Airxcel Aqua-Hot 200 Series Service Manual
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Airxcel Aqua-Hot 200 Series Service Manual

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Service Manual
200
Series
AHE-250-D03

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Summary of Contents for Airxcel Aqua-Hot 200 Series

  • Page 1 Service Manual Series AHE-250-D03...

  • Page 2: Table Of Contents

    Introduction Contents Caution Notes As you read this information, take particular note of the NOTICE, Caution Notes ................2 CAUTION, WARNING, and DANGER symbols when they appear. Introduction ..................3 This information is important for safe and efficient use of the Maintenance Schedule ..............5 Aqua-Hot system.

  • Page 3: Introduction

    Introduction System Overview Introduction to this Document The Aqua-Hot 200 Diesel Series is a Hydronic (water- Welcome to the Aqua-Hot 250-D03 Service Manual. This based) Heating Systems that can provide heat and tank-less, manual will serve as a guide for diagnosing and repairing the continuous hot water in one small, easy to install package.
  • Page 4 Introduction Read all instructions before servicing 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 manual before servicing or using the Aqua-Hot System to reduce the risk of injury to persons or damage to the equipment.

  • Page 5: Maintenance Schedule

    Maintenance Schedule Introduction Maintenance Schedule Monthly Maintenance Check the Aqua-Hot’s antifreeze and distilled water heating solution to ensure that it is at the proper level. This can be DO NOT operate the diesel burner and/or electric heating accomplished by visually checking the coolant level in the Aqua- element without antifreeze and distilled water heating Hot’s expansion bottle;...

  • Page 6: System Features

    System Features Figure 2 System Specifications Electric Element Power Consumption ........1000 W (maximum) Voltage ................120V AC DC Power Heat Input ..........56,000 BTU/hr ± 10% Fuel Consumption ..........0.40 gallon/hr Power Consumption ......... 108W (maximum) Zone Heat Circulation Pumps ...................1 Power Consumption (max) ............. 21W Voltage ................

  • Page 7: Component Cut-Away

    Component Cut-Away System Features 250-D03 1. Access Cover Screw 11. 120V AC Connection 2. Drain Valve 12. Diesel Fuel Return Port 3. Zone Circulation Pump 13. Diesel Fuel Supply Port 4. 3-Way Valve 14. Expansion Tank Connection 5. Diesel Burner Controller 15.

  • Page 8: Operational Flowchart

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

  • Page 9: Operating The Aqua-Hot

    Operating the Aqua-Hot 250-D01 Switch Panel Controller Operating the Aqua-Hot Section A: This section shows the current zone temperature (shown as 71°F in the example Introduction: above) as well as a button to turn the zone This document will outline the basic operating instructions on or off.
  • Page 10 Operating the Aqua-Hot Controller 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.

  • Page 11: 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 Introduction: powers the Aqua-Hot. The Aqua-Hot can only operate within a The Aqua-Hot 250-D03 operates on a controller platform voltage range of 11V DC to 16V DC.
  • Page 12 Controller necessary to utilize the DIAG screens, which will be explained Electric: next. The Electric section indicates the controller’s current handling status of the AC electric relay. This status indicates that the controller is attempting to activate the element relay only. This does NOT indicate whether the electric element is in working order or not.
  • Page 13 Controller Burner Status: The Burner Status element on this page indicates the status of the 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. LLCO Status: LLCO status relays the current sensor reading of the Low-Level Cutoff sensor within the...
  • Page 14 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 12 Electric (C): Activating the Electric heating sub-system will energize the relay which controls the AC electric element. Figure 10 After tapping this button on the screen, there should be an audible click from within the Aqua-Hot cabinet.
  • Page 15 Controller Controller Replacement Procedure: 4. Using a ⅜” (10mm) socket, remove the 3 hex nuts from the top, left side, and bottom of the mounting plate (SAVE 1. If possible, tap the three lines icon at the bottom right THE NUTS TO USE AGAIN) corner of the LCD screen.
  • Page 16 Controller Slide the controller and mounting plate outwards and out 12. Once the controller and mounting plate are properly of the unit. seated on the mounting studs, fasten the mounting • The mounting plate has three key-ways holding it in plate to the wall of the Aqua-Hot using the previously place (no nuts or other fasteners).
  • Page 17 Controller Instructions for Controller Setup after Installation: 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. Tap the AQUA-HOT DIAGNOSTICS icon. Then tap and hold (for 3 seconds) within the Aqua-Hot Information section. Tap SERIAL NUMBER and follow the prompts on the screen.

