PURPOSE: To make easy the proper use of an outdoor air supply and discharge type or an indoor air supply and discharge type and to keep a fuel-air ratio at the time of combustion almost constant in either case by opening the exhaust pipe connecting part of the combustion part in the vicinity of a blower for convection.
CONSTITUTION: In the case of using the hot air space heater as an outdoor air supply and discharge type, combustion air is supplied from the outdoors through an air supply and discharge cylinder 20, and an air supply pipe 22 by an air flow generating part 13a. A combustion waste gas generated in a combustion chamber 15 returns again to an air supply and discharge cylinder 20 via a heat exchange part 16, and an air discharge pipe 19 and is discharged to the outdoors. Indoor air of a low temperature supplied from a convection blower 17 is heat-exchanged at a heat-exchange part 16, and is discharged through a hot air outlet 12a in the form of a high-temperature air flow. On the other hand, in the case of the hot air flow space heater as an indoor air supply and discharge type an air discharge duct 23 is mounted on a discharge air pipe connecting port 18 after removing an air discharge pipe 19 and an air supply pipe 22, and a pressure loss regulating damper 24 is loaded at an air flow generating part 13a. The proper use of the title space heater as the outdoor air supply and discharge type and an indoor air supply and discharge type is very easy and in either case, the function of a burner does not almost change.