Balanced system, still have problem - pipe run issue ?

[Loz]

Hi,

 

Recently posted on problem I had with a single radiator in new extension in this post and thought I had solved problems with suggestions on balancing system on this forum - thanks for help so far.

 

To re-cap we have an old 1950's house with 10mm pipework to the rads that are plumbed in parallel.  We recently added a two storey side extension which has pretty much broken us financially and mentally.  The house is all finished, plastered, tiled and painted and we have been having problems with the heating system (I wish I had spent more time testing before reaching this stage !).  As part of the works we had a new Baxi 800 series system boiler installed with 15mm pipework coming off the existing flow and returns (28mm copper) - although not exactly sure where they came off.  

 

So the main problem is that in our new bedroom the radiator has not been working.  If I turn off most of the rads in the house and with boiler pressure at 2.0 (baxi docs recommend 1.5) I can get that rad working and flow and return are correct way round for that rad.  I have been balancing and bleeding system to death for over a week and what I have found is that as I start to open lockshields even a tiny bit to get a rad to work at some point the problem radiator will stop or if it works another rad stops working.  Have done the balancing in order I think they now heat up after investigating and watched umpteem videos and  read tons of internet postings.

 

The root of the issue I believe is the pipework to the problem radiator, the picture below shows the pipework:

 

 

The pipes in question are the two coming up from floor in all white speedfit.  They go into a T-junction, the downward T runs about a metre to a towel radiator in bathroom (the studs are an ensuite)  then the other two pipes run upwards to the attic, from here another small rad is T-d off down a wall and back up and that rad doesn't really work either but the main issue is then those pipes carry on up to the top of a vaulted ceiling, and then back down to the floor level seen in pictures, it is one hell of an up and down run and just don't think the pump/flow has enough gumption to get water up, over, down, round the rad and back up.  Looking at it now not sure why the plumber didn't just follow the hot/cold mains water pipework round as the problem rad is only 2m away at same level on opposite wall or simply run them in floor, probably took more effort and tons more pipe to do it how it has been done.

 

With severe tweaking of other rads and boiler pressure at 2 I can get hot water to the inlet of the rad but never round and back from the return unless I kill other rads which don't want to do as a freezing house as it is.

 

Given the towel rad run from the bottom of those T's is so close could the return be going up the pipe and stopping the flow/return of the other rad ?

 

Any ideas on what I can do ?  The bathroom floor in picture is now tiled and finished.  I have worked out I can get from the problem radiator to the boiler by opening up a non tiled wall and bringing down a newly finished kitchen ceiling and lots of drilling through to garage but a lot of upheaval and mess and cost.  I could then tap that rad into the main flow and return right next to boiler somehow going into the 28mm pipe - just worried that might steal all the flow from the furthest rads in the system which are in the coldest rooms.

 

I can by removing a wardrobe and a portion of plaster (pretty easy) get to those T-junctions - is an option to plumb those 3 rads in series so they act as one long pipe effectively or am I on a loser with the big up and over flow in the vaulted ceiling ?

 

Guess no way of upping the pump in the boiler doesn't seem to be any speed settings in documentation, there was lots of discussion on size of boiler and those are coming back to haunt me now - wish I had sized pump and everything separately as we are freezing !

 

Any advice greatly appreciated.

 

Many thanks

 

Lawrence