IK0900077 - IC Bus, Fuel Fired Engine Coolant Heaters

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IK0900077
ID:
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Availability: ISIS, Bus ISIS, IsSIR

Revision: 4

Major
System:

COOLING

Created:

12/5/2012

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Modified:

1/16/2019

Author:

Brandon
Akridge

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Title : IC Bus, Fuel Fired Engine Coolant Heaters
Applies To : AE, BE, CE, and RE Bus Models

CHANGE LOG
Please refer to the change log text box below for recent changes to this article:
1/16/19 - Added 17k Webasto (49WXD) to optional codes
07/17/18 - Update diog link
11/4/15 - Author updated for Feedback purposes
10/12/15 - Initial Article Release

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DESCRIPTION
Optional fuel fired engine coolant heaters may require the fuel system to be primed prior to use.
Option Codes:
49BRM
HEATER, ENGINE COOLANT Fuel Fired, Espar, 17,000 BTU, Mounted Forward of Rear Wheel Pocket, with Exhaust Exit Out left side, AFT
of Wheel Pocket
49WNS
HEATER, ENGINE COOLANT Fuel Fired, Espar, 17,000 BTU, With Exhaust Exit Ahead of Rear Axle
49EAS
HEATER, ENGINE COOLANT Fuel Fired, Espar, 42,000 BTU, with Exhaust Exit Ahead of Rear Axle
49GDM
HEATER, ENGINE COOLANT Fuel Fired, Webasto Scholastic, 45,000 BTU, With Exhaust Exit Under Rear Bumper
49GWX
HEATER, ENGINE COOLANT Fuel Fired, Webasto Scholastic, 45,000 BTU, With Exhaust Exit Out Left Side
49MRB
HEATER, ENGINE COOLANT Fuel Fired, Espar, 42,000 BTU, with Exhaust Exit Under Bumper, Mounted Aft of Rear Axle, Left Side
49WXD
HEATER, ENGINE COOLANT Fuel Fired, Webasto, 17,000 BTU, with Exhaust Exit Ahead of Rear Axle
The coolant heater fuel filter is filled during the manufacturing assembly process which allows sufficient fuel to test fire the unit. The test fire,
or operation validation process, will result in air in the fuel system as the fuel tank fuel level will be below the pickup tube level.
SYMPTOMS
• Unit will not start and run when received from the manufacturing.
• Repeated failed start attempts resulted in system shut down requiring system to be reset (Espar).
RESOLUTION

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IK0900077 - IC Bus, Fuel Fired Engine Coolant Heaters

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• Prior to validating fuel fired heater operation, remove fuel filter housing and fill with clean fuel.
• Ensure fuel tank is filled to above 1/4 of a tank.
• Reset system and timer as required by the manufacturer.
• Follow engine coolant heater manufacturer instructions to fire system.
• Once running, run unit for a minimum of 30­40 minutes to purge all air from the fuel system.
DIAGNOSTICS
• Depending on age of your bus, some units have different diagnostic ports and locations of those ports for troubleshooting. It is best to
consult the link below for the specific vendor to determine which you have.
• Some newer models may have simple USB conections, similar to the one shown below for newer Webasto timers.

NOTE:
Priming the fuel system would be considered part of the dealer pre-delivery process and would not be covered under standard warranty coverage.

ADDITIONAL RESOURCES
Espar:
Espar Diog.

Webasto:
Webasto Installation/Operation Instructions
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