No water to Boiler

[Set One]

I have a BAXI Solo boiler. Today it failed to start up. No Fault indication initially but after bleeding the pump (to no avail ~ no water bleeding out) the fault indicator shows "no water flow or reverse flow". It appears there is no water feed to the boiler. The header tank is full with no restriction at the outlet. Opening the drain at the boiler inlet produced about 2 litres of inhibited water ~ I suspect this came from the outlet side of the boiler. I am now about to lift the flooring in the loft (bungalow) to investigate further. The pump is reasonably new and runs okay. (not seized).
Any ideas and suggestions will be gratefully received. Thanks

[Set One]

Problem sorted.
There was in fact a blockage from the header tank that tops up the system. It appeared to be at a T joint where the header tank feed joined the inlet to the pump. It seems to me that as the system is not topped up frequently by the header tank, silt had built up, together with calcification ( we are subject to very hard water). I had to break the T joint (soldered) and disconnect the pipe from the header tank and literally "blew" the obstruction out. Hence the vagueness as to the cause of the blockage.
Difficult to pinpoint but satisfying to rectify.

[plumbbob]

Blocked feeds particularly in gravity systems is far more common than you might think. Glad you have solved the problem.