Heating has stopped working. BG engineer visits and diagnoses the problem as being a blockage in the radiator network somewhere. We have an old property with an old one-pipe system, so although BG cover the boiler, they don't cover the rads.
What confuses me is this:- when I run the kitchen hot tap, I get some hot water out (a bit tepid), and then after a short while the boiler is reporting F23; here's the sequence on the boiler from when the tap is first turned on:-
I know that the boiler has a valve that diverts the hot water from the primary heat exchanger through to the secondary heat exchanger to heat the water that comes out the taps. So I would think that the rads could be in any state - this valve has closed them off so what does it matter.
So why is this caused by a blockage in the rads? The central heating is not on - there is only DHW demand. Cold boiler pressure is 1.2 bar
What confuses me is this:- when I run the kitchen hot tap, I get some hot water out (a bit tepid), and then after a short while the boiler is reporting F23; here's the sequence on the boiler from when the tap is first turned on:-
- S10 - Hot water demand (hot water operation)
S13 - Ignition sequence (hot water operation)
S14 - Burner ignited (hot water operation)
~~ the above then repeats a few times over several minutes ~~
S53 - Delay mode due to lack of water in system (~2,5 mins.)
~~ then back to S10,13,14 again for a few minutes ~~
F23 - Dry fire protection (difference between flow and return NTC's too large) - No water in appliance, pump cable defective, pump blocked or defective, pump output too low
I know that the boiler has a valve that diverts the hot water from the primary heat exchanger through to the secondary heat exchanger to heat the water that comes out the taps. So I would think that the rads could be in any state - this valve has closed them off so what does it matter.
So why is this caused by a blockage in the rads? The central heating is not on - there is only DHW demand. Cold boiler pressure is 1.2 bar
