Had a calamity the other day when we found that we had a leak in our
central heating system pipework.
In the excitement (!) to dig up the tiled bathroom floor we MAY have
managed to reverse the polarity of the two pipes concerned that feed
from the boiler.
Does it matter which way round the water flows through the system ?
Is the there any simple way to discover if I have them the wrong way
round ?
Thanks

In article .com,
Digby wrote:
Does it matter which way round the water flows through the system ?
Is the there any simple way to discover if I have them the wrong way
round ?

You should have an adjustable gate valve or TRV on rads usually fitted
on the flow side with a locksheild on the return. Check which pipe gets
hot from cold first at a rad. This will be the flow.

--
*The only difference between a rut and a grave is the depth.

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

In an earlier contribution to this discussion,
Digby wrote:

Had a calamity the other day when we found that we had a leak in our
central heating system pipework.
In the excitement (!) to dig up the tiled bathroom floor we MAY have
managed to reverse the polarity of the two pipes concerned that feed
from the boiler.
Does it matter which way round the water flows through the system ?
Is the there any simple way to discover if I have them the wrong way
round ?
Thanks

It matters if it flows the wrong way through the boiler! The boiler
thermostat is near the outlet pipe. If this point becomes the inlet instead,
the thermostat will sense the cooler return water instead of the just-heated
water - and the boiler will overheat.

The flow and return pipes on the boiler should be labelled. If not, you'll
have to refer to the installation manual. When correctly connected, the flow
pipe will be considerably hotter than the return pipe.
--
Cheers,
Roger
______
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monitored.. Messages sent to it may not be read for several weeks.
PLEASE REPLY TO NEWSGROUP!

In article ,
"Dave Plowman (News)" writes:
In article .com,
Digby wrote:
Does it matter which way round the water flows through the system ?
Is the there any simple way to discover if I have them the wrong way
round ?

You should have an adjustable gate valve or TRV on rads usually fitted
on the flow side with a locksheild on the return. Check which pipe gets
hot from cold first at a rad. This will be the flow.

Most TRV's for some years can be fitted on either end.
I usually fit on the return side, where the pipework
will be cooler and have less direct thermal effect on
the TRV sensor. So in short, I don't believe you can
use this method to tell which is flow and return.

3-port valves always go on the flow side AFAIK.

--
Andrew Gabriel

Thanks guys - all useful stuff !
To be a little more specific about my problem the problem occurred with
two 22mm plastic pipes that run up the wall in the hall. There was leak
where they joined other pipework under the bathroom floor above. Whilst
I took up the tiles in the bathroom to gain access, my wife chopped out
the two plastic pipes all the way down to the under the hall
connections with the idea that I would then replace the plastic with
copper. However in the fun of the moment we didn't pay enough attention
to which pipe from below the hall joined to which pipe above the hall
ceiling (in the bathroom floor).
I have completed all the pipework now, re-filled the system and am now
running it up.
Apart from a lot of airlocks it appears to be working OK but I am still
concerned that I may have reversed those joints. The boiler (which is
situated 30 yards from the plumbing incident ) is firing up alright and
the correct outlet pipe (ie the flow) is getting hot first.
Would this have happened if I had incorrectly joined the pipes ?
Thanks again for all this valuable help.

In article .com,
Digby wrote:
To be a little more specific about my problem the problem occurred with
two 22mm plastic pipes that run up the wall in the hall. There was leak
where they joined other pipework under the bathroom floor above. Whilst
I took up the tiles in the bathroom to gain access, my wife chopped out
the two plastic pipes all the way down to the under the hall
connections with the idea that I would then replace the plastic with
copper. However in the fun of the moment we didn't pay enough attention
to which pipe from below the hall joined to which pipe above the hall
ceiling (in the bathroom floor).

They're unlikely to cross over in this sort of run so I'd guess it would
be difficult to get them wrong.

--
*Cover me. I'm changing lanes.

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

In an earlier contribution to this discussion,
Digby wrote:

Thanks guys - all useful stuff !
To be a little more specific about my problem the problem occurred
with two 22mm plastic pipes that run up the wall in the hall. There
was leak where they joined other pipework under the bathroom floor
above. Whilst I took up the tiles in the bathroom to gain access, my
wife chopped out the two plastic pipes all the way down to the under
the hall connections with the idea that I would then replace the
plastic with copper. However in the fun of the moment we didn't pay
enough attention to which pipe from below the hall joined to which
pipe above the hall ceiling (in the bathroom floor).
I have completed all the pipework now, re-filled the system and am now
running it up.
Apart from a lot of airlocks it appears to be working OK but I am
still concerned that I may have reversed those joints. The boiler
(which is situated 30 yards from the plumbing incident ) is firing up
alright and the correct outlet pipe (ie the flow) is getting hot
first.
Would this have happened if I had incorrectly joined the pipes ?
Thanks again for all this valuable help.

It sounds as if you're probably ok.

The rest of the system probably doesn't care too much as long as the boiler
is the right way round. The only exception to this is that some TRVs are
noisy if the flow is in the wrong direction, and - for reasons which I don't
understand - Honeywell say that their 3-port valves *must* be in the flow
pipe.
--
Cheers,
Roger
______
Email address maintained for newsgroup use only, and not regularly
monitored.. Messages sent to it may not be read for several weeks.
PLEASE REPLY TO NEWSGROUP!