Airxcel Aqua-Hot AHM-125D Series Service Manual
  1. Manuals
  2. Brands
  3. Airxcel Manuals
  4. Heating System
  5. Aqua-Hot AHM-125D Series
  6. Service manual
Airxcel Aqua-Hot AHM-125D Series Service Manual

Airxcel Aqua-Hot AHM-125D Series Service Manual

Hide thumbs Also See for Aqua-Hot AHM-125D Series:
Table of Contents

Advertisement

Quick Links

Download this manual
Service Manual
100
SERIES
AHM-125-D02
DIESEL

Advertisement

Table of Contents
loading
Need help?

Need help?

Do you have a question about the Aqua-Hot AHM-125D Series and is the answer not in the manual?

Questions and answers

Related Manuals for Airxcel Aqua-Hot AHM-125D Series

Summary of Contents for Airxcel Aqua-Hot AHM-125D Series

  • Page 1 Service Manual SERIES AHM-125-D02 DIESEL...

  • Page 2: Table Of Contents

    Introduction Contents Caution Notes Caution Notes ................2 As you read this information, take particular note of the NOTICE, CAUTION, WARNING, and DANGER symbols when they appear. Introduction ..................3 This information is important for safe and efficient use of the Maintenance Schedule ..............6 Aqua-Hot system.

  • Page 3: Introduction

    System Overview located in the Aqua-Hot. The water is heated by transfer from The Aqua-Hot AHM-125D Series is a Hydronic Heating System the heated antifreeze and distilled water solution. The heated that can provide heat and hot water on demand using a built-in domestic water then flows through the tempering valve to be electric heating element and an external diesel burner.
  • Page 4 Introduction Heat Priority Option: External Diesel Burner: The diesel burner is the Aqua-Hot’s primary and most powerful The Aqua-Hot comes equipped with a three-way valve (some- heat source, and provides all of the heating and hot water times known as the summer/winter valve). This controls the needs when cold temperatures exist, and/or when there is a flow of the antifreeze and water heating solution within the high demand for hot water.
  • Page 5 Introduction Introduction to this Document Welcome to the Aqua-Hot AHM-125D Service Manual. This manual will serve as a guide for diagnosing and repairing the Aqua-Hot, how to perform standard maintenance, and guide If the information in this manual is not followed you through troubleshooting procedures to repair the Aqua-Hot.

  • Page 6: Maintenance Schedule

    Maintenance Schedule Introduction Maintenance Schedule Monthly 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 DO NOT operate the external diesel burner and/or electric note that the coolant level should ONLY be checked when the heating element without antifreeze and water heating Aqua-Hot is completely cold.

  • Page 7: System Features

    System Features Figure 6 System Specifications Electric Element Power Consumption ........1500 W (maximum) Voltage ................110V AC DC Power Power Consumption .......... 57 W (maximum) Zone Heat Circulation Pumps ...................1 Power Consumption (max) ..........20W/1.7A Voltage ................12V DC Interior Heating Maximum Heating Zones .............3 Cozy............6W/0.5A - 8,000 BTU/hr Whisper..........4.5W/0.37A - 4,000 BTU/hr H.E.
  • Page 8 System Features NOTE: This product label is attached to the top of the burner and provides a ready reference to specifications, test standards, and important safety notices. Figure 7 System Specifications TECHNICAL SPECIFICATIONS Heating Medium Ethylene Glycol/Distilled Water Diesel Burner High Power Operation: 5000W Thermal Power (W) Heat Flow ..........

  • Page 9: Component Cut-Aways

    Component Cut-Aways Basic Components Aqua-Hot M125D Heating System 1. Heating Solution Tank 11. Aqua-Hot Controller 2. Plate-to-Plate Heat Exchanger 12. LCD Screen 3. Tempering Valve 13. AC High-Limit Thermostat 4. Three-Way Valve 14. Float Switch 5. Cozy Heat Exchanger 15. AC Activation Relay 6.
  • Page 10 Component Cut-Aways Basic Components Belief Diesel Burner 1. Combustion Air Fan 12. Fuel Pipe 2. Burner Outer Casing 13. Coolant Pump 3. Burner Inner Casing 14. Fuse 4. Combustion Chamber 15. Main Harness Connector 5. Glow Plug 16. Fuel Pump 6.

