Posting a message to the forum will remove the above advertisement
  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.
  2. Checkout our Plumbers Insurance area - heavily discounted Public Liability Insurance and Van Insurance specifically designed for plumbers.

Discuss Bizarre central heating problem?? Please help before I go insane!!!! in the New Member Introductions area at

  1. TheGMan1972

    TheGMan1972 New Member

    Hi Guys,

    Thanks for reading this.

    I have a Worcester 25si boiler with [originally] 7 rads. We had a conservatory fitted and had another rad installed in there. Since then the heating downstairs has slowly gone kaput!

    I'll try to describe the system we have to you. We have the boiler in the kitchen downstairs with a T junction on the feed and return pipes coming out of the boiler. These have pipes going up and down. On the pipes going upwards we have four rads upstairs & 2 rads downstairs (three bedrooms, hall, lounge and bathroom which is always on). On the pipes going downwards from the boiler we have two rads (kitchen and conservatory). These are the rads we are mainly having issues with though am having problems with them all TBH bar the one in the bathroon (which is the one that's always on) Most rads feel hotter round edge/top than in the middle/bottom.

    The conservatory rad was added last to the initial system of 7 rads (making 8) via another set of T joints about 1 metre from the feed and return pipes coming from the boiler.

    Initially everything got nice and hot (and toastie!) We were happy :)

    The kitchen rad & conservatory rad slowly failed until both were stone cold :(

    We had a problem with the pressure gauge showing 2 bar despite being full/empty so I swapped this (fixed now) The pump IS working and the rotor is free of debris. Whether it's running at the correct speed is another matter (heard capacitors on pumps can go skew-if! It's a Bosch Grundfos 15-60 pump). It's running though - I can feel it by opening the bleed valve and putting a screw driver on shaft - still turns if I add a good amount of pressure - I can also hear it running. Blades in rotor are also free.

    Radiator in kitchen gets hot round sides and top edge. Have had rad off and thoroughly cleaned it/banged it with rubber mallet - there's nothing in it now - no magnatite or anything - got that out previously. Re-added it to system - filled it and bled it - same - hot round edges & top - cold at bottom. Doesn't make sense - can turn off conservatory rad and leave kitchen rad open - same result so can't be sludge etc in conservatory rad causing issue though I will remove this weekend & clean.

    Have added Fernox F3 (Sunday) - don't think it'll work (or power flushing) as I don't think said rads are actually blocked - am wondering if pump is running slower than it should be. Does this happen?? It's the original pump fitted in boiler and has been in system from 2004. Pump is nice and free and feels like it's giving oomph to system.

    Just want hot rads all over (or more uniform) - don't care if I have to remove each one in turn and remove sludge but I'd have expected Kitchen one to be better if cleaned twice - feels like NO obstruction but as I say, warm round edges and top - elsewhere cool.

    Any clues here? As I say.. hoping to look at it again this Sunday but want to fix it once and for all - fed up of doing stuff and it doesn't rectify issue.


  2. TheGMan1972

    TheGMan1972 New Member

    BTW, have balanced system - not that I know what I'm doing !!! Have closed all rads upstairs and opened 1/4 turn to try and push more heat downstairs. Downstairs rads are 3/4 turn open. Any clues???
  3. Riley

    Riley S. Mod Trusted Plumber GSR Top Contributor!!

    For a start you shouldn’t be inside your boiler as you need to be gas safe to remove the cover.

    It could be sludge drain a little water off from the rads and see how grubby it is.

    Have the tees off another rads feeds to the radiator in the conservatory.
Similar Threads - Bizarre central heating Forum Date
which fitting? radiator 15mm pipe to central heating valve Plumbing Forum Saturday at 9:15 PM
Central Heating pipes for Cold feed Plumbing Forum Saturday at 7:46 AM