Coolant heaters act as a heat exchanger,
using the on-board fuel supply and 12- volt batteries to run them independently without requiring a block heater plug-in. It requires a hard-wired ignition, a fuel source and flow throughout the system. Te engine cooling system is connected
to the heater, which uses a low-amp draw for the ignition and fuel pump to ignite the heater initiated by a glow pin. Once the flame is established, the glow pin shuts off while the flame continues until it is manually turned off by the operator or automatically shut down by the program- mable timer. Te integral water pump circulates
the coolant over the heat exchanger and heats the coolant. Te hot coolant then flows through the engine block, gradual- ly heating up the cooling system. All the major components, including the elec- tronic controls, water pump, fuel pump and safety sensors, are integrated into the heater to reduce overall size and the time it takes to install the unit. “A coolant heater for a school bus is re-
ally a win-win situation for the fleet. Te heater will pay for itself in fuel savings alone, but will also save the fleet addi- tional money on maintenance and labor costs. No winter start-up crew is needed, and the windows are defrosted for a clear and safe review of the road. Passengers are warmer and emissions are greatly re- duced, allowing fleets to abide by idle restriction rules,” said Paula Bishop, man- ager of transportation and environmental affairs at Espar Heater Systems.
WHAT OPTIONS ARE AVAILABLE?, For heat output, coolant heaters are
rated in British Termal Units, which can range from 8,000 to 45,000 BTUs. Te se-
With winter around the corner, student transporters are reminded of the importance of heaters to start the bus and to keep both the students and drivers warm.
verity of a winter climate and school bus size will determine the size of the heater. Te higher BTU output will obviously in- crease the heater dimensions, weight, fuel consumption and amperage draw. How- ever, these differences are not substantial and depend on what model of coolant heater is chosen. Coolant heaters also run on gas and biofuel, so they can be adapted to a variety of bus models. Different operating switches and con-
figurations can also be implemented to suit any kind of cold weather climate. One option is an additional switch mounted on the dash that allows drivers to manual- ly keep the interior temperature constant while you are sitting idle operating a spe- cial needs bus, which loses accumulated interior heat while the wheelchair lift door is open. “Recovery interior-heat time is greatly
reduced. Tis is especially important within special needs transportation when a wheelchair lift door can be opened for a period of five minutes or longer,” said Paul Baczewski, national account manager for Webasto Product North America, Inc. “We are very happy with our cool-
ant heaters. We use them on our special education buses to help keep the engine temp up to operating range, prevent- ing cooldown when the bus is idling at a wheelchair stop. Te higher engine temp also helps with the re-gen process,” added Jim Shafer, manager of contractor School Bus, Inc., in Sioux Falls, S.D. Shafer’s team uses these heaters on mo-
torcoaches when they are out of town on overnight trips in the winter time. “You can turn on the heater and the bus will start easily within 90 minutes,” he said. “Tis is a huge fuel savings compared to
Monitoring School Bus Heaters How would a fleet owner know if all the coolant heaters are working and for what amount of time each day? Phil Downs, fleet
services supervisor for Columbus City Schools in Ohio, operates 543 buses equipped with retrofitted coolant heaters with Zonar GPS tracking, which allows him to access daily reports to see which buses are getting pre-heated and what time heaters come on. Knowing about a faulty heater ahead of time allows him to send out a crew to get a bus going before the run. Downs also said the coolant heaters can be operated while the bus is shut down at a school. He added that less engine idling time in cold tem- peratures results in substantial savings on fuel and manpower. He was unable to provide exact data on fuel savings, but during a cold snap earlier this year, he said his 543 buses idled for two hours for 15 days straight for a total of 16,290 hours of idling time. “We also save on (overtime) because our starting crews do not need to come in as early,” said Downs.
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