Introduction
Introduction
©Aqua-Hot®
125-DN1 Service Manual
REV 220421
©Aqua-Hot®
125-DN1 Service Manual
REV 220421
p. 3
p. 2
Contents
Caution Notes ...............................................................................2
Introduction ..................................................................................3
Maintenance Schedule ................................................................6
System Features ..........................................................................7
Component Cut-Aways .................................................................8
Operational Flowchart................................................................10
Operating the LCD ......................................................................11
Aqua-Hot Controller .................................................................. 13
Controller Replacement Procedure
17
Fluid Level Sensor ..................................................................... 20
High-Limit Thermostats............................................................. 22
Low-Temperature Cutoff Thermostat........................................24
Three-Way Valve ........................................................................ 25
Tempering Valve .........................................................................27
Fluid Circulation Pump .............................................................. 29
AC Electric System......................................................................31
AC Relay ..................................................................................... 33
ETS Module ............................................................................... 34
High Altitude Replacement ....................................................... 36
Fuel Purge Procedure ............................................................... 39
First Operation after Service .................................................... 40
General Troubleshooting............................................................41
Winterization.............................................................................. 42
Burner Troubleshooting ............................................................ 43
Appendix A: System Schematics .............................................. 45
Appendix B: Parts .......................................................................51
Appendix C: Measuring Antifreeze ........................................... 55
System Overview
The Aqua-Hot 125DN Series is a Hydronic Heating System
that can provide heat and hot water on demand using a built-in
electric heating element and an external diesel burner.
The Aqua-Hot Heating is a 2-in-1 System
1. Interior heating system: provides quiet, comfortable interior
heat and even temperatures.
2.
Tank-less hot water system: provides a flow of comfortable
hot water.
The Aqua-Hot heating system heats an ethylene
glycol-
based antifreeze (50%) and distilled water solution (50%) that
is stored in the Aqua-Hot’s boiler tank. This fluid solution must
be up to operating temperature before the Aqua-Hot will provide
interior heat or hot water. The tank-less hot water system
produces approximately 0.8 GPM of hot water. This system is
also hot water priority, so it will shut off the heat any time hot
water is called for.
Once the fluid is to temperature (180°F), a fluid circulation
pump transports the heated glycol/water mixture through the
heating loop and to heat exchangers to evenly warm the coach.
Water is heated on-demand by going into a heat exchanger
located in the Aqua-Hot. The water is heated by transfer from
the heated antifreeze and distilled water solution. The heated
domestic water then flows through the tempering valve to be
mixed with cool water from the fresh water tank to achieve an
appropriate temperature before it flows to the faucet.
To get the Aqua-Hot to temperature, turn the electric heating
element and/or the external diesel burner to the “ON” position
on the Aqua-Hot LCD screen, or on the coach control panel.
It may take up to 20 minutes to get to operating temperature
before heat or hot water are available.
For continuous hot water or heat in colder conditions, it is
recommended to utilize the external diesel burner. The electric
heating element will provide heat only in mild conditions and
provide light duty hot water needs.
Should additional assistance be needed, please contact the
Technical Support at 574-AIR-XCEL (574-247-9235), Monday
through Friday, between 7:00am and 4:00pm MST.
Figure 1
Diesel Burner
Cozy #1
Living Space
Aqua-Hot
Heating System
Cozy #2
Kitchen
Cozy #3
Bedroom
NOTE:
The image below is just a sample for mounting locations
of the Cozy heat exchangers, burner, and Aqua-Hot. Actual
placement and quantity may vary on the individual design of the
RV. For questions or assistance, contact Aqua-Hot at 574-AIR-
XCEL (574-247-9235).
Caution Notes
As you read this information, take particular note of the NOTICE,
CAUTION, WARNING, and DANGER symbols when they appear.
This information is important for safe and efficient use of the
Aqua-Hot system.
NOTICE
signals a situation where potential damage to the
Aqua-Hot could occur.
CAUTION
signals a situation where potential harm or risk of
minor or moderate injury could occur if you do not follow
instructions.
WARNING
signals a hazardous situation where potential harm,
risk of serious injury, or death could result if instructions are not
followed.
DANGER
signals a situation where immediate risk of serious
injury or death will result if instructions are not followed.
NOTE:
This manual will also use notes sections similar to
this one to draw attention to features and practices which
must be observed.