  • Page 11: Operational Flowchart

    Operational Flowchart Operational Flow Chart A heat source is selected from Interior Control Panel External Diesel Burner Electric Element Electric Heating Element The diesel burner will will activate, providing begin providing heat to the heat to the antifreeze and antifreeze and water heating water heating solution solution present within the within the boiler tank...

  • Page 12: Operating The Aqua-Hot & Lcd

    Operating the LCD Operating the Aqua-Hot & LCD on or off. (Setting specific temperatures can only be done if thermistors are installed. Thermostats would only show ON/OFF.) This document will outline the basic operating instructions for the Aqua-Hot LCD Screen. If the zone temperature is set, but this item is not set to ON, the zone heat exchanger will Climate Pages:...
  • Page 13 Operating the LCD Electrical Element Activation Similar to the external diesel burner, tapping the electric item will signal to the controller to activate the AC electric relay, energizing the 1500W electric element within the Aqua-Hot. The electric element also has two modes: ON and OFF. While set to ON, the electric element will work to maintain a tank temperature of 180°...

  • Page 14: Aqua-Hot Controller

    Controller The Aqua-Hot Controller System Voltage: System voltage faults indicate that there is a problem with the RV-side power supply which The Aqua-Hot AHM-125D operates on a controller platform powers the Aqua-Hot. which has been modernized and updated from the previously The Aqua-Hot can only operate within a used Electronic Controllers and Relay Control Boards of older voltage range of 11V DC to 16V DC.
  • Page 15 Controller The fault codes shown above will cover the most common FAULT indicates that there is an issue with the Aqua-Hot related issues. For more complex issues, it may be burner. necessary to utilize the DIAG screens, which will be explained Electric: next.
  • Page 16 Controller Burner Status: The Burner Status element on this page indicates the status of the external diesel burner. LTCO Status: The LTCO status indicates the sensor reading from the Low-Temperature Cutoff Thermostat, which is the device that governs whether to provide heat or hot water.
  • Page 17 Controller Testing Functionality: One of the new features of this control system is the ability to independently activate specific elements within the Aqua-Hot for testing purposes. Figure 23 Electric Activating the Electric heating sub-system will energize the relay which controls the AC electric element. Figure 21 After tapping this button on the screen, there should be an audible click from within the Aqua-Hot boiler tank.

  • Page 18: Controller Replacement Procedure

    Controller Controller Replacement Procedure: 5. Install the replacement controller using the 4 screws previously removed. 1. If possible, tap the three lines icon at the bottom right corner of the LCD screen. 6. Carefully reinstall all of the plugs from the DC harness. •...
  • Page 19 Controller Instructions for Controller Setup after Installation: After replacement and installation of the controller, the system will need to be updated via the LCD Screen or RV Control panel. 1. Provide power to the main harness of the Aqua-Hot. After the screen lights up, tap the three lines icon on the bottom right corner.

  • Page 20: Float Switch

    Fluid Level Sensor Float Switch Float Switch Troubleshooting Procedure: Locate the float switch The float switch monitors the fluid level within the Aqua-Hot. This device is intended as a fail-safe measure which will disengage (Figure 30) the Aqua-Hot if the fluid ever drops below a set threshold. The float switch is located on the boiler tank face behind the AC cover.
  • Page 21 Fluid Level Sensor Float Switch Before continuing to the replacement procedure, ensure that the unit has cooled to ambient temperature, all power sources have been disconnected, and the unit is completely shut off. AC Cover Replacement Procedure: In order to replace the float switch, a float switch kit with the switch and the quick disconnect terminal must be ordered.

