Code F5

Discussion in 'Plumbers' Talk' started by gswainyboy, Jun 9, 2019.

  1. gswainyboy

    gswainyboy Member

    Hi Teach.Firstly there is no fault code so I dont starts up again on its own The temperature varies but has got to 76 at times.There was no air from any rad when i bled them and all were up to temperature this morning.This is happened and i took note so that you have an idea of what is going on
    Turned stat up so I knew this wouldnt cut in and out
    C/H timer switched to constant
    Boiler started up to 70 then off
    7 mins later it restarted (on its own)
    up to 63 then off
    2 mins back on
    straight off
    straight on
    on up to 76
    2 mins then on up to 77 then off

    etc etc
    The Teach likes this.
  2. gswainyboy

    gswainyboy Member

    Morning all.No code displayed and dont have to reset it Teach and temperature varies but is usually 68-70ish .it restarts on its own.I dont seem to be able to get final bit of air out of the system though.I have bled and bled and bled all the rads,which are all working exactly as they should but every now and again the boiler bangs,Is this kettling,and it is air that is doing it but I just cannot get rid of it,thanks for any ideas,Graham
  3. The Teach

    The Teach Screwfix Select

    seems the boiler is getting hot rapidly and cycling more than it should,The system could be creating excessive air bubbles and dumping the air into the radiators.

    Is the pump the original,it could be slowing down ;)

    The system could be pulling air in from a few sources :( Or the system is still settling down from the recent drain down.

    Does the system have an auto air vent fitted or a manual air release valve ? usually fitted adjacent to the pump-motorised valves & cylinder.

    the boiler thermostat is likely to be set already at number 2 setting,if any higher its worth trying the boiler at 2.

    there may be some scale in the heat exchanger,

    As it was fitted by BG they would know how to set up the kw output on this hybrid glowworm boiler to match the system requirements,The boiler is usually supplied at mid range 18kw output,sometimes supplied at 31kw depending on the production date.
    Maybe during the next boiler service ask the technician to confirm the boiler output is correct for the installation size and ask if the boiler modulates to the correct gas setting.
  4. Mike83

    Mike83 Screwfix Select

    Could still be debris moving around the system.
    Also could be deposits on the pump impeller.
    Hopefully it settles down the next couple of days.
  5. gswainyboy

    gswainyboy Member

    Yes,same here Mike.It seems that the whole problem has been solved thanks to your advice on here but it is just what I am sure is the final bit of air occasionally making the boiler noisy (Kettling I think) But we ahev all rads working ok and full hot water now thanks

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