NO CIRCULATION THROUGH RADS

[pete26671]

Hi i am having trouble with my ch sys i have now drained the sys down twice but an unable to get circulation around the rads. i get no heat to any rads but if i undo a drain off on one of the rads it does get hot but then goes cold after retightening please help [/u][/b]

 

[namsag]

Go for the basics is your pump working .

 

[pete26671]

yes pump is ok as it is only 3 months old

 

[rssteve]

yes pump is ok as it is only 3 months old

some pumps which are 1 day old are faulty. Just because its making a noise does not mean its running.

 

[namsag]

Ok so do you have a motorised valve and is that opening
Absolute basic is making sure there is no air in pipework around the pump by bleeding the pump

 

[sambotc]

Airlock?

What sort of system is it? open vent with tank in loft or sealed system with filling loop?

Did the problem start after draining it down for whatever reason or have you drained simply because you had no flow before?

Sam

 

[pete26671]

yes have done all the basic stuff but to no avail im afraid

 

[pete26671]

open vented

 

[pete26671]

i drained down to change a rad from an old panel rad to a towel rail

 

[sambotc]

More than likely air i would say. Have you checked for airvents on the top of the boiler? Also have you got a vent on the flow to the cylinder? (presuming you have a cylinder)

Are you getting any heat up the flow pipe off the boiler towards the cylinder if you have one?

Is your boiler making any noise? What is the boilers make and model?

Also can you explain how your system is made up (2 or 3 port valves, is it microbore pipework how high the f&e tank is above the highest point etc)

Sam

 

[pete26671]

i am getting heat on both flow and return pipe but nothing in the rads themselves all the rad valves are open but nothing.the boiler is a myson economist about 21yrs old.its all piped with 15mm and 22mm pipe with 3 port valve

 

[spacethegas]

do you have h/w.
did you manually open the diverter when you filled & vented.

 

[pete26671]

yes have h/w but cant understand why no c/h and no did not open diverter manually as dont know what the diverter looks like sorry

 

[pete26671]

would a backflush work ???

 

[spacethegas]

diverter is 3 port valve.
there is normally a lever you can slide across and locate to a manually open position.