| 摘要 |
An instantaneous type fuel-fired water heater has a variable speed blower that discharges combustion air into a fuel burner utilized to heat water flowing through a heat exchanger portion of the water heater. A portion of the air discharged from the blower bypasses the burner and associated heat exchanger, flows around the heat exchanger, and then mixes with flue gases being discharged from the heat exchanger portion into the flue portion of the water heater. In this manner, such flue gases are cooled by the bypassing blower discharge air to an extent permitting the flue portion to be formed from a low cost plastic material instead of a high temperature metal material such as stainless steel.
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