(Special Order Item)
These are replacement oil metering valves for stoves and heaters.
These valves are available factory calibrated for 3 fuel oil viscosities.

Being the most common diesel fuel, oil metering valves installed in stoves and heaters are calibrated for #2 diesel, unless otherwise requested.
Burning #1 diesel (stove oil) will allow 25% more fuel, and burning kerosene will allow 50% more fuel, to flow through a "D" calibrated oil-metering valve.
Because of this, it is important to burn the fuel for which the heater has been calibrated.