  • Page 22: High-Limit Thermostat

    High-Limit Thermostats High-Limit Thermostat Troubleshooting Procedure: The Aqua-Hot is equipped with a resettable High-Limit Thermostat. This thermostat is in place to prevent the heater Disconnect AC power to from operating beyond its safe operational threshold. This the Aqua-Hot system. thermostat is resettable and easily replaceable. AC Cover Locate the high-limit thermostat...
  • Page 23 High-Limit Thermostats Replacement Procedure: AC Cover If it has been determined that the high-limit thermostat needs to be replaced, it can be easily replaced by following the directions below. 1. Disconnect all sources of AC and DC power from the Aqua- Hot (the AC access cover will need to be removed - see Figure 36).

  • Page 24: Low-Temperature Cutoff Thermostat

    Low-Temp Cutoff Thermostat Low-Temperature Cutoff Thermostat Locate the Aqua-Hot LCD screen. Navigate to INPUTS FROM AQUA-HOT. Turn on a hot water faucet within the RV. Wait 1 minute for the sensor to cool down. Monitor the Aqua-Hot LCD. Does the LTCO element display “HOT WATER”? Figure 38 The Low-Temperature Cutoff Thermostat (LTCO) is installed to measure the incoming domestic water temperature.

  • Page 25: Three-Way Valve

    Three-Way Valve Three-Way Valve Continue trouble- Continue trouble- shooting here shooting here The three-way valve (aka the summer/winter valve) is responsible for changing the flow of coolant either through the interior heating zone (int heat) or circulating coolant within the Grab the hoses shown in boiler tank (hot water mode) to prioritize hot water.

  • Page 26: Plate-To-Plate Heat Exchanger

    Three-Way Valve Plate-to-Plate Heat Exchanger Before replacing the 3-way valve, you must purchase the repair kit. The Repair Kit should include: • Three-Way Valve Introduction: • Black Nylon elbow adapter The only issue the plate-to-plate heat exchanger may have is •...

  • Page 27: Tempering Valve

    Tempering Valve Tempering Valve Testing Procedure: Follow the testing procedure to the right in order to diagnose Introduction: the tempering valve. Troubleshoot the tempering valve if the The tempering valve of the Aqua-Hot mixes the hot domestic following conditions have occurred: water from the Aqua-Hot with cold incoming domestic water to •...
  • Page 28 Tempering Valve Replacement Procedure: Remove all fittings from the tempering valve as shown below. 1. Shut off the external domestic water connection, and open a hot water faucet valve within the RV to relieve the water pressure. 2. Open the RV domestic water drain valve and release water from the system.

  • Page 29: Tank Fluid Circulation Pump

    Fluid Circulation Pump Tank Fluid Circulation Pump Power cycle the Aqua-Hot to clear any current faults. Introduction: The fluid circulation pump operates to provide fluid circulation Locate the Aqua-Hot LCD to either the interior heating zone or the antifreeze boiler tank screen.
  • Page 30 Fluid Circulation Pump Replacement Procedure: 1. Place a paper towel on the bottom of the cabinet. (This is to help absorb any residual coolant left in the lines upon pump removal.) 2. Drain coolant from the lower tank fitting (see Figure 53). Pour into a bucket to be reused later.

  • Page 31: Ac Electric System

    Fluid Circulation Pump AC Electric System AC Electric System Locate the Aqua-Hot LCD screen. Navigate to the TESTING page, then Introduction: tap ELECTRIC (Figure 55) The AC Electric system of the Aqua-Hot AHM-125D unit functions to provide heat to the Aqua-Hot boiler tank. This is done with an electric element and an electric relay.
  • Page 32 Fluid Circulation Pump AC Electric System Replacement Procedure: 1. Ensure that the Aqua-Hot has been completely shut down and all power sources have been disconnected. Be sure the boiler tank is completely cooled. Failure to disconnect all power supplies and/or allow 2.

