Two cold radiators

[emailrob]

It seems cold radiators is a common problem on here.

My problem is that the pipes leading to two of my radiators is also cold. I have tried bleeding them, one of the downstairs ones came out with lots of black water.

Does this mean there is a blockage somewhere else in the system?
I have a combi upstairs (two story house). All the other radiators are burning hot, it's just the two downstairs ones I have a problem with.

Thanks for any help

 

[AnonymousImport]

Could be that the system needs balancing. Try turning most of the working radiators off and see if the cold ones warm up. Note that some systems need a bypass radiator to ensure the pump has a circuit (and avoid straining it), so if in doubt always leave at least one working radiator on.

If this has the desired effect, try adjusting the lock valve settings on all radiators. Generally the lock valves on the radiators nearest the boiler should be permanently turned further down than those further away. In the extreme case (my old house was an example) I've actually had all valves completely open and only the radiator nearest the boiler worked!

If you still can't get any heat from two radiators there's probably a blockage somewhere.

 

[emailrob]

Thanks mate, I'll give it a go tonight.