RV Hydronic Heater Repair

 
Model
411

This model may also be known as:

 

411

 

Similar models

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.

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

 

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.

 

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.  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.

 

Pump may 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

Service Manual

 

AHE-100-02S - On Aqua-Hot website