Aqua-Hot: 125-D02 Use and Care Guide

Important Notes:

• A qualified installer or service technician must perform equipment installation or service. Contact Aqua-Hot for Factory Authorized Service Centers or Certified technicians located near you at www.aquahot.com/service-help, or call us at 574-AIR-XCEL (574-247-9235).
• Warranty work must be performed by an Aqua-Hot Factory Authorized Service Center.
• Your on-product identity label contains the specifications of your unit. Factory settings may be adjusted by the vehicle manufacturer, confirm final setting with your dealer.

• Follow this guide exactly. Failure to do so may result in a fire or explosion resulting in property damage and/or personal injury.

Journey in Comfort

Comfort Zone #1: Comfortable Cabin Heat

• Get heat where you want it, when you want it. This Aqua-Hot system puts heat where you need it. Therefore, your interior temperatures will be just right. Don’t hesitate to crank up the heat because the Aqua-Hot system doesn’t remove moisture from the air. From now on, you will have to blame the dry skin and itchy eyes on Mother Nature!

Comfort Zone #2: Quiet Operation

• Say goodbye to rude awakenings from the forced air furnace, you’re an Aqua-Hot owner now! The Aqua-Hot is quiet when operating, so you’ll never have to turn up the TV, yell across the room, or have an interrupted night of sleep again due to your heating system.

Comfort Zone #3: Comfortable Hot Water

• Take showers knowing that your tank-less Aqua-Hot is ready and waiting to deliver hot water. The freedom to take a hot shower when you want makes your experience much more like home.

Comfort Zone #4: Low Emissions

• Aqua-Hot’s new low emission systems are fume-less and odorless. It’s good for you, good for your neighbor, and good for the environment.

Comfort Zone #5: Large Service Networks

• You won’t need to service your Aqua-Hot often, but when you do, you can be confident in our Certified Service Centers that are close by and trained to assist you with all of your Aqua-Hot specific needs.

Comfort Zone #6: Adds Value

• The NADA Recreational Vehicle Guide lists Aqua-Hot as adding thousands of dollars to the value of a RV or caravan. That value will pay off when it’s time to trade up or sell.

Comfort Zone #7: Low Fuel Costs

• There’s no need to burn fuel each time heat or hot water is needed. The Aqua-Hot heats a boiler tank and uses the heat stored in the liquid of the boiler tank to provide interior heat. Aqua-Hot’s 100 Series uses TribridHot™ technology to power the Aqua-Hot system by pulling heat from one or a combination of heat sources. Use the electric setting to keep the boiler tank up to temperature and for light heating needs. Use the burner when colder conditions require or when using hot water.

Introduction

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.

Safety Instructions

Read all instructions before using the Aqua-Hot unit. Aqua-Hot Heating Systems is not liable for damage resulting from failing to follow instructions contained in this, and any other Aqua-Hot documentation relevant to this unit.

• Read this user manual before using the Aqua-Hot System to reduce the risk of injury to persons or damage to the equipment.
• The product identity label contains specifications of the unit, to what standard it has been tested, and important safety notices.

• Disconnect electric wiring to the Aqua-Hot System before welding or plasma cutting the RV to avoid damage to equipment.
• The Aqua-Hot tank and heating loop operate at 7.0 PSI. Maximum testing air pressure to the tank must not exceed 18 PSI. Exceeding this rating will cause internal damage to the Aqua-Hot.
• DO NOT connect the 12-volt DC power to the Aqua-Hot if the vehicle requires welding.
• At maximum operating temperature, the coolant will be very hot and scalding hot vapor or coolant may result in serious burns or injury. Be aware of hot surfaces.

• Use special caution when children are present. Children must not be allowed to play with the heater or perform cleaning and maintenance.
• At maximum operating temperatures, the hot air outlet will be very hot that may result in serious burns or injury. Be aware of hot surfaces.
• The burner produces very hot temperatures that can ignite surrounding flammable materials. The burner should be turned off when loading or unloading flammable materials

Note: Aqua-Hot recommends regular exercise of the Aqua-Hot heating system to avoid issues with starting after a several-month idle period.

Safety Features

Low-Voltage Shutdown

The Aqua-Hot Controller is designed to operate between 11V DC and 16V DC. If the Controller detects that it is receiving voltage below 11.8V DC, a System Voltage fault will trigger a display on the LCD screen. If the Controller system drops below 11.2V DC for 30 seconds, it will discontinue operation of the Aqua-Hot heating system.

