ok Bill -- I bow to your testimonial of hand fired expertise
No questions there
but hand fired - automatic fired - or nuclear fired
if the guy was pumping too much (assumption) == and he has promised that he isolated the boiler from the load as a test of that - and if that (now questionable) over pumping was
defeating the transfer efficiency of the vessel and as you put it "The water is not in the boiler long enough to absorb the btu's being pulled out"--- THEN the boiler would be making set point and not operating below condensing temperatures. But that isn't what happen when you over pump a boiler - the boiler give up its energy to the water in the same way - but the energy is carried away too fast for the boiler to recover.
SO in an over-pumped gravity conversion - you get super long burn times - expensive system operation - and an uncomfortable dwelling. System balance remediation will fix this - YES a bypass or temperature reducing loop will also, but my point is - over pumping will not defeat boiler transfer efficiency - to the point that the boiler will not reach set point because the energy is not transferring from vessel to liquid. The exact opposite is the problem.
-- You must be confusing over-pumping load radiation. Then the load will never get hot because the energy fly's thru with out transferring to the load. HERE the boiler is not getting hot fired with coal
Hypothesis - the salesman suckered a customer
Conclusion - the appliance SUCKS as a coal fired unit. Hand feed or otherwise Ill bet