My CH seems to have a problem. Over the last couple of days some of the
downstairs rads have taken ages (2 hrs +) to get hot, upstairs (and some
downstairs) hot in 10 mins. It is not a 'bleeding problem' and totatally
new, I have lived here for 10 years! I think I have a blockage somewhere in
the downstairs pipework. Before I pay somebody £300+ for a powerflush is
there any way I can do it my self? I am very confident in removing
radiators and draining down etc. but what is the procedure for 'power
flushing'? I have got a Karcher pressure washer but I think sticking that
in the header tank on full bore will not work!

John wrote:

My CH seems to have a problem. Over the last couple of days some of the
downstairs rads have taken ages (2 hrs +) to get hot, upstairs (and some
downstairs) hot in 10 mins.

Firstly check the pump - it may have failed, leaving you with only
gravity circulation, which will obviously strongly favour upstairs.
Remove the pump's bleed screw to expose (on most designs) the end of the
shaft. There is usually a screwdriver slot in this end which you can
use, with the power off, to see if the shaft is free to rotate, or
whether it has seized. Then with the power on and the aid of a torch,
see whether rotation can be observed.

If the pump isn't running it will usually need to be replaced, but
before doing so check for any electrical fault causing it not to receive
power.

HTH
--
Andy

In article ,
Andy Wade wrote:
My CH seems to have a problem. Over the last couple of days some of
the downstairs rads have taken ages (2 hrs +) to get hot, upstairs
(and some downstairs) hot in 10 mins.

Firstly check the pump - it may have failed, leaving you with only
gravity circulation, which will obviously strongly favour upstairs.

I'd say that amount of 'gravity circulation' would be rare to say the
least - otherwise you'd never be able to control the temperature with a
thermostat.

--
*For every action, there is an equal and opposite criticism *

Dave Plowman London SW
To e-mail, change noise into sound.

Dave Plowman (News) wrote:

I'd say that amount of 'gravity circulation' would be rare to say the
least

It's certainly something I've seen though, and is consistent with the
much faster circulation upstairs, compared to down.

- otherwise you'd never be able to control the temperature with a
thermostat.

A 'stat controlling only the pump? Quite antiquated, that, and often
associated with the upstairs rads getting hot when the heating is
supposed to be off, unless a vertical check valve is fitted.

Anyway we don't know much about the system in this case, and my point
was just that I'd check the pump first as it's so easy to do.

--
Andy

On 13 Dec, 00:20, "John" wrote:
My CH seems to have a problem. Over the last couple of days some of the
downstairs rads have taken ages (2 hrs +) to get hot, upstairs (and some
downstairs) hot in 10 mins. It is not a 'bleeding problem' and totatally
new, I have lived here for 10 years! I think I have a blockage somewhere in
the downstairs pipework. Before I pay somebody £300+ for a powerflush is
there any way I can do it my self? I am very confident in removing
radiators and draining down etc. but what is the procedure for 'power
flushing'? I have got a Karcher pressure washer but I think sticking that
in the header tank on full bore will not work!

Has anybody fiddled with the rad lockshield valves? It could be that
the system has gone out of balance with the water taking the path of
least resistance through the system and barely circulating through
some of the rads.

"Martin Pentreath" wrote in message
...
On 13 Dec, 00:20, "John" wrote:
My CH seems to have a problem. Over the last couple of days some of the
downstairs rads have taken ages (2 hrs +) to get hot, upstairs (and some
downstairs) hot in 10 mins. It is not a 'bleeding problem' and totatally
new, I have lived here for 10 years! I think I have a blockage somewhere
in
the downstairs pipework. Before I pay somebody £300+ for a powerflush is
there any way I can do it my self? I am very confident in removing
radiators and draining down etc. but what is the procedure for 'power
flushing'? I have got a Karcher pressure washer but I think sticking that
in the header tank on full bore will not work!

Has anybody fiddled with the rad lockshield valves? It could be that
the system has gone out of balance with the water taking the path of
least resistance through the system and barely circulating through
some of the rads.

Not that I am aware of.

Cheers

john

"John" wrote:
My CH seems to have a problem. Over the last couple of days some of the
downstairs rads have taken ages (2 hrs +) to get hot, upstairs (and some
downstairs) hot in 10 mins. It is not a 'bleeding problem' and totatally
new, I have lived here for 10 years! I think I have a blockage somewhere
in the downstairs pipework. Before I pay somebody £300+ for a powerflush
is there any way I can do it my self? I am very confident in removing
radiators and draining down etc. but what is the procedure for 'power
flushing'? I have got a Karcher pressure washer but I think sticking that
in the header tank on full bore will not work!

It depends on how bad the sludge is. You could try turning the upstairs
radiators off and see if that moves the sludge in the downstairs circuit
sufficient to let water circulate. If that doesn't work you could try
connecting hosepipes to the drainage valves (if they have been installed)
and letting cold water run through the system. That leaves removing the rads
and flushing them out, or hiring a power flushing machine - Google for how
to power flush central heating system. The Karcher idea is a non-starter
unless you use it to flush out rads that you have removed.