Over-Current

An Over-Current fault condition occurs when too much current is drawn by a component, usually a fan or pump. When this fault is triggered, the output channel is shut off until the system has been reset or power-cycled.

Over-Temperature

An over-temperature fault will occur if your Aqua-Hot heating system has reached 218° F. The Controller will deactivate the heater and display an over-temperature fault on the LCD display screen.

Low-Level Cutoff

If the system senses low fluid levels, the heating system will shut down all fans, heat sources, and pumps until the unit is adequately refilled.

WARNING!

Read and understand all instructions before using the AquaHot unit and the external diesel burner. Aqua-Hot Heating Systems is not liable for damage resulting from failing to follow instructions contained in this, and any other Aqua-Hot documentation relevant to this unit. Improper installation, operation, adjustments, service, and maintenance can cause personal injury or loss of life. Reference this Use & Care Guide before operation.

Note: Contact your Authorized Service Center or Aqua-Hot Heating Systems if you have any questions before starting any operation, service, or maintenance. Information can be found online at Aqua-Hot.

Safe Operation 

The Aqua-Hot Heating system consists of an electric heating element and an external diesel burner. The electric element and/or the external diesel burner heat an ethylene glycol and water mixture, that flows through tubing and into heat exchangers to heat a zone that calls for heat. The heating system also heats domestic water for hot water use in the shower or at hot water faucets.

Locate the Aqua-Hot LCD screen (shown below) inside the RV (contact the vehicle manufacturer if unable to find), tap the screen to wake, tap on either the “ELECTRIC” to turn on the Electric Element or “BURNER” to turn on the external diesel burner. It will take approximately 20 minutes to get the glycol fluid up to operating temperature. After the tank is to temperature, you can turn on the heat on your RV thermostat or run hot water.

General Care

The Aqua-Hot AHM-125D’s fluid levels should be checked regularly to ensure it is at the proper level. It should be checked when the Aqua-Hot is at maximum operating temperature - when the external diesel burner completes a cycle or when the electric element disengages.

It is necessary to take precautions during any user maintenance. Note that the fluid will be very hot, and any scalding hot vapor or coolant could cause serious burns or injury.

Intended Use

This manual explains the operation and care of the Aqua-Hot heating system and controller. These instructions are approved for the Aqua-Hot AHM-125D model for recreational vehicles only. Not for use in boats.

Service and repairs may only be carried out by an authorized, factory-trained Aqua-Hot technician. The heating system must be installed/serviced in accordance with local codes, or, in the absence of local codes, follow NFPA 1192.

• The vehicle owner is responsible for correct operation of the appliance.

• The Aqua-Hot AHM-125D must comply with the codes and regulations of the country it is being used in. National and local codes must be followed, or follow NFPA 1192.

• Make sure to properly winterize the Aqua-Hot’s domestic water system when not in use and/or any time the heater is stored where freezing temperatures may be experienced. The Aqua-Hot warranty will not cover claims for freeze damage. Please refer to page 16 for proper winterization of the Aqua-Hot.

• In order to provide the best freeze protection, boil-over protection, anti-corrosion, and rust protection, a mixture of 50/50 Ethylene Glycol antifreeze and distilled water is recommended. The Aqua-Hot AHM-125D boiler tank holds approximately 2 gallons. See page 15 for info.

Component Callouts

Aqua-Hot System Features

System Features

The Aqua-Hot AHM-125D 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 System 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 uses one or a combination of the following heat sources:

• When plugged into shore power, or powered by a generator, the electric element lets you use the power you are already paying for to provide heat in mild conditions and meet your light duty hot water needs.
• The external diesel burner can be utilized with the Aqua-Hot to heat and produce hot water.

Bring the Aqua-Hot to Operating Temperature:

Your Aqua-Hot hydronic heating system heats an ethylene glycol antifreeze and distilled water solution that is stored in the Aqua-Hot’s boiler tank. This water and antifreeze solution must be up to operating temperature before the Aqua-Hot will provide interior heat or comfortable hot water. To bring the Aqua-Hot up to temperature, navigate to the climate page of the LCD screen, and tap either the “ELECTRIC” or “BURNER” icon. Depending on the ambient temperature, it may take up to 20 minutes for the Aqua-Hot’s water and antifreeze solution to reach operating temperature.

