RV Hydronic Heater Repair



This model of Aqua-Hot uses the special Camco -100 Boiler coolant.




This model may also be known as:


AHE-450-DW3, AHE-450-D04

Changes From Previous Model


Tank level sensor is new design


  • Combustion chamber has been redesigned. 
  • Combustion chamber now looks like this:
  • You need to replace gasket if you remove combustion chamber, here HDE-700-205

    Pump Information


    There were at least 4 different types of pumps used in this model.


    Zone Pumps, here:  400 Series Zone Pumps

    Stir Pumps, here:   400 Series Stir Pumps

    Engine Preheat Pumps, here:   400 Series Engine Preheat Pumps

    Part Notes


    • Control Thermostat -   ELE-014-010
    • Expansion Tank, 3 QT (Zero Pressure System)  - PLE-070-401

    • Interlock Switch - ELX-000-050

    • Diesel High Limit Thermostat - 215°F w/Spade Connectors - ELE-HLT-425

    • Electric High Limit Thermostat VAC 215°F - ELE-HLT-424

    • Electric High Limit Thermostat - 215°F with terminals crimped on - ELE-000-616-FRU

    • Thermostat, Low Temp Cut-Off w/Spade Connectors - ELE-LTC-608

    • Control Board -  ELE-PC4-010 
    • Zone, stir and engine preheat pumps (are no longer available).  Pump upgrade kit, here: PLE-100-905-FRU
    • Radiator cap - None Used.  Zero Pressure System
    • Brand New Webasto Burner - WPE-909-180
    • Reconditioned Webasto burner - WPE-909-180-R


    Information on tank level sensors    Tank Level Sensor Information


    Routine service parts and kits - Routine Service Parts      Scroll down page for filter and nozzle packages.



    Common Problems


    • The PLX-100-850 pumps have not held up well.  Replace with this kit:  PLE-100-905-FRU

    Service Manual


    On Aqua-Hot website   AHE-450  Use Service Manual for AHE-450-DE4