baxi bahama problems

[davyboy10]

Hi,
I have just attended a property that has a Baxi Bahama combi. The boiler fires up on hot water or heating but then shuts down after about 12 seconds and doesn't fire up again until after 3-4 minutes. The pump is working fine and there is no kettling with the boiler when it fires up. The divertor valve goes back to the central heating mode once the tap is shut off.

Does this indicate that the bolier is either blocked, bearing in mind that the same fault occurrs on heating or DHW or should I be looking at changing the pump, any ideas to what else could be causing this, thanks.

 

[baxpoti]

What are your high and low gas pressures?

Does it modulate?

Has the front panel swithing got red (or black) around the outside?

 

[davyboy10]

The low gas pressure is on about 2 m/bar and the high is around 10 m/bar
The 2/ m/bar is on the heating and the DHW goes towards 10. It doesn't get chance to modulate because it shuts down in about 10 to 12 seconds

 

[Baxmax]

Split A.P.S tube ?