  • Page 18: Exhaust System

    Exhaust System Controller Exhaust System Requirements • The exhaust must be able to freely exit away from the Introduction: vehicle without any obstructions. The Aqua-Hot’s exhaust is hot and must be kept away from any • Use standard two-inch automotive-type exhaust piping heat-sensitive material.

  • Page 19: Interlock Switch

    Interlock Switch Controller Components Introduction: This section of the Service Manual details various Failure to disconnect all power supplies and/or allow the components of the Aqua-Hot that may require troubleshooting unit to cool before servicing could cause serious damage or and/or replacement in the event of malfunction.

  • Page 20: Fluid Level Sensor

    Fluid Level Sensor Fluid Level Sensor • Ensure that AC electrical power is supplied to the Aqua- Hot’s electric element. Introduction: • Ensure that the fluid level sensor is oriented correctly (see below). The fluid level sensor monitors the current fluid level within the Aqua-Hot.
  • Page 21 Fluid Level Sensor 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� Fluid Return Port Replacement Procedure: In order to replace the fluid level sensor, the overflow bottle must also be replaced.

  • Page 22: Ets Module

    Fluid Level Sensor ETS Module ETS Module 5. If the temperatures do not match, disconnect the ETS module from its leads on the wire harness. The ETS (Engine Temperature Sensor) Module is a brass 6. Navigate back to the INPUTS FROM AQUA-HOT section thermistor that continually measures the temperature of the of the LCD/RV display screen.
  • Page 23 Control Thermostat Fluid Level Sensor Replacement Procedure 9. Reconnect wire J4-5 and wire J4-6 to the new ETS module. 1. Ensure that the Aqua-Hot has been completely shut 10. Refill the Aqua-Hot’s boiler tank with the previously down, all power sources disconnected, and the unit has drained antifreeze and water heating solution using an been allowed to cool completely.

  • Page 24: Ac High-Limit Thermostat

    High-Limit Thermostats AC High-Limit Thermostat 2. Ensure that the unit has been shut down and completely cooled before continuing. Introduction: 3. Shut off the RV-side power breaker to the Aqua-Hot. 4. Disconnect the 3-pin AC Molex plug. Leave the DC power The AC high-limit thermostat serves as a safety measure supply connected.
  • Page 25 High-Limit Thermostats Replacement Procedure: provided and reinstall the mixing valve assembly. 11. Make sure the replacement AC high-limit thermostat is If it has been determined that the AC high-limit thermostat functioning properly by testing for continuity across this needs to be replaced, it can be easily replaced by following the thermostat.

  • Page 26: Burner High-Limit Thermostats

    High-Limit Thermostats Burner High-Limit Thermostats Troubleshooting Procedure: 1. Locate the high-limit thermostats (see Figure 41). Introduction: 2. Disconnect the burner thermostats using the information below: The burner high-limit thermostats serve as a safety measure in the event that the burner continues to operate after the •...

  • Page 27: Low-Temperature Cutoff Thermostat

    Low-Temp Cutoff Thermostat Low-Temperature Cutoff Thermostat 3. If the ‘Low-Temperature Cutoff Status” display shows HOT WATER when no hot water is running, complete the following: Introduction: • Disconnect wire J4-1 and J4-2 from the low- The Low-Temperature Cutoff Thermostat (LTCO) operates temperature cutoff thermostat.
  • Page 28 Low-Temp Cutoff Thermostat Replacing the Low-Temperature Cutoff Thermostat: 1. Ensure that the Aqua-Hot has been completely shut down and that all the power sources have been disconnected. 2. Locate the Low-Temperature Cutoff Thermostat on the Failure to disconnect all power supplies and/or allow Aqua-Hot.

