Radiators doing my head in!?!?!?!

[panda2006]

Hi guys need help to cut a long story short, our house is running a 1 pipe feed system where all radiators are fed off a 22mm pipe, now until i switched all rads off for the summer (TRV's) they where working fine, now weather is cold turned all rads back on and out of 7 rads only 2 are working properly!!!
one of the non working has hot water to the trv, but the rad is not getting hot, and before you ask it has been bled, but seems to keep getting air in, now most the other rads none of the pipes are even hot either side of the radiator, its baffling me because i am usaully on top of my system and can fix most things myself, i have bled the pump that pumps the water around the rads, have bled all the rads in turn starting furthest from boiler but still no avail.
Last week i had to replace my hot water cylinder after a burst fitting, and it emptied the f&e tank when it burst, could refilling this have caused a blockage in my pipe feed to rads?????.
There is definitely hot water getting around the system because the other end of the house runs off another pump, and all those rads get hot. (live in a bungalow)
any suggestions of help would be handy its doing my nut in!!!!!!!

 

[kevplumb]

first are the trv's stuck



if not and it is air try turning pump speed up and close the ones that are working

 

[panda2006]

have tested all the trvs loosened pins etc, have tried turning all rads off, i am guessing i may have a blockage in the 22mm feed pipe would i be right in guessing this???? pump is on 3 anyhow.

 

[picasso]

when did you install the trvs?,

 

[panda2006]

some are about three years old some about 5

 

[picasso]

the reason for the question on your trvs is on 1 pipe systems low resistance trvs are needed, if you have fitted normal ones this may be part of the problem, but as you say it all worked before maybe not!

 

[panda2006]

yeah it all worked fine before no problem.
It seems no of the rads up the other end work now could it be a blockage????

 

[dal5band]

Usual method is to turn one radiator on at a time, with all the others off - that gets the full pressure going through the one radiator and clears any minor debris.

How does your one pipe system work ? Is each raditor connected to the same 22mm pipe at both ends in which case there is no pressure through the radiator as the pipe bypasses the radiator ? I this case you are relying purely on convection through the radiator and the slightest blockage will stop the flow.

 

[panda2006]

yeah both pipes connected to radiator, would i need to take rads off and clean then?????

 

[panda2006]

have tried turning rads off one at a time!!!

 

[kevplumb]

yeah both pipes connected to radiator, would i need to take rads off and clean then?????

what are they connected to at the other end tho

How does your one pipe system work ? Is each raditor connected to the same 22mm pipe at both ends in which case there is no pressure through the radiator as the pipe bypasses the radiator ? I this case you are relying purely on convection through the radiator and the slightest blockage will stop the flow.

err that IS how a one pipe system works

 

[doitall]

have tried turning rads off one at a time!!!

That won't work anyway.

You could turn the other pump off, and test if the pipe loop is getting hot, if it is you need to flush the rads out.

 

[panda2006]

Hi guys just ran the one pump this afternoon, and after turning one rad on at a time i can get that rad hot, but only at the top of the rad, then if i turn that one off and move to the next rad it does the same slowly gets warm at top and cold at bottom. The feed pipe is baking hot and the return pipe barely warm, will taking rads off and flushing fix this??

 

[doitall]

Most likely.