Once the tank is up to operating temperature, the electric element may be used to maintain the operating temperature and provide light duty hot water and interior heat.

For continuous hot water, or for heat in colder conditions, it is recommended to utilize the external diesel burner.

Operational Overview

The heating features are powered by the external DC diesel burner and/or the AC electric element on the AHM125D. These maintain the temperature of the Aqua-Hot’s antifreeze and water heating solution to provide hot water and interior heat.

External Diesel Burner:

The diesel burner is the Aqua-Hot’s primary and most powerful heat source, and provides all of the heating and hot water needs when cold temperatures exist, and/ or when there is a high demand for hot water. It can be activated by tapping BURNER to ON on the LCD screen shown below.

The burner has 2 modes: ON and OFF. When the burner is ON, the burner will keep the tank temperature between 160°F and 180°F. The burner will toggle between ON and OFF as needed, using temperature readings from the RV interior thermistors. In OFF mode, the burner is off and will not provide any heat to the Aqua-Hot tank.

Electric Element:

The electric element is the Aqua-Hot’s secondary heat source and can be used when plugged into shore power. The electric element will work to maintain tank temperature at 5°F below the heater activation threshold. It can be activated by tapping on the ELECTRIC button of the LCD screen interface.

The electric element has 2 modes: ON and OFF. When the electric element is ON, the electric element will keep the tank temperature between 165°F and 180°F. The electric element will toggle between ON and OFF as needed, using temperature readings from the RV interior thermistors. In OFF mode, the electric element is off and will not provide any heat to the Aqua-Hot tank.

Controlling Heat Levels with Room Thermostat:

When the Aqua-Hot is on and up to operating temperature, adjust the room thermostat to the desired temperature and it will automatically activate the Aqua-Hot’s heating functions to maintain the desired interior temperature. Different manufacturers may use different types of thermostats. Please contact the dealer or manufacturer for the exact type, location, and thermostat operation.

Aqua-Hot 3.5in. LCD Display

The Aqua-Hot electronic display provides direct diagnostics and control of the Aqua-Hot. This display is directly interfaced with the Aqua-Hot to relay real-time operational information such as unit diagnostics, warnings, faults, and operating conditions. Please contact Aqua-Hot, or your vehicle manufacturer, for more information.

Using Hot Water:

When hot water is requested, domestic water from the RV’s fresh water tank is transported through the domestic water line, that goes into a heat exchanger located in the Aqua-Hot. The water is then 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.

Heat Priority Option:

The Aqua-Hot comes equipped with a three-way valve (sometimes known as the summer/winter valve). This controls the flow of the antifreeze and water heating solution within the Aqua-Hot to deliver either hot water or interior heat as priority. Tapping on this element will change the valve’s orientation. When this element is activated, it overrides the automatic function and orients the valve to interior heat. When the element is not activated, the unit is in automatic mode and the valve is automatically oriented based on the Low-Temperature Cut-Off.

Operating the LCD & Aqua-Hot

This section will outline the basic operating instructions for the Aqua-Hot LCD Screen.

Climate Pages:

The climate pages are for all intents and purposes the “Home” of the LCD screen. From here, the end-user will select their interior temperature set-points, activate or deactivate the diesel burner and/or the electric element.

Zone Control [1] [1A]

Precise zone control display will differ depending on the type of zone thermostats/thermistors used within the RV.

Section 1A demonstrates the appearance of the zone control section when ON/OFF thermostats are used within the RV. In this use-case, these buttons serve only as ON/OFF toggle switches.

Section 1 demonstrates the appearance of the zone control section when thermistors are used. Tapping on one of the zones shown above will display a new screen where the interior temperature can be set.

Section A

This section shows the current zone temperature (shown as 71°F in the example above) as well as a button to turn the zone on or off. (Setting specific temperatures can only be done if thermistors are installed. Thermostats would only show ON/OFF.)

If the zone temperature is set, but this item is not set to ON, the zone heat exchanger will not activate.

Section B

These arrows are used to increase or decrease the desired set-point temperature of the zone thermistor.

Section C

After the desired temperature set-point has been selected tap “SET” on the LCD to set that temperature. The Aqua-Hot will now work to maintain this interior temperature, and the screen will return home.

