UK diy (uk.d-i-y) For the discussion of all topics related to diy (do-it-yourself) in the UK. All levels of experience and proficency are welcome to join in to ask questions or offer solutions.

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1   Report Post  
TheScullster
 
Posts: n/a
Default Plastic CH Pipe - How Close to Boiler

Hi all

I am getting very slow heat up of rads to an extension over the garage
(my/our bedroom as it turns out).
Tried turning down all the lockshields to encourage flow upstairs etc.
But, to get any real heat at all to these, the lock shields have to be so
closed down that the heat up time generally is ridiculous and the rads don't
get warm over their entire surface.
So, I believe that the supply to the upstairs (15mm) is undersize for the
number/size of rads, pipe lengths etc.- 6 rads single convector (average 1m
long 600 high) and 1 towel rail 500 wide x 1800 high approx.
The system is S plan and if I turn the pump speed up, I get pump over.
Maybe it's easier to pump over than overcome the throttled down valves and
the smaller 15mm piping.

So the question is - should I go plastic for the larger 22mm pipe and
replace existing copper?
If so, I understand that this shouldn't go right up to the boiler. If not
how close?

Thanks for any comments on above.

Phil


  #2   Report Post  
Christian McArdle
 
Posts: n/a
Default

The system is S plan and if I turn the pump speed up, I get pump over.

What is the boiler? You might want to consider switching to sealed
pressurised operation, which eliminates pump over and allows higher pump
speeds.

So the question is - should I go plastic for the larger 22mm pipe and
replace existing copper?


Probably. You may find you need to fix the pumping over at high pump speeds
even then. However, 15mm does sound very marginal for the load and 22mm is
probably more realistic.

If so, I understand that this shouldn't go right up to the boiler. If not
how close?


2-3m or so, although you should specifically check the instructions of both
the boiler and the pipe manufacturer and use the largest figure you find in
either. It's more of an issue on older non-condensing boilers.

Christian.


  #3   Report Post  
 
Posts: n/a
Default


TheScullster wrote:
Hi all

I am getting very slow heat up of rads to an extension over the garage
(my/our bedroom as it turns out).
Tried turning down all the lockshields to encourage flow upstairs etc.
But, to get any real heat at all to these, the lock shields have to be so
closed down that the heat up time generally is ridiculous and the rads don't
get warm over their entire surface.
So, I believe that the supply to the upstairs (15mm) is undersize for the
number/size of rads, pipe lengths etc.- 6 rads single convector (average 1m
long 600 high) and 1 towel rail 500 wide x 1800 high approx.
The system is S plan and if I turn the pump speed up, I get pump over.
Maybe it's easier to pump over than overcome the throttled down valves and
the smaller 15mm piping.

So the question is - should I go plastic for the larger 22mm pipe and
replace existing copper?
If so, I understand that this shouldn't go right up to the boiler. If not
how close?

Thanks for any comments on above.

Phil


On my 17KW oil boiler the install instructions said not to use plastic
within 1 metre of the boiler.

The figures I have for pipe sizing says 22mm is used for 5.5-11KW of
heat. 15mm would be for 2.1-5.5KW. So you need to add up the heat
output for your radiators you are feeding with that pipe. I know too
big a pipe means the water runs too slowly and you can sludge up the
pipes. I don't have the details to hand for that right now.

Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Earth Bondng Adrian Simpson UK diy 8 March 22nd 04 12:58 AM
Copper pipe sizing. Is bigger better? Paul J Home Repair 19 February 29th 04 08:52 PM
Near death boiler + replacing a boiler David Hearn UK diy 9 January 26th 04 01:44 PM
Another heating problem question! David Hearn UK diy 9 December 12th 03 09:29 PM
Ground to Gas Pipe?? w_tom Home Repair 4 June 23rd 03 10:14 AM


All times are GMT +1. The time now is 11:33 AM.

Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 DIYbanter.
The comments are property of their posters.
 

About Us

"It's about DIY & home improvement"