microbore to 15mm flow problem.

[dougiexx]

Have a flow problem with my heating system. I have had this problem since I moved into the house. The original part of the installation is gravity fed and the drops to the rads is in 8mm microbore. The pump is on the upstairs landing, and there are 2 manifolds feeding 5 rads each close by. My problem is, the previous owners built a ground floor extension with 2 rads that never get even luke warm. This is fed in 15mm plastic, from close to 2nd manifold, and thro on-suite and down to annexe. I have fitted more powerful pump but this does not seem to help.
Have tried shutting down all rads in original installation and the flow just about reaches annexe (slightly warm only). Can get rads warm only by draining thro drain valve. Is it possible that the 2nd manifold in system is partially blocked where it joins plastic 15mm, or could the plastic pipe to annexe be pinched (don't know if heating ever worked there). Also, all my downstairs rads are fed from upstairs landing, and none have drain cocks. Is this normal? Thanks in advance for any help.

 

[JPC]

i think you about right.

the manifold can become blocked snd not allow flow down a pipe and or you could have pinched microbore. id go with draining down and having a look at the manifold...if its compression mayby take it out and clean it ?

I went to a house with this problem once and said solution worked.

 

[kevplumb]

..if its compression mayby take it out and clean it ?

last one i did the spark moved a pipe and the lot disintegrated

go steady

 

[dougiexx]

Thanks JPC, you may be right regarding the manifold. The pipe that feeds the annexe is in 15mm plastic. I am thinking that they may have pinched this when installing. Problem is I do not know if annexe rads ever worked. Was told when I bought house that they only needed bleeding. All the rads fed with microbore are working (although some take longer to heat up than others). The 2nd manifold which then joins the plastic down to annexe could be culprit. Only problem is, we had a new bedroom carpet fitted last week and guess where the manifold is. I'm going to be popular!