RV Hydronic Heater Repair
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.
Thermostats are ELX-560-213, which are no longer available. Upgrade kit is here: ELX-560-213
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.
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.
Recommended Service Parts to Keep On Hand
Filter: VERIFY FILTER: Normally one of filters below.
Webasto - WPX-603-359
Racor R12T FLE-R12-TRA
Optional Service Parts to Keep On Hand
AHE-100-02S - On Aqua-Hot website