Is my central heating under powered?

[dirtbiker100]

Have recently bought my first house - an ex-council house. And it has microbores (8mm) feeding all the radiators in the house. Which is ok for most as they come off a 15mm pipe fairly close (1-2m away) to the rads themselves. But my main bedroom and lounge are fed off one microbore pipe.

The drawing below might show better detail but the feed pipe comes from the boiler in 22mm, splits into two 15mm pipes. The one i'm concerned about splits again into two 8mm microbore pipes. One way goes 1-2m into a small bedroom (2.75m x 2.4m) rad and the other way travels 3.6m where it splits off into a large bedroom (3.5m x 3.5m) rad while the rest carries straight on to the corner of the room down the lounge wall (2.35m high) and along into a rad big enough to heat the lounge – 6.5m x 3.5m.

Total distance travelled since leaving the 15mm = 8.35m in which it needs to heat the bedroom and the lounge. total btu needed is around 15000 btu

Do I need to change it to 15mm in order for both rooms to be heated sufficiently? I have cavity wall and plenty of loft insulation too.
Some have said that the long microbore pipes will not heat the rooms comfortably while my dad who is helping with DIY seems adamant that it's fine.
I shall be swapping the rads around as they currently stand in the drawing. lounge will have 600x1600 double and bedroom the 600x1800 single.

Anyone have any ideas?

http://img.photobucket.com/albums/v514/Anoobis/9_0069.png

 

[kevplumb]

i would change it to 15

and give the system a good clean while you are at it

what boiler have you got

make / model

 

[dirtbiker100]

Boiler has been replaced (last month) with a worcester bosch greenstar 30cdi. 4 years old and removed from a friends house who gave it to me for free.
The guy who replaced my boiler strongly mentioned the 8mm and rads but my dad who is helping a lot (so i need to be careful in my approach here to keep the free labour) thinks it would be a large outlay for not much benefit. The same guy put inhibitor in the system etc and balanced the rads although i'm not sure to what degree.

 

[electronicsuk]

Do the radiators that are tee'd off the microbore get as hot as those that are on their own microbore circuit? Are the rooms adequately heated? If the answer is yes, there is no need to change anything. As others have said, making sure the system is properly cleaned and inhibited will help prevent future problems and blockages.

 

[tryitandsee]

You haven't mentioned any TVR's.

For the price of three TVR's, I would put them on the bedroom rads, being that the bedrooms I think should be cooler. So when they shut down when bedroom's up to temperature, all the flow will then concentrate on your rad in the lounge where you need it most. It also allows you to restrict the flow to these bedroom rads, making for 'easy' balancing adjustments.

Whatever, don't upset the old man, as they don't get much better than that

 

[dirtbiker100]

Ah forgot to mention tvr's. They're on most of the rad's in the house so it seems like after swapping the rad's round to make them more suitable for the rooms i'll see how i get on long term. Currently the lounge takes a long time to heat up but thats down to the rad being far too small. Yep definately want to keep dad happy! Thanks