Fitting two radiators in series

[Ivorr211]

Hi,

At the back of the kitchen is a small extension lobby with the door to the back yard. Off the lobby is the downstairs toilet. The floor is concrete and quarry tiled throughout. The central heating system pipes are 8mm.

In the lobby is a small radiator with the pipes feeding it coming up from the floor. Because of a step down to the lobby there is very little pipe showing on the outgoing side of the radiator and it is almost inaccessible. The incoming pipe has about 6" between the radiator and the floor. The radiator is 550mm wide and 700mm tall.

There is no radiator in the toilet and I would like to fit one. I have the practical ability to do this, but I was wondering whether it would be feasible to connect the two rads in series instead of parallel. I don't think it is going to be possible to tee off the outgoing pipe of the lobby radiator and there is no access to the pipes below floor level.

I would be really grateful for advice please.

 

[footprints]

In theory yes, it is often done in bay windows three rads instead of a bent one, but don't expect too much from an 8mm supply. Very much a "suck it and see" situation.
Of course turning off one rad will turn off the other too!

 

[Whitespirit66]

Rads in series will always be a compromise. 8mm microbore can carry roughly 4 to 5 kw - so if you're only talking about two smallish single panel rads, the pipe will cope with the load.

However, in these situations, the rad out of the two that receives the flow from the boiler last will always be noticeably cooler than the first rad. With 8mm pipe rather than 15mm, this may be even more noticeable.

 

[AlanE]

On pumped system feed to one radiator with return from the other.

One end of each radiator will have no connections. On these ends join two bottoms together and two tops together possibly best in 15mm.

Piping this way will effectively create a single radiator equal in length to the two singles but more importantly will make the heating of both more even and efficient.

Piping them so say only the bottom connections are joined will mean the water will flow into first, give up some heat, and then the flow into the second will be at this lower temperature.

 

[Ivorr211]

Thank-you all for your replies. It is very much appreciated.