"John" wrote in message
...

"Martin Pentreath" wrote in message
...
On 13 Dec, 00:20, "John" wrote:
My CH seems to have a problem. Over the last couple of days some of the
downstairs rads have taken ages (2 hrs +) to get hot, upstairs (and some
downstairs) hot in 10 mins. It is not a 'bleeding problem' and totatally
new, I have lived here for 10 years! I think I have a blockage somewhere
in
the downstairs pipework. Before I pay somebody £300+ for a powerflush is
there any way I can do it my self? I am very confident in removing
radiators and draining down etc. but what is the procedure for 'power
flushing'? I have got a Karcher pressure washer but I think sticking
that
in the header tank on full bore will not work!

Has anybody fiddled with the rad lockshield valves? It could be that
the system has gone out of balance with the water taking the path of
least resistance through the system and barely circulating through
some of the rads.

Not that I am aware of.

Cheers

john

I would try a flushing liquid, such as Fernox or Sentinel. Drain the
heating system and refill adding the flusher to the header tank. Let it
circulate through the system for a few days or according to the
manufacturers instructions, then drain and refill. Drain again and flush
with water from the header tank to remove the flushing solution. Make sure
you completely fill the system at all stages by bleeding the radiators.
Finally fill the system, adding a good quality inhibitor, and bleed all the
radiators, preferably with the water hot and the pump off.

Has your system always contained inhibitor? If not, you could have
corrosion problems. The next plan would be to remove the offending
radiators, take them into the garden and use a hosepipe to back-flush - much
like a car cooling system. Remove the bleed screw and also the large screw
in plug from the top LHS of the radiator. You will need a suitable tool to
remove this - its like a large Allen key with a square fitting (obtainable
from sheds). You may need to use PTFE tape when replacing. If you're
confident with radiator removal, I certainly wouldn't waste £300 for a power
flush.

Terry D.

"Terry D" wrote in message
...

snip

.... Make sure you completely fill the system at all stages by bleeding
the radiators. Finally fill the system, adding a good quality inhibitor,
and bleed all the radiators, preferably with the water hot and the pump
off.

That's interesting. I've also bled with the pump on, so evidently been
doing it wrong :-( What is the reason, please?


--
Martin

"Martin" wrote in message
...

"Terry D" wrote in message
...

snip

.... Make sure you completely fill the system at all stages by bleeding
the radiators. Finally fill the system, adding a good quality inhibitor,
and bleed all the radiators, preferably with the water hot and the pump
off.

That's interesting. I've also bled with the pump on, so evidently been
doing it wrong :-( What is the reason, please?


--
Martin


According to my research, bleeding with the pump running can suck air into
the system. However, I find this difficult to believe - I have used both
methods in the past with complete success.

Terry D.

"Terry D" wrote in message
news

According to my research, bleeding with the pump running can suck air into
the system. However, I find this difficult to believe - I have used both
methods in the past with complete success.

I used to bleed with the pump running but then I started getting air in the
system and the gas man said that was the cause. I now always bleed without
the pump running and that cured it.

"Terry D" wrote in message
...

I would try a flushing liquid, such as Fernox or Sentinel. Drain the
heating system and refill adding the flusher to the header tank. Let it
circulate through the system for a few days or according to the
manufacturers instructions, then drain and refill. Drain again and flush
with water from the header tank to remove the flushing solution. Make
sure you completely fill the system at all stages by bleeding the
radiators. Finally fill the system, adding a good quality inhibitor, and
bleed all the radiators, preferably with the water hot and the pump off.

I did all this in Dec 2004 I assume the inhibitor will still have some life
left in it.

Has your system always contained inhibitor? If not, you could have
corrosion problems.

The house was built in 1992, we bought it in 1997 in the loft was an empty
bottle of inhibitor dated some time in 1997 so presumably the old owner did
it then.

The next plan would be to remove the offending radiators, take them into
the garden and use a hosepipe to back-flush - much like a car cooling
system. Remove the bleed screw and also the large screw in plug from the
top LHS of the radiator. You will need a suitable tool to remove this -
its like a large Allen key with a square fitting (obtainable from sheds).
You may need to use PTFE tape when replacing.

I do this every time I decorate a room while the rad(s) are off for
decorating purposes.

If you're confident with radiator removal, I certainly wouldn't waste £300
for a power flush.

I was thinking the same but was worried I could be wasting my time if the
blockage is in a pipe rather than a rad.

Cheers

John

"DIY" wrote in message ...

It depends on how bad the sludge is. You could try turning the upstairs
radiators off and see if that moves the sludge in the downstairs circuit
sufficient to let water circulate. If that doesn't work you could try
connecting hosepipes to the drainage valves (if they have been installed)
and letting cold water run through the system. That leaves removing the
rads and flushing them out, or hiring a power flushing machine - Google
for how to power flush central heating system. The Karcher idea is a
non-starter unless you use it to flush out rads that you have removed.

Thanks for the advice I will try turning the upstairs off and see if that
helps, problem is I now have to wait untill everything cools down. The
Karcher idea was actually a joke but I forgot the smiley ;-)

Cheers

John