RV Hydronic Heater Repair
AHE-100-02S
This model may also be known as:
920/431, 920431/12, 920/432, 431
Most of these heaters were 12-volt,
however there were a few 24-volt heaters built.
This model of Aqua-Hot uses 'standard' ethylene glycol coolant (Prestone or equal). Keep it simple and use the same coolant that is in your engine and generator.
Changes From Previous Model
This model is almost identical to the 431 model after serial number 98571
Part Notes
Diesel Control (Blue Dot) ELE-L08-190
Diesel High Limit (Black Dot) ELE-L08-230
Electric Control (Red Dot) ELE-010-198
Electric High Limit (White Dot) ELE-254-010
3 zones + engine circulation pump PLX-809-200 Pump parts (scroll down - these parts are near the bottom of the page)
1650 watt electric element ELX-2E7-540 Note: that electric element rarely fails!
Most failures in electric system is electric high limit thermostat.
Mixing valve (complete) PLX-4A8-180 - Rebuild kit PLX-4A8-18R
Radiator Cap - PLX-102-229 or with lever PLX-102-229-L
Common Problems
Pumps develop leaks, which require replacement of "O" rings. March Pump "O" Ring You have to remove pump to disassemble it to replace "O" ring.
Radiator cap should be replaced at least every other year (or as often as needed). PLE-102-229 or Cap with Lever PLE-108-229-L
Routine Maintenance
Replace filter and nozzle when exhaust gets smoky / smelly. Aqua-Hot recommends yearly routine service.
Pumps develop leaks, which require replacement of "O" rings. March Pump "O" Ring You have to remove pump to disassemble it to replace "O" ring.
Radiator cap should be replaced at least every other year (or as often as needed). PLE-102-229 or Cap with Lever PLE-108-229-L
Recommended Service Parts to Keep On Hand
Filter: VERIFY FILTER: Normally one of filters below.
Webasto - WPX-603-359
Racor R12T FLE-R12-TRA
Nozzle: WPX-886-41A
Optional Service Parts to Keep On Hand
None