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Vaillant Boiler Issue

Discussion in 'Plumbing and Central Heating' started by AJNewie, 15 Mar 2021.

  1. AJNewie

    AJNewie

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    Hi guys,


    Hoping for a bit of advice as boiler has gone down with a 3 month baby in the house!


    Have a Vaillant Ecotec 418 has worked pretty solidly for 5 years.


    In Oct 2020 we had a sealed system fitted to improve water pressure and get rid of header tank in loft.


    Boiler copes absolutely fine when HW and CH are running at full.


    On 2 occasions, have been out for the weekend and turned HEATING down (only to 14, would assume still ticks over) and left HW on, yet come back to find error codes. Usually an F23 which tends to be sorted with clearing faults and eventually re-starts.


    However last night, tried to clear F23 fault and boiler reset and got upto higher temp than before. Came back with F83 fault, tried to clear that, the boiler reset and now are stuck with F72 fault.


    I know it sounds daft just clearing the faults and restarting boiler on these occasions, but had been told to give it a go and it had worked on the other occasions and boiler cntd to work fine for a month.


    Any guidance appreciated! A lot of blankets needed for the baby last night!!!
     
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  3. muggles

    muggles

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    As you've suggested, continually banging the reset without getting any fault diagnosis isn't going to help the situation. The faults you're getting could be due to low system pressure, the pump failing, or a combination of the two. They could also potentially be due to heat damage to the wiring inside the boiler if it's not been serviced properly for a while. Lastly it could be a faulty temperature sensor, but in 15 years I've never seen a Vaillant temp sensor fail of its own accord so I feel that's unlikely.
     
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  4. picasso

    picasso

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    F83/f72/f23 are all temperature related so check water pressure and then pump before anything boiler related.
     
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  5. Mottie

    Mottie

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    I have a Vaillant EcoTEC 418 that has been converted to a sealed system. It doesn’t have a pressure switch like you would see on a combi boiler to switch it off if the pressure is too low or high so how would the boiler know? I have often wondered if I could have one fitted to protect my boiler. Is this possible?
     
  6. picasso

    picasso

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    Easy enough, put one of these on the pipework and wire the main feed to boiler through the switch.

    Potterton 910026 Pressure Switch Kit Water (manomano.co.uk)
     
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  8. muggles

    muggles

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    I know it's not got an internal pressure switch. Generally it would only happen if the boiler was at the top of the system and thus being starved of water. You could certainly fit a remote pressure switch to break the switch live to the boiler. Just make sure you document it well so that you know what's happened when the boiler doesn't fire up!
     
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  9. ianmcd

    ianmcd

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    Your boiler measures the differential between the flow and return pipework, that is how it senses if there is a flow problem or low water pressure
     
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  10. Mottie

    Mottie

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    Ah, thanks. (y) No pressure switch needed then. I always wondered what would happen if the pressure ever got too low.
     
  11. ianmcd

    ianmcd

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    Yes the boiler measures the different temperatures between the flow and return, and if the differential is too high it will shut down, is it the best way ? not sure, low water content switches can block up, flow and return NTCs can go faulty, both systems have their faults to be honest
     
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  12. AJNewie

    AJNewie

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    I think that was what I couldn’t get my head around - was fact that couldn’t find out if the pressure was too high or low on the boiler. But pressure on the sealed system was what I needed to get to.

    Managed to fix now and was pressure. Thanks for all help. Really appreciate
     
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  13. DIYnot Local

    DIYnot Local

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