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Discuss Worcester Greenstar 24ri - Possible airlock? in the Gas Safe Register Forum - Public Forum area at UKPlumbersForums.co.uk.

  1. JE-P&H

    JE-P&H GSR

    Replaced an old Ideal Concorde WRS225a with a 24ri today, on fire up it lights for couple of seconds and overheats causing banging pipes etc.

    Couldn't find a manual for the Ideal so assumed flow was on the left and return on right as left came out from top of heat ex and right from the bottom. (Check with Ideal who confirmed I was correct but still considering it's a possibility)

    Have a drain off on the return so tried mains water into the system with no luck.

    Boiler is in the garage with about a 8m run to the airing cupboard where the pump is, flow pipe barely gets hot past top of the boiler. Any suggestions would be great I'm struggling!
     
  2. PhoenixServices

    PhoenixServices Plumber GSR

    Have you bled the heat exchanger?
     
  3. JE-P&H

    JE-P&H GSR

    Ye bled from the vent on the top, no air just hot water!
     
  4. Destroyer2813

    Destroyer2813 Plumber GSR

    Checked the simple things right pumps running valves are open filter vales or anything ?
     
  5. JE-P&H

    JE-P&H GSR

    Ye pump runs ( Can hear it and changes through speed settings) zones valves both opening and are new, pump is still original was working fine before I assume as they had HW do newer boilers need a strong pump could be weak but unlikely?
     
  6. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    how fast does it temp up?
     
  7. JE-P&H

    JE-P&H GSR

    About 10seconds, fires up full then goes low, then out as it overheats. Flow pipe goes red hot above boiler and return gets hot but it doesn't loop, the pipes just get hot off the boiler if that makes sense!
     
  8. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    would say air lock

    shove your hose on the drain off and drain it off for a good 10 mins on the return then do the same with the flow
     
  9. JE-P&H

    JE-P&H GSR

    Ye same I was thinking tomorrow drain it down put lever valve on flow and one on return. Then mains water through the drain off isolating one side at a time to try and push it through but if that doesn't work I'm stuck haha!
     
  10. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    dont you have a mag filter fitted?
     
  11. JE-P&H

    JE-P&H GSR

    I Quote them as optional customer opted out, not my choice but what can you do!
     
  12. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    just thinking saves you draining down if you did

    would put some lockshield gate valves instead of lever valves
     
  13. JE-P&H

    JE-P&H GSR

    Ye it's typical majority of installs have a filter but not this one! Didn't think of lockshield gate valves good alternative thanks!
     
  14. JE-P&H

    JE-P&H GSR

    Still no luck, drained everything including the boiler installed 2 AAV above the boiler shut off a valve each side and tried to pull an air lock through any other suggestions?
     
  15. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Are you getting just water out ? Or nothing

    If your getting water could be pump
     
  16. JE-P&H

    JE-P&H GSR

    Just water, I have now changed the pump still the same have also swapped Flow and Return round above the boiler temporarily to see if that does anything and no luck! Baffling me system was quite old fully pumped system before but had no motorised valves etc just a Damfoss mixing valve controlling the hot water temperature anything I could have missed?
     
  17. JE-P&H

    JE-P&H GSR

    Photo of pipework before I took cylinder out if that helps!

    I have labelled them left to right as they come out of the floor Boiler flow, Boiler Return, CH Return and CH Flow anyone disagree?

    IMG_3421.JPG
     
  18. Gasmk1

    Gasmk1 GSR

    is pump on flow or return might make a difference
     
  19. JE-P&H

    JE-P&H GSR

    I would say Flow? From the picture above it pumps to the cylinder and is on the flow pipe into cylinder?
     
  20. Chuck

    Chuck Active Member

    Deleted after I re-read the OP.
     
  21. JE-P&H

    JE-P&H GSR

    Here's a picture just after I changed the pump with my pipework anyone see anything I'm out of ideas now haha!

    IMG_3443.JPG
     
  22. Gasmk1

    Gasmk1 GSR

    I think you should have put an air vent on the top of the heating coil, could be locking up there
     
  23. JE-P&H

    JE-P&H GSR

    Where do you mean top of the coil? I don't think it's an air lock anymore I've put mains water through the system right up to the tank and still boiler flow doesn't even get hot heat exchanger just overheats.
     
  24. Matchless.plumb

    Matchless.plumb Trusted Plumber

    As @ShaunCorbs@ShaunCorbs mentiond earlier it might be your pump itself. @Gasmk1@Gasmk1 said you should put an AAV on top of the coil which means where the inlet to the coil is - basically close to the coil entrance. If there is no airlock anymore try getting another pump that's what I would to see if there is any difference.
     
    • Disagree Disagree x 1
  25. Chuck

    Chuck Active Member

    This is turning into quite a mystery.

    Neither of the following are likely, just trying to think outside the box:

    Can you be sure that the coil in the cylinder is not blocked? Perhaps a manufacturing problem. Perhaps some bungs to stop debris getting in that needed to be removed...

    I can't see from the photos, does the cylinder have a secondary return? Is it possible you connected to this and capped the primary return instead of vice versa.
     
    • Like Like x 1
  26. Matchless.plumb

    Matchless.plumb Trusted Plumber

    Perhaps you mixed some pipes
     
  27. JE-P&H

    JE-P&H GSR

    If the coil was a blocked surely CH and bypass would still work so boiler would still fire?

    No secondary return on the cylinder just your standard fittings, I didn't cap any pipes tee all the returns in together and used the CH Flow. Open to suggestions if I've mixed something up? I checked the installation instructions for the old damfoss mixer and return comes out the bottom as I expected.

    It also now has a new pump on no change!

    Got Worcester coming tomorrow to check the boiler to rule that out, took the flow and return off and blew through to ensure no blockage etc. All clear!
     
  28. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Have you opened port valves manually ?

    Do you get any heat up to where the pump is ?
     
  29. JE-P&H

    JE-P&H GSR

    Ye opened them manually, no heat and the pump heat doesn't get past the top of the boiler it basically boils itself in about 10-20secs then flow sensor cuts in! Takes a while to cool then same again!
     
  30. Matchless.plumb

    Matchless.plumb Trusted Plumber

    There is only one thing left the boiler itself. It would be quite weird if the boiler is ok.
     
  31. JE-P&H

    JE-P&H GSR

    I know I've ruled everything else out as far as I can see but Worcester technical just say it's a circulation issue so I have asked for an engineer visit as the Heat literally doesn't leave the boiler!
     
  32. Matchless.plumb

    Matchless.plumb Trusted Plumber

    I know you've changed the port valves but perhaps faulty ? It would be very weird if two are faulty but just trying to figure the solution
     
  33. Chuck

    Chuck Active Member

    Tell us something about the controls. Is it possible that the circulation is not starting until a few seconds after the boiler fires?
     
  34. JE-P&H

    JE-P&H GSR

    Pump is wired to the boiler on these, so the boiler controls it and sequence seems fine valve opens pump runs boiler fires then over heats! All Honeywell controls, room stat, cylinder stat, timer, valves etc.
     
  35. Chuck

    Chuck Active Member

    All good then.

    Is the CH feed tank working correctly, i.e. not emptying when the pump starts and hence letting air in to form an airlock? Any 'inverted-U' sections of pipework that don't have bleed valves on them?

    What model of pump and what is the height difference between the pump and the water level in the CH feed tank?
     
    Last edited: Jun 18, 2017
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