One cold radiator but both pipes are also cold

[TheRunningMan]

Hi.

All the radiators in my house are hot except for one of them which is cold and both connected pipes are also cold. From the information I have gathered from the forum and other sources it seems there may be a blockage stopping the water getting to this one rad. Does this sound right?

If so, is the correct method to unblock it to turn all the other radiators off, forcing all the water to the one radiator and hopefully removing the blockage? Will I run the risk of the blockage transferring to a different part of the pipework?

Anthony

 

[Armo74]

Yes, try turning off all other rads to force it through first.

 

[TheRunningMan]

Yes, try turning off all other rads to force it through first.

Can this be done while the radiators are still hot or shall I let them cool first?

Also I have a radiator that looks like it has a lockshield valve at both ends (both ends are without caps). Will this have any issues with the working of the rad/system? How do I know which one to turn off? Is it usually always the right for example that feeds the radiator and the left that takes the flow away?

 

[Armo74]

Do it with the rads on. As for the rad with 2 lockshields feel which pipe gets hot first and turn that one off

 

[TheRunningMan]

Do it with the rads on. As for the rad with 2 lockshields feel which pipe gets hot first and turn that one off

Cheers. I'll give that a go

 

[TheRunningMan]

So I've turned all the radiators off at the flow valves (left the lock shields open) and set the system running. The offending radiator including flow pipe is still cold but the return pipe seems to have warned up slightly. Does this sound right?

What would be the next step from here. Chemical flush (if so which one) or a power flush?

 

[Burnerman]

Do you feel confident about turning both valves fully off, disconnecting the radiator and removing it for a wash through with a hose pipe?
At the same time, opening each valve in turn will let you see which pipe is blocked.
John

 

[TheRunningMan]

Do you feel confident about turning both valves fully off, disconnecting the radiator and removing it for a wash through with a hose pipe?
At the same time, opening each valve in turn will let you see which pipe is blocked.
John

Hi John.

Yes I can do that no problem. I've had a look at the radiator manifold (If thats even whats its called) and the four pipes coming off the main flow pipe that go in the direction of my cold radiator are hot. As one of these must go to the cold radiator and the flow pipe that connects to the cold radiator is still cold do you think there could be a blockage somewhere in that pipe? Only issue is that the flow pipe to the radiator is encased into the wall.

The top of the photo seems to be the flow pipe and the return at the bottom

View media item 55730
I'll get the radiator off now and have a look

 

[Burnerman]

Yes, you are certainly on the right track......do make sure that the header tank continues to fill, and the amount of black gunge in the rad may give you some sort of hint as to how dirty the system is.
John

 

[TheRunningMan]

The good news is its not a blocked pipe Glad I did what you said and took the radiator off first. When I opened the feed valve, hot water came shooting out

This is the colour of the water that came out. Guessing I need some inhibitor in the system

View media item 55735
When I add the Inhibitor. What steps should I follow?

1. Drain down the system (Tying up the ball in the tank in the loft)
2. Fill again which fresh water and drain again.
3. Repeat step 2 until water runs clear
4. Add inhibitor and re-fill system for one last time.

Now to try and flush the radiator.

 

[Burnerman]

In the interim - maybe there's a power flush in the future - theres nothing to stop you letting the header tank keep filling as you drain the old water out which should eventually run clean.
Naturally you wont cleanse the whole system this way but if you allow water out from each valve it will remove some gunge from that line.
As for the inhibitor, I use Fernox F1 concentrate injected into the (cleaned) radiator, then I'd advise cleaning the header tank (with a wet vac) and when its empty, adding F1 liquid and then letting the tank refill.
Be lucky! Maybe its time for a thorough clean in the Spring - should there be one!
John