  • Page 33: Ac Relay

    Fluid Circulation Pump AC Relay AC Relay Replacement Procedure: 1. Ensure that the Aqua-Hot has been completely shut down Introduction: and all power sources have been disconnected. Be sure the boiler tank is completely cooled. The AC Relay is an electrical device where the DC circuit from 2.

  • Page 34: Ets Module

    ETS Module ETS Module Using a meat thermometer, measure the temperature of the tank face. Record Introduction: this temperature on a piece of paper. The ETS (Engine Temperature Sensor) Module is a brass thermistor that continually measures the temperature of the fluid within the Aqua-Hot boiler tank.
  • Page 35 ETS Module Replacement Procedure: 11. Once this has been completed, locate the Aqua-Hot LCD screen, navigate to the test section, and run the fluid If the ETS Module has been diagnosed and a replacement must circulation pump (and if applicable the boost pump) for at be made, follow the instructions below.

  • Page 36: Fuel System Replacement

    ETS Module Fuel System Replacement NOTE: The diagram above is not drawn to scale. It is simply Figure 65 a reference for proper installation of the fuel system for the Belief Diesel Burner. Fuel System Plumbing • It is recommended to replace the filter once a year or after extended period of non-use.
  • Page 37 ETS Module Fuel System Replacement CORRECT CORRECT WRONG Bubble WRONG Bubble NOTE: The fuel lines must be secured and supported properly to avoid air Fuel Line to Coupler Hose traps or bubbles. Avoid unnecessary dips or bends, the line should not run A Clamp B Coupler C Fuel Hose...

  • Page 38: Fuel System Purge Procedure

    Fuel System Purge ETS Module Fuel System Fill Procedure Perform this procedure after any fuel components have been serviced and/or replaced. • Ensure all fuel system connections have been made. 4. Repeat steps 1-3 until fuel reaches the burner. A rumble from the burner will be heard and the exhaust temperature •...

  • Page 39: Burner Troubleshooting

    Burner Troubleshooting ETS Module External Diesel Burner Troubleshooting The troubleshooting procedures listed below are arranged in order of repair complexity. Do not replace parts without correctly determining the failure. Follow the directions below in order to troubleshoot the diesel burner. Do not skip through the troubleshooting steps, as this may needlessly complicate unit diagnosis and repair.
  • Page 40 Burner Troubleshooting ETS Module External Diesel Burner Faults & Remedies Fault Fault Fault Cause Remedy Fault Cause Remedy Code Code Burner: Voltage too high • Wait for flame sensor • Check power supply (exceeds 16V) cooling Burner: Failed to Ignite •...
  • Page 41 Burner Troubleshooting ETS Module General Failure Symptoms of the Burner This section will cover the typical failures of the diesel burner. Refer to the table more fails and their remedies. Failure Symptom Possible Cause Remedy No combustion after start or automatic Switch off burner and switch back on.

  • Page 42: Burner Operation After Service

    Burner Operation ETS Module Burner Operation after Service The first operation of the burner (after service or maintenance) with the Aqua-Hot may not light up perfectly. It may take 5-6 starts for the burner to ignite for the first start-up after service, because the fuel pump needs to fill the fuel lines leading to the Failure to follow instructions on the fuel delivery system can cause damage to the Aqua-Hot AHM-125D, the diesel burner,...

  • Page 43: General Troubleshooting

    General Troubleshooting Lack of Interior Heat or Hot Water Fluid Fill Port A lack of interior heat or hot water when provided with adequate High-Limit heat from either the electric element and/or the diesel burner Thermostat can be attributed to an overheat thermostat, the Aqua-Hot controller, the three-way valve, or the fluid circulation pump.

  • Page 44: Winterization

    Winterizing the Aqua-Hot General Troubleshooting 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 Not winterizing the Aqua-Hot when freezing temperatures domestic water heating system.

