The system has a one year old condensing boiler, and is a conventional 3
port
valve job for CH and hot water cylinder. There is a roomstat and all except
one of the radiators have a thermostatic valve. The original system was
installed in the late sixties.

Some weeks ago I removed some radiators as part of a kitchen/diner
refurbishment. Today I drained the system down, added a couple of pipes
in preparation for new radiators to be fitted after the plasterer comes next
week. After refilling I am unable to get any heat from the radiators.

It's as if there is a blockage on the return side. The flow side gets hot
but
the radiators stay cold. The only things that get hot are the bathroom towel
rails - they are connected between the pump and the 3 port valve. All the
radiators have been bled. What can possibly be wrong? An air lock?
Wouldn't the pump just pump it round? Or perhaps a real blockage in the
return somewhere?

Whilst fitting the pipes today I noticed quite a bit of crud in the 22mm
return pipe. Not enough to block it though...

http://www.gillandroy.com/diy/pipe

This surprised me. When the boiler was fitted 12 months ago the
plumbers spent many hours flushing the system. I'll definitely flush
the system myself in a few weeks when I have some time spare.

Any thoughts, cos it's a bit nippy :-)

Thanks,
Roy

RzB wrote:
The system has a one year old condensing boiler, and is a conventional 3
port
valve job for CH and hot water cylinder. There is a roomstat and all except
one of the radiators have a thermostatic valve. The original system was
installed in the late sixties.

Some weeks ago I removed some radiators as part of a kitchen/diner
refurbishment. Today I drained the system down, added a couple of pipes
in preparation for new radiators to be fitted after the plasterer comes next
week. After refilling I am unable to get any heat from the radiators.

It's as if there is a blockage on the return side. The flow side gets hot
but
the radiators stay cold. The only things that get hot are the bathroom towel
rails - they are connected between the pump and the 3 port valve. All the
radiators have been bled. What can possibly be wrong? An air lock?
Wouldn't the pump just pump it round? Or perhaps a real blockage in the
return somewhere?

Whilst fitting the pipes today I noticed quite a bit of crud in the 22mm
return pipe. Not enough to block it though...

http://www.gillandroy.com/diy/pipe

This surprised me. When the boiler was fitted 12 months ago the
plumbers spent many hours flushing the system. I'll definitely flush
the system myself in a few weeks when I have some time spare.

Any thoughts, cos it's a bit nippy :-)

Thanks,
Roy

if you heating enginner did it properly it would have flushed it then
put in a inhebitor

do i understand your a diy er with a £800 flushing maching kicking
around

it sounds like you may have an air lock--which is not just a matter of
bleeding rads

any yes the boiler may have been fitted 12 months ago--to old
pipework/rads??
and then you messed with it

is your hot water working ?
the best way to get rid of air lock if first concentrate getting hot
water going--the lock all rads down bar the nearest one,,get that going
then move on to the next turn off the one you got going

some times there is a bypass valve--turn it off as you are doing this
and make sure hot water is off











RzB wrote:
The system has a one year old condensing boiler, and is a conventional 3
port
valve job for CH and hot water cylinder. There is a roomstat and all except
one of the radiators have a thermostatic valve. The original system was
installed in the late sixties.

Some weeks ago I removed some radiators as part of a kitchen/diner
refurbishment. Today I drained the system down, added a couple of pipes
in preparation for new radiators to be fitted after the plasterer comes next
week. After refilling I am unable to get any heat from the radiators.

It's as if there is a blockage on the return side. The flow side gets hot
but
the radiators stay cold. The only things that get hot are the bathroom towel
rails - they are connected between the pump and the 3 port valve. All the
radiators have been bled. What can possibly be wrong? An air lock?
Wouldn't the pump just pump it round? Or perhaps a real blockage in the
return somewhere?

Whilst fitting the pipes today I noticed quite a bit of crud in the 22mm
return pipe. Not enough to block it though...

http://www.gillandroy.com/diy/pipe

This surprised me. When the boiler was fitted 12 months ago the
plumbers spent many hours flushing the system. I'll definitely flush
the system myself in a few weeks when I have some time spare.

Any thoughts, cos it's a bit nippy :-)

Thanks,
Roy

"marcusb3495" wrote in message
roups.com...
if you heating enginner did it properly it would have flushed it then
put in a inhebitor

Yes - they did that. It's been without inhibitor for about a month..
since I removed radiators..

do i understand your a diy er with a £800 flushing maching kicking
around

I am a DIY'er - the local plumbing shop have a rental flushing machine.

it sounds like you may have an air lock--which is not just a matter of
bleeding rads

hmm.. I imagined the pump would push the air into the rads..

any yes the boiler may have been fitted 12 months ago--to old
pipework/rads??
and then you messed with it

Yep - correct. Old pipework, new boiler and I messed with it:-)

is your hot water working ?

Hot water just fine.

the best way to get rid of air lock if first concentrate getting hot
water going--the lock all rads down bar the nearest one,,get that going
then move on to the next turn off the one you got going

Ok - that makes sense - I'll do that.

some times there is a bypass valve--turn it off as you are doing this
and make sure hot water is off

Don't think I have a bypass valve. Are the towel rails performing a
sort of bypass function? Or is that summat different?

I put the original post up at 19:44 and then had to go out. I left the
system running while I was out. On my return a few minutes ago
(22:45) all the upstairs radiators are hot (with one exception).
The downstairs rads are still cold. So it looks like summat has shifted.
I'll do as you suggest and see if I can get the downstairs rads running
as well.

Many thanks for your help,
Roy

"RzB" wrote in message
...
The system has a one year old condensing boiler, and is a conventional 3
port
valve job for CH and hot water cylinder. There is a roomstat and all
except
one of the radiators have a thermostatic valve. The original system was
installed in the late sixties.

Some weeks ago I removed some radiators as part of a kitchen/diner
refurbishment. Today I drained the system down, added a couple of pipes
in preparation for new radiators to be fitted after the plasterer comes
next
week. After refilling I am unable to get any heat from the radiators.

It's as if there is a blockage on the return side. The flow side gets hot
but
the radiators stay cold. The only things that get hot are the bathroom
towel
rails - they are connected between the pump and the 3 port valve. All the
radiators have been bled. What can possibly be wrong? An air lock?
Wouldn't the pump just pump it round? Or perhaps a real blockage in the
return somewhere?

Whilst fitting the pipes today I noticed quite a bit of crud in the 22mm
return pipe. Not enough to block it though...

http://www.gillandroy.com/diy/pipe

This surprised me. When the boiler was fitted 12 months ago the
plumbers spent many hours flushing the system. I'll definitely flush
the system myself in a few weeks when I have some time spare.

Any thoughts, cos it's a bit nippy :-)

Thanks,
Roy


OK - just to close this thread neatly..

My problems were down to a dicky pump. It finally failed
completely over the weekend.

I have installed a new pump and all my problems are fixed!

One thing might be of help to others searching... When the pump
failed the boiler stopped with an F5 Overheat Fault error code.
(Glo-Worm hxi). The overheat thermostat needs to be reset
before the system will run again. I should have realised
this but didn't think it through. I was a bit dismayed when
the system didn't run having changed the pump!

On the Glo-Worm hxi the overheat thermostat is behind
two covers.

All OK now though - yipee!

Thanks,
Roy