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 may be 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.
Notes and Description of this Model
This model is based on the heaters in the 431 series.
There is ONE zone pump. When any zone calls for heat, the one zone pump runs (heating both zones). The interior heat exchanger fans would only run in the zone(s) that are turned on inside.
There is no engine preheat pump, however the engine coolant will run through the unit, heating the boiler tank as you drive.
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
1 zone pump. Not stocked, but available.
1650 watt electric element ELX-2E7-540 Note: that electric element rarely fails!
Most failures in electric system is electric high limit thermostat.
Pumps develop leaks, which require replacement of "O" rings. You have to remove pump to disassemble it to replace "O" ring.
Replace filter and nozzle when exhaust gets smoky / smelly. Aqua-Hot recommends yearly routine service.
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