Boiler and tankless waterheater condensation problems and efficiency ratings. Explain?
There should be little concern for condensation damage to modern boilers when the unit is properly sized (sufficient BTU output for the home) and installed in accordance with the manufacturers recommendations. The fact is for every therm (100,000 BTU) of gas burned, 1.15 gallons of water (condensate) is produced by any gas appliance because of the combustion process. The major concern should be how the appliance removes the condensate. Boilers are designed to either evaporate the condensate, drain it to an external source, or do both. A tankless water heater is not a boiler. It simply evaporates any condensate by having a very high BTU burn-rate at a low flow rate. Under the right conditions however, it will condensate like any low-mass boiler. So both units produce condensate because of combustion. The other concern is heat exchanger failure caused when condensate is abundantly produced because of system design parameters. When cold return water as is prevalent in a radiant panel syst