  • Page 29: Three-Way Valve

    Three-Way Valve Three-Way Valve Introduction: The Aqua-Hot has a three-way directional valve to control coolant priority within the unit. This ensures that there will be a supply when heated water is being called for, but can provide interior heating when the need arises. Figure 46 •...
  • Page 30 Three-Way Valve Replacement Procedure: 1. Ensure that the Aqua-Hot has been completely shut down, all power sources have been disconnected, and the unit has completely cooled. Failure to disconnect all power supplies and/or allow 2. Use clamp hose pliers to pinch tubing surrounding the the unit to cool before servicing could cause serious three-way valve as indicated in Figure 48.

  • Page 31: Tempering Valve

    Tempering Valve Tempering Valve Introduction: The tempering valve of the Aqua-Hot mixes the heated Failure to disconnect all power supplies and/or allow domestic water from the boiler tank with cold incoming the unit to cool before servicing could cause serious domestic water at a preset ratio to deliver steady hot water damage or personal injury.

  • Page 32: Fluid Circulation And Stir Pump

    Fluid Circulation Pump Circulation and Stir Pump 4. If the circulation pump does not activate, navigate to the TEST screen and activate the internal circulation pump. Introduction: 5. Using a multimeter, test for voltage between pins J6-7 and J6-8. The fluid circulation pump operates to provide fluid •...
  • Page 33 Fluid Circulation Pump Replacement Procedure: Ensure that the Aqua-Hot has been completely shut down, all power sources have been disconnected, and that the unit has been allowed to cool completely. Failure to disconnect all power supplies and/or allow 2. Clamp the zone outlet, and the zone return with hose pinch- the unit to cool before servicing could cause serious pliers as shown below.

  • Page 34: Ac Electric System

    1. Turn OFF both the electric and the burner on the LCD Introduction: screen. The AC Electric system of the Aqua-Hot 200 Series unit functions 2. Allow the unit to cool completely. to provide supplementary heat to the Aqua-Hot boiler tank.
  • Page 35 Fluid Circulation Pump AC Electric System • Using an ohmmeter, check for continuity across wires J6-1 and J6-2 of the AC relay. If no continuity exists at this point, the relay must be replaced. 4. Verify that the electric element has the proper resistance: Failure to disconnect all power supplies and/or allow •...

  • Page 36: Ac Relay

    Fluid Circulation Pump AC Electric System AC Relay Introduction: The AC relay is an electrical device where the DC circuit from the 10. Using the wiring diagram on Page 100, connect the wires controller determines whether the AC power is permitted to flow previously removed to the replacement relay.

  • Page 37: Diesel Burner

    Fluid Circulation Pump Diesel Burner Diesel Burner Overview Standard automotive diesel fuel is to be used as the fuel source. The diesel burner serves as the primary heating source for the Key components are called out below. The diesel burner has an Aqua-Hot 250-D03.
  • Page 38 Fluid Circulation Pump Diesel Burner 250-D03 Diesel Series Service Manual REV 220302 p. 38 ©Aqua-Hot®...
  • Page 39 Fluid Circulation Pump Diesel Burner Torque Specs Part Number Description WPE-300-901 Controller, 12V DC Item Torque Value WPX-362-107 Controller Mounting Bracket 2 Nm WPX-470-562 Coil Mounting Screw 1.0 +0.5 Nm WPX-101-838 Ignition Coil, 12V DC 2 Nm (18 lb-in) WPX-404-918 Ignition Wire Boot 5 - 6 Nm(44 -53 lb-in) WPX-178-624...
  • Page 40 Fluid Circulation Pump Diesel Burner Torque Specs Part Number Description WPX-434-795 C-Plug Harness Item Torque Value WPX-148-210 Blower Casing Screw 5.5 - 6.5 Nm (48.5-57.5 lb-in) WPX-152-552 Washer, Lock, Blower Casing 41 (Fan .457mm + .05mm ( STANDARD SHIM WPX-301-841 Blower Housing Gap) ) - 0.0mm...
  • Page 41 Fluid Circulation Pump Diesel Burner Torque Specs Part Number Description WPX-322-083 Valve, Fuel Solenoid 12V DC Item Torque Value WPX-386-650 Valve, Fuel Solenoid Kit 50 (nut) 2 Nm WPX-267-279 Electrode Bolt 11.5 Nm (8.5 lb-ft) (fuel fitting to fuel tower) WPX-152-560 Washer, Lock, Electrode WPX-278-971...
  • Page 42 Fluid Circulation Pump Diesel Burner Torque Specs Part Number Description WPX-150-754 Banjo Bolt Item Torque Value WPX-151-157 Copper Gasket Ring 15 ± 1.5 Nm WPX-661-002 Banjo Fuel Pipe - Supply, DBW 2010 (with Straight Tube) 3 Nm WPX-661-001 Banjo Fuel Pipe - Return, DBW 2010 (with Straight Tube) 20 Nm WPX-277-282...

