Add radiators to old system

[Ianc2003]

I have a 1940 house with an old one pipe heating system that heats hot water and radiators together. Adding an single floor utility extension I am adding two extra radiators to the system. One large vertical radiator in the utility and a towel rail radiator in an on suite. these ate teed off from a newish copper pipe radiator in a bathroom. After the installation these new radiators are not-getting very warm, the large vertical radiator no warmth at all.
what needs to be done to heat up these new rads? Is there some form of balancing required? My plumber is not a heating engineer, but is competent. A new boiler was installed in 2009, prior to us moving in in 2017.
doi stick with this system or bite the bullet and ins a new system. The house also has a solar heating panel on the roof to provide hot water when the sun shines! Gas bill is reasonable so there is no benefit energy use wise.
appreciate any advice.

 

[Deleted member 120897]

It does sound like a balancing issue, although I’m not convinced you have one pipe system. You mentioned a new boiler, so why I think the latter. What size is the pipe tee’d off?

 

[Ianc2003]

It does sound like a balancing issue, although I’m not convinced you have one pipe system. You mentioned a new boiler, so why I think the latter. What size is the pipe tee’d off?

Thanks for the reply, the system has a large, 1.75” cast iron pipe running round the rooms with cast iron flat radiators spanning the pipe. The new radiators are attached with 15mm and 22mm pipes.

 

[SJB060685]

Could be a balancing issue, could be a pump problem, could be your old boiler is now undersized.
Old one pipe systems are a thing of the past and cause problems like this. That's not to say they don't work but more often than not they're either troublesome, or the engineer working on them doesn't have much experience with them.
How you approach this is entirely up to you but redoing the whole system (if you can afford it) would be beneficial.

 

[exedon2]

Pictures and a sketch of your pipework layout would be useful .
If it is one pipe you really have to know what your doing to extend the loop.

 

[Ianc2003]

Pictures and a sketch of your pipework layout would be useful .
If it is one pipe you really have to know what your doing to extend the loop.

Thanks for the advice looks like I will need to employ an experienced heating engineer

 

[cjg]

you have to feed in but long tail out, you do need some one who knows how really its very hard to try to explain. no elbows etc.

 

[Last Plumber]

If it is a one pipe (sounds like it is), then the connections will need to be made properly. You can't just tee in anywhere and expect it to work, especially not with narrow rads. You do need an old timer to look at it. There aren't many left but if it helps, the further apart the connections in the pipework, the better it will probably be, presuming the main pumped circulation pipes run below the rad. Not seen it obviously.