The pump circulates coolant through the heater and the connected heating circuit. Proper coolant flow allows heat produced by the Hydronic heater to be transferred to the engine, cab, passenger compartment or another connected heat exchanger.

Part 252219250000 is also formatted as Eberspächer part number 25.2219.25.0000. The complete assembly includes the pump housing and two replacement O-rings.

This pump has 18 mm outside-diameter coolant connections. Applications requiring a 20 mm connection may use a different pump, so the existing hose and pump dimensions should be confirmed before ordering.

The pump is designed for specified 12V Hydronic D4WSC, D5WSC, B4WSC and B5WSC heater configurations. Compatibility depends on the heater’s complete identification number.

Related service components include the 201819991600 combustion-air blower, 201820990001 burner and blower gasket set, 252216100000 Hydronic burner, 252121990113 glow-pin lining and 252106011300 12V glow pin.

Always confirm the heater model, voltage, identification number and coolant connection size before ordering.

Key Features

• Complete coolant-circulation pump assembly
• Designed for compatible Hydronic coolant heaters
• 12V electrical configuration
• Includes the pump housing
• Includes two replacement O-rings
• 18 mm outside-diameter coolant connections
• Fits specified Hydronic D4WSC applications
• Fits specified Hydronic D5WSC applications
• Compatible with specified B4WSC and B5WSC heaters
• Supports coolant circulation through the heating system
• Suitable for heater repair and coolant-system service

Specifications

• Part Number: 252219250000
• Formatted Eberspächer Number: 25.2219.25.0000
• Product Type: Water pump / coolant-circulation pump
• Voltage: 12V
• Coolant Connection Outside Diameter: 18 mm
• Primary Function: Circulates coolant through the heater system
• Heater Type: Fuel-operated coolant heater
• Heater Family: Hydronic
• Compatible Model Families: D4WSC, D5WSC, B4WSC and B5WSC
• Installation Location: Heater coolant circuit
• Housing Included: Yes
• Replacement O-Rings Included: Two
• Brand: Eberspächer/ESPAR
• Condition: New replacement part
• Unit of Measure: Each

Compatible Eberspächer/ESPAR Heaters

Part 252219250000 is identified for compatible 12V versions of:

• Hydronic D4WSC
• Hydronic D5WSC
• Hydronic D5SC
• Hydronic B4WSC
• Hydronic B5WSC
• Other Hydronic heaters specifically requiring water pump 25.2219.25.0000

Known compatible heater numbers include:

• 201824050000
• 201821050000
• 201820050000
• 201823050000
• 252219050000
• 252257050000
• 252221050000
• 252229050000
• 201861050000
• 252385050000
• 201863050000
• 252390050000

Compatibility should be confirmed using the heater identification label and complete heater number before ordering.

This pump should not be assumed compatible with:

• 24V Hydronic heaters
• Hydronic S3 heaters
• Hydronic M-II heaters
• Applications requiring 20 mm coolant connections
• Applications requiring water pump 251920250000
• Heaters that have not been positively identified

Common Service Applications

The water pump may require replacement when:

• The pump does not operate
• Pump operation is intermittent
• Coolant does not circulate through the heater system
• Electrical testing identifies a pump failure
• The pump housing or electrical connection is damaged
• Coolant leakage is traced to the pump assembly
• The heater shuts down because of insufficient coolant circulation
• Heating performance is affected by inadequate coolant flow
• The coolant system is undergoing repair
• A technician has diagnosed the water pump as the failed component

A heater shutdown or coolant-flow problem does not automatically confirm pump failure. The wiring, electrical connection, coolant level, trapped air, hose restrictions and other system components should also be inspected.

Important Installation Notes

• Confirm that the heater operates on 12 volts.
• Confirm the complete heater model and identification number.
• Verify that the application uses 18 mm coolant connections.
• Do not substitute a 24V water pump.
• Disconnect electrical power before beginning service.
• Allow the heater and coolant system to cool before disassembly.
• Drain or isolate the coolant circuit as required.
• Inspect the electrical wiring and pump connection.
• Inspect the coolant hoses for damage, deterioration or restrictions.
• Inspect the supplied O-rings before installation.
• Confirm the correct direction of coolant flow.
• Install the pump in the required position and orientation.
• Use compatible coolant hoses and connection components.
• Secure all coolant connections before refilling the system.
• Refill the circuit with the approved coolant mixture.
• Bleed trapped air from the coolant system.
• Check the pump and coolant connections for leaks.
• Test coolant circulation and heater operation after installation.
• Service should be performed by a technician familiar with Hydronic coolant heaters.

Related Products

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• 201820990001 – Eberspächer/ESPAR Hydronic D4/D5 Burner and Blower Gasket Set
• 252216100000 – Eberspächer/ESPAR Hydronic D4W/D5W Burner
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• 252106011300 – Eberspächer/ESPAR Hydronic D4WSC/D5WSC 12V Glow Pin
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• 225201040011 – Eberspächer/ESPAR Hydronic D5 12V Control Unit
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