Radiators won't fill

Discussion in 'Plumbers' Talk' started by Big Vella, Aug 31, 2007.

  1. Big Vella

    Big Vella New Member

    I've just drained my central heating system, removed a radiator in the bathroom, fitted a new radiator. Gone to refill it and nothing's happening - water's not flowing

    Now discovered that water's not draining from the header tank.

    I think there's a blockage in the upstairs radiators.

    Is there a quick and easy way of clearing the system?
  2. paaulyb

    paaulyb New Member

    Blockage is probably in the feed from the header tank.

    Have you checked the outlet is not blocked in the tank?

    If clear the pipe is probably blocked
  3. --------- plumbing

    --------- plumbing New Member

    must times the blockage acures where the header tank pipe joins the main system pipework.
  4. Big Vella

    Big Vella New Member

    where abouts would the header tank pipe join the main system?
  5. Ion Transient

    Ion Transient New Member

    > Is there a quick and easy way of clearing the system?



    yeah..open the rad bleed valves
  6. Big Vella

    Big Vella New Member

    done that! the whole system's bleed valves were open!!!!!!
  7. --------- plumbing

    --------- plumbing New Member

    where abouts would the header tank pipe join the main system?

    poss in your airing cupboard near your


    yeah..open the rad bleed valves

    thats not going to clear a blockage is it.
  8. --------- plumbing

    --------- plumbing New Member

    sorry near your pump and cylinder
  9. Big Vella

    Big Vella New Member

    Many thanks for that ----------plumbing - going to give it a try tomorrow. Spent too long on it tonight

    I've read some of the other enquiries and also going to try flushing the system by connecting to the mains and draining the system.

    I'm assuming that reverse water pressure might clear the blockage between the header and main the system - as long as i watch it so that i don't flood the tank!!

    Watch this line tomorrow!
  10. ban-all-sheds

    ban-all-sheds New Member

  11. tightenit

    tightenit New Member

    Hose on the drain cock - other end to the mains - backfill. Job done.
  12. britishblue

    britishblue New Member

    Try manually opening any zone valves that are on the system.

    BB
  13. Big Vella

    Big Vella New Member

    I've managed to back fill all the radiators. Next problem is that they're not heating up - i think there's a blockage between the head tank and the main system.

    I've flushed the system in both directions but the head tank won't drain.

    HELP!?
  14. bathstyle

    bathstyle New Member

    You've clearly got a blocked cold feed pipe, if it's a proper blockage like most are then the only way it can be unblocked is by cutting into the pipe work and physically unblocking or by replacing blocked section of pipe work.

    If you follow the pipe that comes out of your header tank down into the airing cupboard it will eventually come to a tee, this is where it joins into the system and will need unblocking at this point.
  15. tightenit

    tightenit New Member

    Assume the boiler comes on and the pump is working, the stats are calling for heat, zone valves are open and all the rad valves are open? Does the boiler stay on or close down after a few minutes?
    The header tank feeds a 15mm pipe into a 22mm tee, usually compression and sometimes near the cylinder.If you drained the system and the header tank remained full the likely blockage is at this point.
  16. Big Vella

    Big Vella New Member

    Many thanks for everyone's wisdom. Got my local cplumber out to take a look. It appears the air/water filter / divider thingy is bloked up. The plumber used his magnet clearly showing the build up magnetic sludge.

    Cos the blocked part is pretty inaccessible i'm probably going to replace with a combi-boiler system and do away with all the tanks.

    Looking for estimates to replace with:-
    1) a valiant combi boiler
    2) 4 TRV
    3) programmable thermostat

    Can anyone guess-timate a price for this work?
  17. smithp60

    smithp60 New Member

    3 grand cash!!!
  18. tightenit

    tightenit New Member

    If you take your motor to 'Nick and Fit' and they tell you to replace front and rear discs as well as pads do you get your credit card out or go home and whip the wheels off and have a butchers? If you get your card out then go for a new system, if you have a look and get a few opinions then maybe a new boiler is needed. How about flushing the old one out?
    Yes we are in business to make money - but if you want a serious quote for a vaillant combi then tell us your heating and hot water requirements. I can knock a tenner of £3k for cash ;o)
  19. Captain Leaky

    Captain Leaky New Member

    The plumber used his magnet clearly showing the build up magnetic sludge."

    An old trick, don't fall for it, as tightenit says think about cleaning out your current system first.
  20. myzeneye

    myzeneye New Member

    back filling is one thing, but im not sure id ever knowingly leave a system running with a blocked feed & EXPANSION pipe..... only the open vent to block up before you blow a hole in the side of your house.

    like said 3k cash is bout right... i just did one for 2.6k cash but shouldve charged more really.... boiler in garage, removal of wall heaters etc....

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