My diesel heater direct experiences have been with the old Espar 3DL heater, which my boat was originally commissioned with, and the Espar Airtronic 4D upgrade I installed last year.
The system I have is actually simple, consisting of a diesel fired furnace unit ignited by an electrical glow-plug. Diesel is delivered to the unit via a low amperage, in-line metered pump
. Integrated circuitry regulates the required amount of fuel
to whatever temperature the bulkhead mounted digital thermostat calls for.
A stainless exhaust
conduit connects the combustion chamber to a stainless port, located on the exterior high side of the hull. Just below the aft cabin's rubrail on my boat - since it's 5'-10" above the water line
. Most other sailboats have the exhaust
located on the transom.
Fresh air is provided by an above deck intake vent. There are six individual, damper controlled forced air outlets, positioned throughout the boat, all connected to the furnace plenum by concealed, flexible round ducts.
The Espar 4D sips fuel
with the meter pump
and only uses .8 to 3.0 peak amps during use, 12 volts - so heating the boat away from shore power is of no big concern. More info on Espar is available HERE
if you're interested.