Toyotomi Oil Miser OM-122DW Semi On Demand Water Heater

Save energy and save money with our efficient reliable on-demand water heaters. On-demand water heaters only heat water when you need it and never run out of hot water. Ultra efficient, compact and quiet the Toyotomi On-demand water heaters are rated can heat up to 240 gallons per hour!


  • Economical: Some consumers have reduced hot water heating costs by up to 70%!
  • Heats the water you need, when you need it…up to 240 gallons per hour!
  • Consistent water temperature.
  • Stainless steel heat exchanger!
  • 88% efficient!
  • Proven trouble-free performance
  • Safe: UL, CUL, home and mobile home approved!
  • Direct vent (as shown below) or chimney vent!
  • Small, compact size
  • Limited 10 Year Warranty


Type Combustion Type – Pressure Vapor
Flue Pipe – Forced Flue
Heating – Instantaneous
Source of Water – Direct Connection to Main Supply
Ignition High Voltage Discharge Spark
Fuel Type ASTM D3699 K1 Kerosene
ASTM D396 No.1 Fuel Oil
ASTM D975 Ultra Low Sulphur Diesel (ULSD)
ASTM D396 No.2 Fuel Oil (home heating oil)
Efficiency 88%1
Hot Water Output 148,000 BTU/hr
Fuel Consumption 1.1 gal./hr
Max. Hot Water Temperature 155°F (approximately)
Water Flow Rate/
Temperature Rise
6.1 gal./min. (40°F rise)
4.8 gal./min. (50°F rise)
4.0 gal./min. (60°F rise)
3.5 gal./min. (70°F rise)
3.0 gal./min. (80°F rise)
Capacity of Heat Exchanger 5.10 gallon
Area of Heat Transmission 9.7 ft.2
Fuel System Tank2
Dimensions (WxHxD) 12-5/8" x 27-3/4" x 22-1/2"
Weight 86 lbs. empty
Vent Pipe Hole 4-3/4" diameter
Max. Length of Flue Vent Pipe System
10 ft., 3 bends or less
Electric Rating 120 Volts AC, 60 Hz
Ignition - 110W
Burning - 98W
Required Accessories Fuel Strainer, Temp. & Pressure Relief Valve and Flue Pipe Installation Kit or 4 or 5-inch Chimney Adapter Kit
Exhaust Air Temperature Less than 500°F
Nozzle Quantity of Vapor - 1.1 GPH
Spraying Angle - 60°
Temperature Fuse 282°F
Electric Current Fuse 5A

(1) Heat and vaporized water are produced by the combustion process of this water heater. This rating does not take into account heat loss due to condensation of water vapor.
(2) Existing tank or purchase tank from local supplier.

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