  • Page 43: Diesel Burner Operation

    Diesel Burner Operation Fluid Circulation Pump Diesel Burner Operational Flow Chart The Motor will continue to run for approximately 3 Once the ignited air-fuel additional minutes. This mixture (FLAME) is process is referred to as observed by the Flame the Purge Cycle, which Sensor, the Ignition coil cools the heater’s internal will automatically switch...
  • Page 44 Diesel Burner Operation Fluid Circulation Pump NOTE: The Motor and Combustion Air Blower will begin to operate only if the ETS Module is calling for heat. 250-D03 Diesel Series Service Manual REV 220302 p. 44 ©Aqua-Hot®...
  • Page 45 Diesel Burner Operation Fluid Circulation Pump ©Aqua-Hot® 250-D03 Diesel Series Service Manual REV 220302 p. 45...
  • Page 46 Diesel Burner Operation Fluid Circulation Pump The Diesel-Burner will continue to produce heat in this manner until it is switched off either manually or by the ETS Module , which occurs when the coolant temperature in the Aqua-Hot’s Boiler Tank reaches 190°F (±5).

  • Page 47: Detaching The Diesel Burner

    Fluid Circulation Pump Detaching the Burner Instructions for Detaching the Diesel Burner Be sure to move the diesel burner on the interior control Be sure to clamp off the Fuel Supply and Return panel to the OFF position and disconnect the diesel burner’s lines at the ports on top of the Aqua-Hot prior to power supply before detaching the diesel burner from the beginning this replacement procedure�...
  • Page 48 Fluid Circulation Pump Detaching the Burner Step 3: Disconnect the Diesel Burner’s Controller Locate the controller and disconnect both plugs. Diesel Burner Controller Figure 68 Diesel Burner Controller Figure 67 Step 4: Remove the fuel lines from the Aqua-Hot 1. Locate where the fuel lines on the diesel burner connect to 2.
  • Page 49 Fluid Circulation Pump Detaching the Burner Step 5: Remove the Diesel Burner from the Aqua-Hot The diesel burner is secured to the Aqua-Hot with two nuts that can be loosened, and swung out of the way by using a 10mm socket wrench with a 10”...

  • Page 50: Reattaching The Diesel Burner

    Reattaching the Burner Fluid Circulation Pump Reattaching the Diesel Burner to the Aqua-Hot When reattaching the diesel burner, be sure to properly align the diesel burner before tightening the eye-bolt nuts� Visually inspect all the rubber grommets on the top and bottom of the burner’s cast- aluminum blower casing to ensure they are in place�...
  • Page 51 Reattaching the Burner Fluid Circulation Pump Step 2: Reattach the fuel lines to the Aqua-Hot Align the fuel lines on the diesel burner with the fittings on the Aqua-Hot, and using a ” wrench, tighten down both the supply and return fuel fittings. Diesel Fuel Return Diesel Fuel Supply NOTE: Be sure to note the fuel line ports.
  • Page 52 Reattaching the Burner Fluid Circulation Pump Step 4: Reinstall the Access Cover Reinstall the Aqua-Hot’s access cover and securely tighten the three bolts securing the access cover in place. Figure 81 NOTE: The access cover must be installed prior to operation as a safety switch (interlock) exists.