External Diesel Burner Activation 2

The external diesel burner of the Aqua-Hot can be activated by tapping on the “burner” item on-screen. The diesel burner has two modes: ON and OFF.

ON:

While set to ON, the Aqua-Hot burner will work to maintain a tank temperature of 180° F.

OFF:

While off, the burner will not serve to provide any heat to the boiler of the Aqua-Hot whatsoever.

Electrical Element Activation 3

Similar to the external diesel burner, tapping this button will signal to the controller to activate the AC electric relay, energizing the 1500W electric element within the Aqua-Hot. The electric heating element has two modes: ON and OFF.

ON:

While set to ON, the electric element will work to maintain a tank temperature of 180° F.

OFF:

While off, the element will not serve to provide any heat to the boiler of the Aqua-Hot whatsoever.

Operating the LCD

System Status 4

This item will indicate the current operational status of the Aqua-Hot. If any faults have triggered, those will be displayed here.

During normal operation, this should display either INTERIOR HEAT or HOT WATER relating to the priority and position of the 3-way valve.

While in INTERIOR HEAT mode, the 3-way valve is oriented so as to circulate heated antifreeze and water solution through the heating zones of the RV.

While in HOT WATER mode, the 3-way valve is oriented so that the heated antifreeze and water solution is circulated immediately back into the boiler tank. This is known as “stirring” the tank, and it is done to provide as much heat as possible to the domestic water line while water is flowing.

Module Options 5

Tapping on the module options screen (the 3 lines on the bottom right of the home screen) will display the screen shown above. This is known as the Module Options screen. From here, it is possible to access unit diagnostics, activate Quiet Mode, change the temperature units, adjust screen brightness, and unit timeout.

Screen Timeout A

The screen timeout item sets the amount of time required to allow the screen to shut-off when idle.

Screen Brightness B

This setting changes the screen brightness.

Unit of Measurement C

This setting will change the display units of the AquaHot. Either Fahrenheit or Celsius can be selected.

Diagnostics D

Tapping on this element will direct you to the Aqua-Hot’s built-in diagnostic, testing, and troubleshooting tools.

Quiet Mode E

This option toggles the Aqua-Hot’s quiet mode. Quiet mode is a setting where the speed and output of the heat exchanger fans is reduced to 80%. This is done to reduce noise of the heat exchangers.

Please note that this feature must be activated and deactivated as needed.

Aqua-Hot Layout

Operational Flow Chart

Maintenance Schedule

Annual Maintenance

Check the Aqua-Hot’s antifreeze and water heating solution to ensure that it is at the proper level about once a year. Please note that the coolant level should ONLY be checked when the Aqua-Hot is completely cold.

To maintain the Aqua-Hot at its full potential, it is highly recommended to have the diesel burner tuned up annually. This involves replacing the fuel filter, cleaning the burner, inspecting the exhaust and combustion air lines for damage and ensuring they are clear, checking the fuel lines for any leaks, and checking the hoses and wiring to make sure there are no damage or cracks.

Replenishing the Heating Solution

If the antifreeze and water heating solution needs replenishing, remove the boiler tank cap and fill it. Replace the cap when this is complete. DO NOT operate the unit without first replacing the cap of the tank.

The Aqua-Hot does not need regular replacement of the antifreeze and water heating solution, but in the event that more antifreeze is required, contact Aqua-Hot Heating Systems to purchase antifreeze, or for guidance in selecting an appropriate antifreeze product for use with this unit.

Overheat Protection

Every Aqua-Hot is equipped with an overheat protection device. This is commonly known as the high-limit thermostat. This thermostat operates by maintaining a circuit while the unit is below 218°F.

In the event of an overheat condition, the high limit thermostat will cut the operating signal to the external diesel burner, and/ or the electric element. When this signal is interrupted, the electric element and diesel burner will immediately disengage. Contact Aqua-Hot Heating Systems for assistance in locating a qualified person to service this heater.

In order to provide the best freeze protection, boil-over protection, anti-corrosion, and rust protection, a mixture of 50/50 ethylene glycol antifreeze and distilled water is recommended. The AquaHot AHM-125D boiler tank holds approximately 2 gallons.

