newly replaced rads are cold? :S

[obseen16]

hi all. i just replaced 3 rads in my folks home. the system is a 1 pipe system (never seen a 1 pipe system before) trouble is i removed 3 old rads 35yrs old if not older. anyway after replacing them one gets hot but the other 2 are barely luke warm. one pipe is hot but the other is cold and the rads aint getting hotter. could this just be a balancing problem? the old ones worked fine.

got me puzzled a bit.
all the pipework has remained the same no alterations just new rads and valves.

hope someone can help

cheers
J

 

[Mobileghod]

all valves on?
the rads that are warm turn off one side then go check the cold ones, bleed pump bleed rads

could be a right game getting it going but best way to do it

 

[sonray ltd]

its a one pipe system, poss air lock or sludge.
turn the pump up to full speed.

 

[billybongo]

Sometimes when you drain old systems the pumps never seem the same or pack up completely , might be worth having a close look at the pump.

 

[red man walking]

shut off lockshield on the hot rad and the lockshield on any other hot radiator ( i assume there are more than 3 rads in the house). When the new rads get warm, bleed em and then introduce other rads gradually.
I would say it is defo a balancing problem. Water will always take the easy route,

 

[obseen16]

thanks guys. great advice,

i thought it might be more likely to be a balancing problem so after writing the first post i did go and shut off the other valves in the house. thanks for the advice it was really helpful and nice to know i was on the right tracks lol.

many thanks (once again)

James.

 

[Phil]

Don't forget one pipe systems benefit from 'full bore' rad valves.