I have a radiator with a sluggish flow pipe (checked by looking at flow
from radiator drain when opening either flow or return and seeing a vast
difference)

Based on a previous problem I suspectthe outlet from the manifold to be
choked with scale and or debris.

The manifold is rather "busy" and in a tricky location. I don't want to
just go in randomly disturbing joints.

Any ideas for identifying which union it might be. I can possibly eliminate
some from the direction - but want to identigy the problem one.

I had previously had a radiator re-piped (during some building work) due to
the same problem - but the blockage was only at the manifold - the pipe was
clean. Unfortunately I wasn't home when it was being done.

John wrote:

Any ideas for identifying which union it might be.

turn all rads off except the tricky one, see which pipe from the
manifold has (at least some) flow warming it?

On Mon, 02 Dec 2019 09:53:42 GMT, John wrote:

The manifold is rather "busy" and in a tricky location. I don't want to
just go in randomly disturbing joints.

Any ideas for identifying which union it might be. I can possibly
eliminate some from the direction - but want to identigy the problem
one.

Let the system go cold. Shut control (not lock sheild) valves on all
but the poor performing radiator. Turn system on, monitor pipe temps.
The one that warms first is the flow to the dodgy rad one a bit
cooler the return. Helps if you have an IR thermometer. Re-open the
control valves.

--
Cheers
Dave.

On Mon, 02 Dec 2019 10:01:32 +0000 (GMT), Dave Liquorice wrote:

Let the system go cold. Shut control (not lock sheild) valves on all
but the poor performing radiator. Turn system on, monitor pipe temps.
The one that warms first is the flow to the dodgy rad one a bit
cooler the return. Helps if you have an IR thermometer. Re-open the
control valves.

Oh and this may flush the crud to somewhere else where it's not a
problem. IR camera could replace IR thermometer. Lo res modules can
be had for £40 for use with a Pi or similar.

--
Cheers
Dave.

"Dave Liquorice" wrote in
idual.net:

On Mon, 02 Dec 2019 09:53:42 GMT, John wrote:

The manifold is rather "busy" and in a tricky location. I don't want to
just go in randomly disturbing joints.

Any ideas for identifying which union it might be. I can possibly
eliminate some from the direction - but want to identigy the problem
one.

Let the system go cold. Shut control (not lock sheild) valves on all
but the poor performing radiator. Turn system on, monitor pipe temps.
The one that warms first is the flow to the dodgy rad one a bit
cooler the return. Helps if you have an IR thermometer. Re-open the
control valves.


Thanks - just concerned that limited access might mean that conduction
through the copper pipe from the manifold may confuse things.

John Wrote in message:
"Dave Liquorice" wrote in
idual.net:

On Mon, 02 Dec 2019 09:53:42 GMT, John wrote:

The manifold is rather "busy" and in a tricky location. I don't want to
just go in randomly disturbing joints.

Any ideas for identifying which union it might be. I can possibly
eliminate some from the direction - but want to identigy the problem
one.

Let the system go cold. Shut control (not lock sheild) valves on all
but the poor performing radiator. Turn system on, monitor pipe temps.
The one that warms first is the flow to the dodgy rad one a bit
cooler the return. Helps if you have an IR thermometer. Re-open the
control valves.


Thanks - just concerned that limited access might mean that conduction
through the copper pipe from the manifold may confuse things.


You can try for nought?
--
Jimk


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

If the distance and pipe id permit try rodding with a flexible curtain wire

Cynic wrote in
:

If the distance and pipe id permit try rodding with a flexible curtain
wire

I reckon about 15 feet. At the radiator end there are 2 90 degree bends.

Had tried back flusing with mains water when the system was empty.

On 02/12/2019 12:42, John wrote:
Cynic wrote in
:

If the distance and pipe id permit try rodding with a flexible curtain
wire

I reckon about 15 feet. At the radiator end there are 2 90 degree bends.

Had tried back flusing with mains water when the system was empty.

Cut the pipe, rod out and rejoin?

SteveW

Have you considered an airlock these commonly occur on re-filling after a drain down especially on a system with drop feeds to radiators.

Richard

Tricky Dicky wrote in
:

Have you considered an airlock these commonly occur on re-filling
after a drain down especially on a system with drop feeds to
radiators.

Richard


Over the years I have tried many things - including back flushing. Evidence
from another union leads me to suspect a blockage - possibly due to a burr
on the pipe.

Steve Walker wrote in news:qs40ul$ad4$3@dont-
email.me:

On 02/12/2019 12:42, John wrote:
Cynic wrote in
:

If the distance and pipe id permit try rodding with a flexible curtain
wire

I reckon about 15 feet. At the radiator end there are 2 90 degree bends.

Had tried back flusing with mains water when the system was empty.

Cut the pipe, rod out and rejoin?

SteveW



Good idea - if the pipe can be identified - and if there is room to do
it.Lots of bent pipes and limited space.