Open vented system, No HW or CH, BAXI 80HE boiler shows Ignition Lockout after tried to start a few times

[fandyman]

Ok checked the flow and return at the boiler and they 62C and 53C correspondingly.

 

[Johntheo5]

Was that with HW&CH or just HW?

You said you would do the HW only test today with pump to CP2, if you do just monitor the boiler flow&return temps + pump power.

If the cylinder stat is set to 60C then the boiler will never cut out with a flow temperature of 62C, requires ~ 70C.

 

[fandyman]

That was HW&CH for now.

 

[Johntheo5]

So, with HW&CH on boiler output is, 13.3*60*9/860, 8.35kw, hardly enough to keep the boiler from cycling.

 

[fandyman]

I checked the HW only now and the pump shows 34W on CP2 while the temp readings on the boiler flow is 60C and return 50C.

 

[Johntheo5]

Same flowrate as with HW+CH, 0.8m3/hr, 13.33LPM, dT, 10C, blr output, 13.33*60*10/860, 9.3kw, just enough to keep the boiler constantly firing, will probably change depending on the cylinder temperature.

I don't think you can do much more now, bearing in mind the thread title was about ignition lockout which has gone away.

 

[fandyman]

What would be the long term solution? To have HW firing on demand?

I have this problem every spring to summer.

 

[Johntheo5]

Yes, your best bet is to fire the HW only, say a hour or so in the morning before the CH and something the same in the afternoon/evening.
In the summer, you require HW only so you could change to CC3 @ 6.4M but as the pump will be running at full power, 45W, you should get ~ 0.88/0.9m3/hr, say 14.6LPM, at 5.4M, which will squeeze a bit more out of the coil and keep the boiler running continuously for longer.
Of course increasing the boiler flow temp to max will give another boost and not cost a fortune in the summer with HW demand only.