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Glow worm flexicom 24hx - Error F25 problem

Discussion in 'Plumbing and Central Heating' started by AL, 2 Feb 2021.

  1. AL

    AL

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    Hi Guys,

    Hoping someone out there can help a DIYer with some ideas as I'd like to rule out any simple things first before calling in an expert.

    So I have a Glow worm flexicom 24hx with an intermittent Error F25 error. I read that this indicates low pressure / poor circulation. It is on an old f&e system, I've taken the pump off and visually inspected it (had some build up but not enough to cause issues). I suspected the pump as the downstairs rads don't get very hot unless I switch off the upstairs rads (they have TRV's) - the system might just need rebalancing though.

    I did try running some X400 through the system and that seemed to magically clear the fault and all the rads got nice and hot (inc downstairs ones) until about 4 weeks later and the error re-occured this reminded me to drain down the system to remove the x400 and i refilled & topped up with inhibitor.

    Low and behold the problem's back :( I have assumed the issue is to do with sludge/build up in the crappy micro bore system I have, I'm about to try again with cleaning chemicals but wonder if i'm missing something obvious that i've overlooked. Maybe i didn't clean out all the muck as I only drained down from one point?

    When I drained down the system it didn't seem dirty at all :-/

    Thanks in advance

    Al
     
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  3. Agile

    Agile

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    It is always possible that the pump is faulty and does not have enough torque.

    I would test it manually by seeing how much effort it needs to stop it turning. But that can be messy and not easy for a DIYer.

    Sometimes it is possible to check the torque with a screwdriver at the pump bleed screw. But some pumps do not have a well defined slot and that can make that more difficult.

    It is so much easier when you go to boilers regularly and have knowledge of how parts "feel".

    Sometimes a pump capacitor loses capacitance and reduce the torque. Easy to measure if you have a meter which will read around 2.6uF capacity.
     
  4. AL

    AL

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    So it could still be the pump? As you rightly say i have no reference to know if the torque feels ok or not. It is 8 years old so might have reached end of life?

    I suppose I can take a punt and replace the pump (Grundfos 15-50(130) @ ~£200) or get in a pro and if they diagnose the pump and replace it'll be £400+. Conversely if it's something else it'd be money saved.

    Times like this I wish I had a crystal ball :)

    Al
     
  5. AL

    AL

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    Little update, because I'm a curious soul (and an engineer) I tested the torque of the motor and it seems pretty weak - obviously i have nothing to compare with but...

    From stand still (motor off) i can easily hold the motor by gripping the shaft of the screw driver between my finger and thumb

    With the pump running, light to moderate pressure with a screwdriver easily stops the motor from spinning.

    All this said, unimpeaded the motor gets up to speed quickly and is definately spinning so surely the water is moving round the system?

    Anyway, I have put more chemicals in the system and will give it another clean out. In fact I just saw a cheap replacement pump here https://www.screwfix.com/p/grundfos-ups3-15-50-65-domestic-heating-circulator-230v/503fh which i think should replace the one I have? And it's probably the same price as a plumber's call out charge so think i'll switch out the pump at the weekend and see what happens - worst case i'll have a spare pump I suppose.
     
    Last edited: 2 Feb 2021
  6. Agile

    Agile

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    For an engineer you need to be more specific about how easily you can stop it turning with a screwdriver!

    I use a two finger definition!

    A man's two fingers should quite easily stop it turning.

    A woman's two fingers should be able to stop it turning but not quite so easily!

    But again the screwdriver handle, ridged or smooth? They all have an effect.

    But there are other possible causes and checking motor valves should be done before replacing any parts.

    Most boiler pumps do not have any speed control but if it does then it needs to be on setting III
     
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  8. AL

    AL

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    Sorry, i had just edited my previous response 'holding the shaft of the screw driver between finger and thumb' - I'm an average sized 6ft bloke.

    I'm not a proper engineer (Software Engineer- but still inquisative as to how things work) :)

    Yes the speed setting is on #3

    And thanks for your responses by the way ;)
     
  9. Agile

    Agile

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    And the diameter of the handle also has an effect too.

    Software? That's odd to me!

    This 10 y.o. laptop on W10 takes 10 -20 minutes to get to the log in screen and there is nothing that I can measure, poke, look at or feel to find out what it is doing ! I use AVG and Malwarebytes to clean it and they find nothing wrong!
     
  10. AL

    AL

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    lol - yes a 10 year old laptop practically a classic :)

    With laptops, phones tablets etc there always built in obsolescence. Problem is the software gets updated and is designed for the latest and greatest, so when you run the new software on an old system it struggles. You can spend money increasing the RAM and switching to a solid state drive but often in this throw away age it's cheaper to buy a new machine with the latest specs and then repeat every 3-5 years :-/

    You might find this answers your questions (a bit) https://www.laptopmag.com/articles/find-windows-10-program-load-time
     
  11. AL

    AL

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    Just an update (in case it helps others): I changed my central heating pump for a cheap https://www.screwfix.com/p/grundfos-ups3-15-50-65-domestic-heating-circulator-230v/503fh it was a pretty easy DIY job, would have been easier if the gate valves shut off properly (had to drain down the system a bit) - took probably 45 minutes. I can report the problem has been fixed, all the rads are nice and hot again and no more boiler codes and most importantly the Mrs is happy ;)

    Al
     
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