Boiler Overheating: Valliant Boiler Error F20 and F83

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Hi There

I have the wireless starter kit V3 with Tado TRVs on 14 radiators. 6 of them are independent (ie in a room with one radiator) and the remainder are in rooms with multiple radiators. (2 x rooms with 2 rads, 1 x room with 4 rads). When I look at "Rooms and Devices" in the app it seems like they are correctly configured.

I have 4 radiators with standard valves (three towel rails and one small radiator towel rail combo) which I treat as the always on radiators.

The boiler resets each night and shows an error F20 or F83 (NTC temp gradient). I've googled and the explanation given is: boiler is detecting a temperature change in the flow and return pipes that is not as it should be

I have to reset it each day, sometimes I have to reset it a few times before it works. It will then work throughout the day but the fault occurs overnight.

Would anyone have ideas on how to fix this?

Comments

  • johnnyp78
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    I might be wrong on this, but it sounds more like a problem with the boiler or your pipes than with Tado. I’d get a professional in to check it.
  • TerryUK
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    I would love to know if you manage to find out what this is, a family member of mine has a very similar setup with the Tado and TRV's on all rads, probably just a coincidence but they get the F83 error message randomly, sometimes every day, sometimes it will be fine for weeks. Seems to be more frequent when it's colder outside. We have been back and forth with Valiant for over 2 years and they insist nothing is wrong with the boiler. The rest of the central heating and hot water system has also been replaced along with some pipework as well as a power flush and the error persists! We have had about 8 heating engineers out over the past 2 years and nobody can work out what's causing the error!

  • Montage
    Montage ✭✭✭
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    I think the F20 and F83 are opposite ends of the temp spectrum, but they are either real fault conditions or faulty sensors.

    I'd expect the starting point would be the NTC thermistors and making sure they are fine. If they are correctly reporting, there's a real fault to fix in the system.

  • GrilledCheese2
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    Stop resetting your boiler. F20 is an overheat fault. Persistently overheating the boiler is going to weaken the heat exchanger and may cause permanent damage. A new heat exchanger is an expensive repair.

  • Mikeymoo
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    There are two things that might be connected to this:

    1) we had the heating system flushed recently. It was filled with sludge. This problem has been happening regularly since.

    2) there are 2 radiators fitted backwards which the plumber only noticed while flushing the system.

    Could these be causing the fault?

    Strangely, the fault only happens at night. The heating works all day but switches off at night when demand for heating is very low.
  • Mikeymoo
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    Little update for anyone who finds themselves on this thread. After many plumber visits the issue is resolved. The air release valves (I forget there proper name) on top of the boiler were stuck in a shut position and as a result air was trapped in the system. I frequently bled radiators but there was still a blockage in pipes that had to be forced out.

    We haven’t had the issue in quite a while.