Espar Hydronic S3 D5E CS Diesel 12V Heater RV Kit with EasyStart Pro Controller

Diesel Air and Water Heating Kit for RVs and Camper Vans

Built for diesel-powered RVs and camper vans, the Espar Hydronic S3 D5E CS uses fuel from the vehicle’s tank to provide cabin heating and non-potable hot water. Its continuously regulated 4,440–17,000 BTU/h output is paired with the compact Kalori EVO 1 blower for effective heat distribution without taking up unnecessary living space.

The included Kalori EVO 1 blower heater transfers heat from the coolant into the living space. A separate 24-plate heat exchanger with a mixing valve can transfer heat to a non-potable water circuit for applications such as washing or showering, subject to local requirements.

Key Benefits

• Uses diesel from the vehicle’s fuel tank
• Provides 4,440–17,000 BTU/h (1.3–5.0 kW) of continuously regulated heat
• Includes a Kalori EVO 1 blower heater for cabin heating
• Supports non-potable water heating through a separate plate heat exchanger
• Can operate independently or connect to the engine coolant circuit
• EasyStart Pro provides heater control, timers and diagnostics
• Supports operation up to 9,900 ft (3,000 m) with high-altitude mode
• Compact heater can be installed outside the living area
• Fully customizable for different RV heating requirements

Fully Customizable Hydronic Heating

The D5E provides a flexible foundation for a custom RV hydronic system. Additional water-to-air heat exchangers, hydronic radiators, floor-heating loops and separate heating zones can be added when correctly sized and installed.

The system may also be configured for engine preheating or for using engine heat while driving. Additional pumps, valves, manifolds, thermostats and control components may be required.

All heating elements share the Hydronic’s maximum 17,000 BTU/h (5 kW) output. Adding more heating zones improves heat distribution but does not increase the total available heating power.

How the System Works

The D5E burns diesel to heat a water-glycol coolant mixture. An external circulation pump moves the hot coolant through the Kalori cabin heater, plate heat exchanger and any optional heating elements.

The primary coolant and secondary water circuits remain separate and do not mix. The supplied 5-liter tank is an expansion tank for the closed coolant circuit—not a hot-water storage tank.

Non-Potable Water Notice: The included plate heat exchanger is intended for non-potable water applications. Water heated through this component must not be used for drinking, cooking or food preparation. Confirm applicable requirements before using the system for washing or showering. A certified potable-water heat exchanger and compatible plumbing components are required for potable hot water.

Technical Specifications

• Fuel: Diesel
• Voltage: 12V
• Heat output: 4,440–17,000 BTU/h (1.3–5.0 kW)
• Maximum output: approximately 17,000 BTU/h
• Maximum fuel consumption: 0.59 l/h (0.16 gal/h)
• Hydronic electrical consumption: approximately 5–32 W
• Power consumption during startup: approximately 135 W
• Coolant pump consumption: approximately 17 W
• Minimum coolant flow rate: 300 l/h (79.2 gal/h)
• Kalori EVO 1 blower consumption: up to 70 W
• Maximum operating altitude: 9,900 ft (3,000 m)
• Heater dimensions: 215 × 91 × 144 mm
• Heater weight: approximately 2 kg
• Kalori EVO 1 heating capacity: approximately 4.3 kW

Part numbers:

• Complete kit: 2528293405000 + RV kit accessories 
• Heater only: 252652050000
• Alternative formats: 25.2829.34.05000; 25.2829.34.05.000; 25 2829 34 05000; 25 2829 34 05 000

Browse Eberspächer/Espar Manuals & Technical Documentation

Included in the Kit

• Diesel Espar Hydronic S3 D5E 12V Heater
• EasyStart PRO controller
• Pre-assembled 24 plate Water heat exchanger with mixing valve
• Kalori Blower controller unit
• Kalori Blower box 4.3KW with Grill
• 5 Liter water expansion tank
• Fuel Pump
• 1m of exhaust pipe
• 1m of combustion Intake pipe
• 4m of water hose 16mm ID (Blower Box)
• Circulating Water Pump (for glycol / coolant)
• All electrical harnesses and connections
• All necessary clips and screws
• Hydronic Mounting Bracket

Vehicle-specific fuel, coolant, exhaust and installation components may be required. Professional installation is recommended.