  • Page 53: Diesel Burner Components

    In order to perform the following procedures, it may necessary to detach the diesel burner head. NOTE: The Aqua-Hot 200 Series is equipped with a 20A Fast Blow Fuse, located on the J2-12 wire, between the Aqua-Hot main plug and diesel burner controller’s B-plug.
  • Page 54 Fluid Circulation Pump Burner Components RPM Test: 1. Disconnect the ignition cables from the ignition electrodes. Diesel Burner Ignition Coil 2. Remove the four ignition coil screws that secure the ignition Ignition Coil Cables coil to the protection cap. 3. Lift the ignition coil and disconnect its wires from the C-plug harness prior to removing completely.
  • Page 55 Fluid Circulation Pump Burner Components Motor Replacement Procedure: 1. Follow the directions on Page 47 for detaching the diesel burner. 2. Remove the four ignition coil screws that secure the ignition coil to the protection cap. Lift the ignition coil to disconnect Be sure to turn the Diesel Burner on the LCD display its wires from the C-plug harness prior to removing.
  • Page 56 Fluid Circulation Pump Burner Components Electrode Adjustment Gauge Protection Housing Blower Housing Blower Casing Motor Flange Figure 92 250-D03 Diesel Series Service Manual REV 220302 p. 56 ©Aqua-Hot®...

  • Page 57: Flame Sensor

    Fluid Circulation Pump Burner Components Flame Sensor 3. Connect the flame sensor’s green and blue wires to an ohmmeter. The flame sensor is a photo resistive device which supplies the 4. Check resistance by placing a shop rag over the flame diesel burner’s controller with a DC voltage signal when it sensor’s glass surface, to simulate a no-flame condition.
  • Page 58 Fluid Circulation Pump Burner Components Flame Sensor Replacement: Connect the flame sensor’s green wire to the green C-plug 1. In order to perform the following procedures, it is necessary harness wire (pin 6), and connect the blue wire to the to detach the diesel burner head.

  • Page 59: Ignition Electrodes

    Fluid Circulation Pump Burner Components Ignition Electrodes Ignition Electrode Adjustment Procedure: 1. Follow the directions for detaching/reattaching the diesel The diesel burner’s ignition coil produces a high voltage ignition burner on Page 47. spark (approximately 8000 volts) across the ignition electrodes, 2.
  • Page 60 Fluid Circulation Pump Burner Components Replacement Procedure: Install retaining clamp and retaining clamp bolt and finger 1. Using a 10mm socket, loosen and remove the retaining tighten. clamp bolt and the retaining clamp. 8. Follow the ignition electrode adjustment procedure to 2.

  • Page 61: Ignition Coil

    Fluid Circulation Pump Burner Components Ignition Coil The diesel burner’s ignition coil produces a high voltage ignition spark (approximately 8000 volts), which is released across the metal tips on the ignition electrodes during the initial diesel Before replacing the ignition coil, verify the electrodes are not burner start up.

  • Page 62: Fuel Nozzle

    Fluid Circulation Pump Burner Components Fuel Nozzle 3. Remove both the ignition cables from the ignition electrodes, or connect a jumper wire (with alligator clips) across the metal tips of the electrodes. The fuel nozzle is simply a fuel atomizer. It reduces the diesel fuel into a fine spray which is mixed with incoming combustion 4.
  • Page 63 Fluid Circulation Pump Burner Components NOTE: Be sure to use care when handling the new fuel nozzle. Oils and/or small dust or dirt particles from your hands may plug the nozzle’s small orifice. A partially plugged orifice will restrict fuel flow, which will affect the combustion Be sure to reattach the diesel burner head prior to process of the diesel burner.

  • Page 64: Fuel Solenoid

    Fluid Circulation Pump Burner Components Fuel Solenoid Fuel Solenoid Replacement Procedure: 1. Disconnect the C-plug harness’ violet (+) and brown (-) The fuel solenoid allows the flow of diesel fuel to the diesel wires from the fuel solenoid. burner’s fuel nozzle. 2.

