier in my area does one.