The Espar Hydronic 10 is a diesel-fired coolant heater that heats the crane's engine coolant and the oil
in the hydraulic tank. The heater consists of a water pump, a heat exchanger, and an electronic control
system. The unit pumps the engine coolant into the heat exchanger where the coolant is heated before
being returned to the engine coolant system. The warmed coolant is used to warm the diesel engine
head and cylinder block to promote cold weather starting.
The warmed coolant also passes through two hydraliner heating elements located in the main hydraulic
reservoir. These heating elements enable heat transfer from the warm coolant to the hydraulic oil in
order to improve cold weather operation of the crane's hydraulic components.
The coolant heater operates independently of the crane's diesel engine. It does, however, use 24-volt
DC power from the crane's electrical system as well as diesel fuel from the crane's fuel tank. The
coolant heater features a temperature regulating switch that controls the coolant temperature by
switching the unit on when the coolant temperature is below 154° F (68° C) and off when the
temperature is above 185° F (85° C).
The coolant heater control circuit includes a seven day timer mounted in the cab, a control unit, flame
sensor, temperature sensor, and an overheat sensor.
9.5 kW (32,400 BTU/hr)
7.5 kW (25,600 BTU/hr)
3.2 kW (10,900 BTU/hr)
1.5 kW (5,100 BTU/hr)
Diesel Fuel Consumption
0.32 gal./hr (1.2 l/hr)
0.24 gal./hr (0.9 l/hr)
0.11 gal./hr (0.4 l/hr)
0.05 gal./hr (0.2 l/hr)
20 to 30 VDC
Coolant Pump Flow
370 gal./hr (1400 l/hr)
Coolant Temperature Range
154-185° F (68-85° C)
Overheat Shutdown (Coolant Temperature)
240° F (115° C)
14.3 lbs (6.5 kg)