  • Page 45: Appendix A: System Schematics

    System Schematics NOTE: All connectors are shown from Pin insertion side. ©Aqua-Hot® AHM-125-D02 Service Manual REV 221202 p. 45...
  • Page 46 System Schematics AHM-125-D02 Service Manual REV 221202 p. 46 ©Aqua-Hot®...
  • Page 47 System Schematics ©Aqua-Hot® AHM-125-D02 Service Manual REV 221202 p. 47...
  • Page 48 System Schematics AHM-125-D02 Service Manual REV 221202 p. 48 ©Aqua-Hot®...

  • Page 49: Appendix B: Parts

    System Schematics Parts NOTE: For more parts & information, please reference the AHM- 125-D02 Parts manual found online at aquahot.com/library.aspx. ELE-014-712 ELX-THM-309 Thermistor, Tank Temperature Sensor Thermistor, 10K NTC, Room Temperature Sensor ELE-LCD-050 ELE-100-111 RV-Side Wire Harness (optional) Aqua-Hot LCD Screen, RVC 3.5in ELE-RVC-100 ELE-DIV-100 RVC Display Cable...
  • Page 50 System Schematics Parts ELE-HLT-125 ELE-LTC-135 VAC High Limit Thermostat 215°F w/ Leads Low-Temperature Cutoff Thermostat w/ Spade Terminals ELE-100-M01 ELX-2E7-102 1500W, 120 VAC Electric Element, 1” NPSM Controller, 12VDC, 100-200 Series, Kit ELX-135-M01 EXE-103-0EX Heat Exchanger, Cozy III Float Switch Kit, ½” NPT w/ Quick Disconnect Terminal AHM-125-D02 Service Manual REV 221202 p.
  • Page 51 System Schematics Parts PLX-102-050 PLX-100-900 Fluid Circulation Pump Small Heat Exchanger, (2) ½” FNPT, (2) 2” MNPT PLX-111-125 ELE-400-900 Pressure Relief Valve, 125 PSI Harness, Buehler C20 Pump PLX-362-100 PLX-251-M01 Tempering Valve Kit, Three-Way Motorized Valve, ½” NPT ©Aqua-Hot® AHM-125-D02 Service Manual REV 221202 p.
  • Page 52 System Schematics Parts ELX-232-948 SME-135-002 AC Relay, 30A 277VAC Cover, AC Element Cover for 125 Series ¾” PLX-000-433 GBX-125-117 Assembled Fuel Pump Hose, ¾” Safety Stripe, Rubber MSX-907-162 GBX-125-103 Refractometer Belief 5kW Diesel Burner Circulation Pump AHM-125-D02 Service Manual REV 221202 p.
  • Page 53 System Schematics Parts GBX-125-121 GBX-125-122 Fuel Hose to Burner Fuel Hose to Fuel Tank (blue) (clear) (Couplers & check valve included) HDX-102-111 HDX-102-113 Clamp, (10.5mm), Soft Hose and Tube Clamp, ⅜ to (11.3mm), Soft Hose and Tube GBX-125-102 GBX-125-112 Burner K_Line Converter Burner Wiring Harness ©Aqua-Hot®...

  • Page 54: Appendix C: Measuring Antifreeze

    Appendix Measuring Antifreeze Using a Refractometer Measuring Antifreeze Using a Refractometer Calibration Screw Prism Assembly Daylight Plate Assembly Eye Piece Properly Apply Antifreeze to the Prism Assembly Use the guide below to properly apply the ethylene glycol mix- ture to the prism assembly of the refractometer. Once that is complete, peer through the eyeglass of the refractometer to continue to the next step.
  • Page 55 Service Manual SERIES AHM-125-D02 DIESEL Aqua-Hot Heating Systems, LLC 7501 Miller Drive, Frederick, CO 80504 Visit us online at www.aquahot.com Call us at 574-AIR-XCEL (574-247-9235). ©2022 Aqua-Hot Heating Systems, LLC. Printed in the USA...

Table of Contents