(2) Heater where fire is extinguished  within three minutes after ignition  when there is no water in the heat  exchanger  (3) Any other heater  Directly-heated heat  exchanger for a bathtub  water heater  (1) Heater with such heat exchanger  (2) Heater without such heat exchanger  Oil tank  (1) Heater of which oil tank is combined  with the heater body  (2) Any other heater  8. Oil- fired  Bathtub  Water  Heaters  Combustion type  (1) Pot-type heater  (2) Pressure-spray-type heater  (3) Any other heater  Air supply/exhaust type  (1) Heater with forced aeration  (2) Heater with forced exhaust  (3) Open-type heater  (4) Any other heater  Circulation type  (1) Natural circulation heater  (2) Forced circulation heater  9. Oil  Stoves  Air supply/exhaust type  (1) Closed-combustion stove  (2) Semi-closed-combustion stove  (3) Open-combustion stove with forced  aeration  (4) Open-combustion stove with natural  aeration  Type by use  (1) Stove with forced convection  (2) Stove with natural convection  (3) Any other stove  Heating oil  consumption amount  (limited to an open- combustion stove with  forced aeration)  (1) Stove with heating oil consumption  exceeding 7 kilowatts  (2) Stove with heating oil consumption  of 7 kilowatts or less  Design of a space  between the bottom  surface of the stove and  the stand or the floor  (limited to a closed- combustion stove or a  semi-closed-combustion  stove)  (1) Stove designed with such space  (2) Stove designed without such space  Oil tank  (1) Stove of which oil tank is combined  with the stove body and which has an  airtight oil tank  (2) Stove of which oil tank is combined  with the stove body and which has no  airtight oil tank  (3) Any other stove  50 