I agree with bazdaman.
I'd advise you to get a second opinion. Why has he had to increase the pilot? If he had any doubts about the gas valve, he should have raised these before he left the job, not second guessing afterwards when he thought everthing was ok.
James.
He serviced a BBU & left it in working order. No one can tell to what extent the explosive ignition was, we were not there.
True we were not there, so his 'service' may not be what I call a service. One thing he hasn't done is repaired a fault (something I class as different to a service). Someone on here must think that explosive ignition is a sign of the appliance functioning safely.
James.
Granted Jaz & it's a good point. But we're only hearing the OPs take on events. So perhaps it's not so wise to jump to any conclusions based on that.
Remember, there's only cowboys Builders/Plumbers in the public's eyes. Open forums can only feed the fire of that misconception!!