partial one pipe central heating

[rob7475]

Hi,

We had our boiler and some radiators replaced last year. The plumber had to change some pipework as we were on a one pipe system so all of the radiators weren't getting hot.

Everything is working fine, but I want to replace the radiators that are in the living room. Currently, we have old skirting radiators in there which do get hot but don't give enough heat to keep the room warm when it's cold. I've bought a new radiator to install but plan to put it on a different wall so I'll need to run pipework to it.

I've had a look in the cellar to figure out how the pipes run to the current skirting radiators and I can only find one pipe in 15mm which branches off a 22mm. There are two 22mm pipes for flow and return so it won't be a problem running new pipes for the new radiator, but my question is, how is it possible for the skirting radiators to work when there is only one pipe running to them? Surely, they still need to connect to both flow and return? The 15mm branch pipe does have a valve on it with a red handle, not sure if that's any clue to how it's working or not?

I'm just worried, that I'm going to disconnect the old radiators and stop the central heating working because i've created a gap in the circuit?

Cheers

Rob

 

[dcawkwell]

If it is a flow and return there isn't a problem with cutting it.
It has probably been working via gravity if only running from
one pipe.

 

[rob7475]

If it is a flow and return there isn't a problem with cutting it.
It has probably been working via gravity if only running from
one pipe.

So it is possible for flow and return to run off one pipe to two rads? If that's the case, i won't have a problem. The central heating was a gravity system when we moved in. Changed to combi boiler now though but those two rads still work.

Cheers
Rob

 

[doitall]

There has to be a flow and a return connection even on a one pipe loop.

Skirting heating would go in one end and exit the other.

 

[rob7475]

There has to be a flow and a return connection even on a one pipe loop.

Skirting heating would go in one end and exit the other.

There is two pipes going into the radiators, but from what I can see (cellar only gives access to part of house as it is on a hill) both pipes must go back to the one pipe that branches off either the flow or return pipe of the CH.

 

[doitall]

You miss understand me.

The skirting heating is a one pipe loop.

Draw a straight line, and connect the start to the flow and the other end where ever it be to the return.