Condensing boiler not staying at max temp

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Basically, the boiler is happily running away but your not circulating enough water through it, so it watches the temperature of the water flowing in, how much it heats it and then what flows out, becuase your not getting enough flow through it, eventually it shuts down to its mimimum power (s.53) and does this for a while before attempting again, this is the period which your temp is dropping to the 40s and staying there for a while.

get the pump kicked on to three, then reset the boiler and try again, let us know if thats enough to get it running normal
 
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Do you have thermostat valves on the radiators? Is there one (or more) without one?
 
Theres a possibility of a restriction in your system in that case, will assume its not been fitted with a correctly set auto bypass valve either in that case.

Push "i" and "+" at the same time on boiler front panel

It should display d.0

press "i" to access the d.0 code, should probably then show "18"

using the "-" buttin change this to "12" and then press and hold "i" for about 4 or 5 seconds to set it

then press "i" and "+" at the same time to leave the menu, wait a minute and reset the boiler again.

This time it will start heating but a little slower to get up to 60 but should be able to hold there without issue,

12 is a randomly choosen power setting, that can be altered again up or down later
 
PS: Auto Bypass is required per the manufacturers of the boilers instructions, would typically be fitted pretty close to the pump and look like one of the following:

download (1).jpg
download (2).jpg
download.jpg
images.jpg
 
auto bypass picture 3 is installed, set to number 4
Ill try the d.0 now will report back tomorrow
 
Do you have a thermostat on the wall?
Open at least one TRV fully, the one where the room thermostat is if you have one.
 
reducing the setting seemed to work to an extent, as far as i can tell this seems to reduce the boost. Im setting it to 15 now and see how hard the missus is complaining of being cold when i get home tonight.

I have a fernox TF1 filter which i emptied about a week ago (no significant buildup), we got that because the heat exchanger kept getting blocked when the system was new.

Opening the TRV in the hall where the thernostat is doesnt work well, the thermostat is only a few feet from the rad and it just turns off the system continuously meaning other areas are cold.
 
That's what it's for. There shouldn't even be a thermostat on the radiator where the room thermostat is. If the system is going off turn the room thermostat up, not the radiator down.
 

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