The mixture may be modified to provide the most adequate freezing, boiling, and rust/anti-corrosive protection. A 50/50 mixture of ethylene glycol and distilled water has a freeze point of approximately -35°F and a boiling point of approximately 223°F. Refer to the table below to determine the best protection mixture ratio and also reference page 20 for the proper tool and instructions for use in measuring the system’s antifreeze mixture ratio.

Winterizing the Aqua-Hot

The Aqua-Hot’s domestic water heating system must be completely drained of domestic water at any time the heater is stored where freezing temperatures may be experienced. Please follow these instructions when winterizing the Aqua-Hot domestic water heating system.

1. Completely drain the fresh water storage tank.

2. Disconnect the domestic water demand pump suction line from the fresh water storage tank.

3. Attach an adequate piece of hose onto the suction side of the domestic water demand pump.

4. Place the opposite end of the hose into an adequate supply of non-toxic RV winterization antifreeze (FDA certified as GRAS must be used) and allow the fluid to pump through.

5. Open and close all interior and exterior water faucets one at a time, until ONLY pure RV antifreeze is present. Perform this procedure for both cold and hot water faucets.

6. Remove the hose and reconnect the domestic water demand pump’s suction line to the fresh water storage tank.

De-Winterization

To de-winterize the Aqua-Hot system, completely fill the fresh water storage tank. Open and close the interior and exterior faucets, one at a time, until only clear water is present.

Disinfecting the Domestic Water System

The Aqua-Hot Heating components are not compatible to prolonged exposure to sodium hypochlorite (bleach or liquid bleach.) Using products containing bleach, including water refreshers, may cause corrosion of the domestic water lines, resulting in a catastrophic failure of the Aqua-Hot system by creating leaks that cannot be repaired. This damage is not covered by the Aqua-Hot warranty.

If disinfecting the hot water heating system, be sure to follow NFPA 1192 Standard on Recreational Vehicles “Instructions for Disinfection of Potable Water Systems.”

General Troubleshooting

Should the Aqua-Hot Hydronic Heating System fail to operate, complete the following checks:

1. Verify that the Aqua-Hot is supplied with electrical power.

2. Make sure there is an adequate supply of diesel fuel (at least ¼ tank).

3. Ensure that the Aqua-Hot boiler tank has an adequate supply of antifreeze and water heating solution by checking the level at the boiler tank. If the level is low, reference the maintenance section of this guide for refilling instructions.

4. Verify the functionality of any in-line fuses connected to the Aqua-Hot. Replace these fuses if necessary.

5. Ensure that all RV-side hot water faucets are closed.

6. Visually inspect the interior of the Aqua-Hot to ensure that there are not any pinched or damaged wires.

7. Locate the high-limit thermostat within the Aqua-Hot (see Figure 17). Test the thermostat for functionality, and replace if necessary.

8. Locate and test the ETS module (Figure 17) for functionality. Replace if necessary.

9. Locate and test the fluid circulation pump. Replace if necessary.

10. Locate the three-way valve and test it for functionality. Replace if necessary. 11. Make sure there are no faults displayed on the LCD screen as shown to the right.

Service Log

Measuring Antifreeze Using a Refractometer

Warranty

2-YEAR LIMITED WARRANTY AQUA-HOT® HYDRONIC HEATING SYSTEM

Aqua-Hot Heating Systems Inc. warrants the Aqua-Hot Heater to be free from defects in material and workmanship under normal use and service for a period of two years on both parts and labor commencing upon the original date of registration of the vehicle. Replacement parts are warranted for the remainder of the Heater’s standard warranty coverage or for six months, whichever is greater. The intent of this warranty is to protect the heater’s end-user from such defects, which would occur in the manufacturing of the product. Thus, problems due to improper specifications, improper installations, improper use, the use of accessory parts or parts not authorized by Aqua-Hot Heating Systems Inc., repair by unauthorized persons, and damage or abuse of the heater are specially excluded from warranty coverage.

For additional information, or to obtain a warranty repair authorization, please contact the Aqua-Hot Heating Systems Warranty Administrator at 574-AIR-XCEL (574-247-9235) (7:00 AM to 4:00 PM Mountain Standard Time) or visit www.aquahot.com.

My Comfort Zones are On-Board

Vehicle:

Purchased From:

Dealer Information:

Name:

Location:

Phone Number:

Heating System:

Serial Number: