Fluid Level Sensor
©Aqua-Hot®
250-D03 Diesel Series Service Manual
REV 220302
p. 22
ETS Module
ETS Module
The ETS (Engine Temperature Sensor) Module is a brass
thermistor that continually measures the temperature of the
fluid within the Aqua-Hot boiler tank. This module then relays
the information to the Aqua-Hot controller, thereby allowing the
controller to activate and deactivate the unit as heating and hot
water needs change.
Troubleshooting Conditions:
Troubleshooting the ETS module is a relatively straight
forward process. Follow the instructions below to diagnose
the ETS module. Troubleshoot the ETS module if the following
conditions have occurred:
• A lack of hot water.
• A lack of interior heat.
• The Aqua-Hot is not operating.
Troubleshooting:
1. Verify the following before troubleshooting the ETS
module:
• The Interlock Switch is depressed (access cover is
properly installed).
•
The overflow bottle is adequately filled.
• Ensure that DC electrical power is supplied to the
Aqua-Hot.
• Ensure that AC electrical power is supplied to the
Aqua-Hot’s electric element.
• The high-limit thermostats are not tripped.
• All fuses are in working order.
2. Turn the burner and/or electric element to the ON
position.
3. Using a meat thermometer, measure the temperature
of the tank face. Record this temperature on paper.
4. Locate the LCD screen or RV control panel. Navigate
to the DIAG page. Find INPUTS FROM AQUA-HOT and
record the temperature listed by TANK TEMPERATURE
(Figure 32). Record this number on the sheet.
5. If the temperatures do not match, disconnect the ETS
module from its leads on the wire harness.
6. Navigate back to the INPUTS FROM AQUA-HOT section
of the LCD/RV display screen.
• If the display screen does display a temperature,
the controller will need to be replaced.
• If the display screen does not show any temperature,
the ETS module will need to be replaced.
Figure 31
ETS Module
Figure 33
Figure 32