  • Page 65: Fuel Pump

    Fluid Circulation Pump Burner Components Fuel Pump 6. If fuel does not flow out of the return line into the empty container, the fuel pump must be replaced, The fuel pump draws diesel fuel from the vehicle’s fuel tank If fuel does flow through the fuel pump when ran off an and creates a preset pressure of 145 PSI, which is required external source, inspect the following in the RV: for proper fuel atomization.
  • Page 66 Fluid Circulation Pump Burner Components nozzle stand and the ignition electrodes. 3. Loosen the supply and return banjo bolts to remove the fuel supply and return pipes from the fuel pump. Disconnect the high pressure fuel pipe from both the fuel pump and the Inspect the nylon drive gear’s cavity inside the cast- nozzle stand.
  • Page 67 Fluid Circulation Pump Burner Components Figure 109 Description Grommet, Blower Casing, Left Grommet, Blower Casing, Right Flame Sensor Retaining Clip, Photo Disc Photo Disc Fuel Pump High Pressure Fuel Tube Banjo Bolt Gasket Ring, Copper Banjo Fuel Tube, Supply Banjo Fuel Tube, Return Mounting Screw, Fuel Pump Washer, Lock, Fuel Pump Fuel Nozzle, 0.35 GPH...

  • Page 68: Bearings

    Fluid Circulation Pump Burner Components Bearings Disconnect the motor’s black (+) and brown (-) wires from the C-plug harness’ wires. The bearings support the combustion air blower’s shaft and 6. Remove the four blower housing screws that secure the allows the blower to turn smoothly. blower housing to the blower casing.
  • Page 69 Fluid Circulation Pump Burner Components 4. Remove the four ignition coil screws that secure the NOTE: Be sure to inspect the blower casing’s bore/bearing ignition coil to the protection cap. Lift the ignition coil and cavity for signs of damage due to potentially seized bearings. disconnect its black (+) and brown (-) wires from the C-plug If damage is present, the blower casing must be replaced.
  • Page 70 Fluid Circulation Pump Burner Components 16. Reinstall the protection cap. Reconnect the black (+) and brown (-) wires of the ignition coil to the C-plug harness’ yellow (+) and brown (-) wires. Reinstall the ignition coil and secure to the protection cap with the four ignition coil screws.

  • Page 71: Diesel Burner Controller

    Fluid Circulation Pump Burner Components Condition 1: Diesel Burner Controller A battery voltage level between 11.6-14 Volts DC must be present at the diesel burner controller during all testing. It may be necessary to perform a voltage check to ensure that this condition exists.
  • Page 72 Fluid Circulation Pump Burner Components Ignition Coil Circuit Test: diesel-burner controller must be replaced. If voltage is present, proceed to the next circuit test. Turn the diesel burner OFF and locate the diesel-burner controller’s C-plug. Also, locate the VDC high-limit DC High-Limit Thermostat Circuit Test: thermostat and disconnect it’s 2-way male plug from the (white plastic) 6-way female connector.

  • Page 73: Checking Fuel Pressure

    Fluid Circulation Pump Fuel Pressure Instructions for Checking Fuel Pressure: NOTE: A fuel pressure gauge is used to properly check the fuel pump’s pressure setting. The fuel pump is preset to 145 PSI. Perform the following procedure to check for a proper fuel pressure setting. Step 1: Remove the diesel burner Refer to the section on detaching the diesel burner on page 47.
  • Page 74 Fluid Circulation Pump Fuel Pressure Step 3: Install the fuel pressure gauge 1. Using a ⅝” and ¾” wrench, remove the fuel nozzle. Figure 121 2. Using a ⅝” and ¾” wrench, install the fuel pressure gauge. Figure 122 250-D03 Diesel Series Service Manual REV 220302 p.
  • Page 75 Fluid Circulation Pump Fuel Pressure Step 4: Running burner off an external fuel source 1. Using an external fuel source and rubber fuel lines, hook the burner supply and return fuel lines up to run off the external fuel source. Figure 123 A spark will appear across the ignition electrodes for a brief moment after the diesel burner has been activated�...

  • Page 76: Adjusting Fuel Pressure

    Fluid Circulation Pump Fuel Pressure Instructions for Adjusting Fuel Pressure: Step 1: Follow the directions for Adjusting the Fuel Pressure 1. Using an external fuel source and rubber fuel lines, hook the burner supply and return fuel lines up to run off the external fuel source.
  • Page 77 Fluid Circulation Pump Fuel Pressure Step 2: Adjust the Fuel Pressure to 145 PSI 1. Once the fuel solenoid has been activated, and the fuel pressure gauge is registering a pressure, the fuel pressure can be adjusted. To increase the fuel pressure turn the pressure adjustment screw clockwise, and to reduce the fuel pressure, turn the pressure adjustment screw counter clockwise.

  • Page 78: Annual Maintenance

    Aqua-Hot Maintenance Fluid Circulation Pump Aqua-Hot Maintenance Monthly Maintenance: Failure to disconnect all power supplies and/or to Check the antifreeze and water heating solution to ensure that allow the heater to cool before servicing could cause it is at the proper level by visually checking the solution level in serious damage or personal injury.
  • Page 79 Fluid Circulation Pump Burner Maintenance Aqua-Hot Maintenance Procedure Step 2: Replace the Fuel Filter 1. Locate the fuel filter NOTE: Before performing an annual maintenance, it is 2. Using hose pinch off pliers, clamp off both fuel lines recommended to test run the diesel burner. While testing, going to the fuel filter.
  • Page 80 Fluid Circulation Pump Burner Maintenance Step 2 Be sure to clamp off the fuel supply and return lines at the ports on top of the Aqua-Hot PRIOR to beginning this replacement procedure� Step 4: Remove the Diesel Burner 1. Locate the diesel burner’s controller and disconnect both plugs.
  • Page 81 Fluid Circulation Pump Burner Maintenance Aqua-Hot Maintenance Procedure NOTE: To remove the diesel burner, it maybe necessary to disconnect the ETS Module and High-Limit Thermostats from the diesel burner’s thermostat plug. Step 4: Remove the Diesel Burner (continued) 1. Carefully pull the diesel burner away from the Aqua- Hot 4 - 5 inches before rotating the burner, then remove completely as shown in Figure 138.
  • Page 82 Fluid Circulation Pump Burner Maintenance Step 5: Clean and Inspect the Combustion Chamber and Heat Transfer Tabs (continued) 3. Inspect the Combustion Chamber assembly and Air Swirler for damage or signs of warping. • Inspect the outer ring that the photo disc seats against for signs of warping. •...
  • Page 83 Fluid Circulation Pump Burner Maintenance Step 7: Inspect the Diesel Burner 1. Reinstall the Combustion Chamber assembly and the Air Swirler into the Aqua-Hot. Electrodes Flame Sensor Fuel Nozzle Photo Disc Fuel Pump Grommets Figure 144 Inspect the following: 1. Electrodes 5.
  • Page 84 Fluid Circulation Pump Burner Maintenance Step 8: Clean Ignition Electrodes and Flame Sensor 1. Ignition Electrodes • Polish away any carbon deposits that may have baked onto the metal tips of the ignition electrodes with a coarse sponge 2. Flame Sensor •...
  • Page 85 Fluid Circulation Pump Burner Maintenance Step 9: Replace Fuel Nozzle 1. Use a ¾” wrench to hold the fuel nozzle manifold hex, while loosening the fuel nozzle with a ⅝” wrench and remove. 2. When replacing the fuel nozzle, be sure to tighten the nozzle, loosen it a ¼ turn, and then firmly re-tighten. This will establish a seated fit and avoid any leaks.
  • Page 86 Fluid Circulation Pump Burner Maintenance Step 10: Adjust Ignition Electrodes 1. Using a 10mm socket, slightly loosen the retaining clamp bolt. 2. Place the electrode adjustment gauge on the nozzle manifold hex and insert the metal tips of the ignition electrodes into the appropriate notches of the electrode adjustment gauge.
  • Page 87 Fluid Circulation Pump Burner Maintenance Step 11: Inspect the Photo Disc 1. If the photo disc is not free-floating, the electrode clamp bolt has been over-tightened, and has bent the electrode clamp. Using a 10mm socket, remove the electrode clamp and re-straighten. •...
  • Page 88 Fluid Circulation Pump Burner Maintenance Step 13: Reconnect the Fuel Lines 1. Align the fuel lines on the diesel burner with the fittings on the Aqua-Hot. Using a ” wrench, tighten down both the supply and return fuel fittings. Diesel Fuel Return Diesel Fuel Supply NOTE: Be sure to re-install the fuel lines properly.
  • Page 89 Fluid Circulation Pump Burner Maintenance Step 15: Reinstall the Aqua-Hot’s Access Cover 1. Reinstall the Aqua-Hot’s access cover. NOTE: The access cover must be installed prior to operation as a safety switch (interlock) exists. It will prevent the Aqua- Hot from operating whenever the access cover is not properly installed.

  • Page 90: Cold Weather Operation

    Cold Weather Operation Fluid Circulation Pump Extreme Cold Weather Operation Diesel Burner If the Diesel Burner fails to operate: • Determine if the diesel fuel in the motor home is winter or summer fuel • Verify that the diesel fuel is liquid and not jelled •...

  • Page 91: Fill And Purge Procedure

    Fill and Purge Procedure Fluid Circulation Pump 4. Activate the fluid transfer pump and begin filling the Aqua- Filling and Purging the Aqua-Hot 250-D03 Hot through the fill valve. Before the first activation of the Aqua-Hot, fill the unit with 5.

  • Page 92: Winterization

    Winterizing the Aqua-Hot Fluid Circulation Pump 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. Not winterizing the Aqua-Hot when freezing temperatures are Please follow these instructions when winterizing the Aqua- present will result in serious damage to the Aqua-Hot domestic Hot domestic water heating system.

  • Page 93: General Troubleshooting

    General Troubleshooting General Troubleshooting • Test for unit operation: ○ If the burner fails to operate, proceed to Page 96 to Purpose: begin the diesel burner troubleshooting. ○ If the burner begins to operate at this stage, choose a This section serves to solve common operational problems, troubleshooting guide below based on the issue.

  • Page 94: Lack Of Heat

    General Troubleshooting Lack of Interior Heat starts up. If the pump does not begin to operate, see the procedure on Page 32 for troubleshooting. A lack of interior heat with a functioning burner can be 4. Locate all of the heat exchangers within the RV and attributed to many potential issues in the Aqua-Hot.

  • Page 95: Blue/White Smoke

    General Troubleshooting 250-D03 Unit Smoke 5. Visually inspect this sub-assembly, looking for any damage or leak locations. Purpose: Smoke During the Burn Cycle: It is possible that the Aqua-Hot 250-D03 may smoke upon first start-up. There are many possible causes for smoke as 1.

  • Page 96: Aqua-Hot System

    General Troubleshooting Burner Troubleshooting Diesel Burner Troubleshooting 8. Locate the left and right high-limit thermostats and press the red center button on both thermostats to reset. This section will assist in troubleshooting the Aqua-Hot • Test for continuity on both thermostats. Both should diesel burner.

  • Page 97: System Schematics

    General Troubleshooting System Schematics CONTROLLER PIN OUT REFERENCE NOTE: All connectors are shown from Pin insertion side. ©Aqua-Hot® 250-D03 Diesel Series Service Manual REV 220302 p. 97...
  • Page 98 General Troubleshooting System Schematics 250-D03 Diesel Series Service Manual REV 220302 p. 98 ©Aqua-Hot®...
  • Page 99 General Troubleshooting System Schematics ©Aqua-Hot® 250-D03 Diesel Series Service Manual REV 220302 p. 99...
  • Page 100 General Troubleshooting System Schematics 250-D03 Diesel Series Service Manual REV 220302 p. 100 ©Aqua-Hot®...

  • Page 101: Measuring Antifreeze

    Appendix 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 propylene glycol mixture 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 102: Antifreeze Information

    Antifreeze Types Appendix Antifreeze Types Please note that this is only necessary when mixing concentrated propylene glycol antifreeze with water; suppliers The following information addresses the necessary usage of premixed antifreeze are responsible for the use of high- of a propylene glycol based “boiler” type antifreeze in the quality (distilled, deionized, or soft) water when preparing their Aqua-Hot.
  • Page 103 Antifreeze Appendix protection to the internal metal components of the Aqua-Hot raised, resulting in less freeze protection. Please reference the Hydronic Heating System from corrosion and rust. Antifreeze is attached graphical representation regarding the percentage able to perform this function by the addition of rust and anti- of antifreeze to water and how it directly affects the solution’s corrosive inhibitors, which are designed specifically to activate freezing point.

  • Page 104: Warranty

    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.
  • Page 105 Service Manual SERIES AHE-250-D03 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...

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