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MIZUDO Tankless Hot Gas Water Heater Installation and Operation Manual

1 Safety Information

This manual has safety information and instructions to help you eliminate or reduce the risk of accidents and injuries.

1.1 Safety Definitions

This manual has safety information and instructions to help you eliminate or reduce the risk of accidents and injuries.

1.2 Safety Warnings and Operation Safety Guidelines

  1. Follow all local regulations, or in the absence of local regulations, follow the current version of the US National Gas Code: US ANSI Z223.1/NFPA 54, and/or CSA B149.1, Natural Gas and Propane Installation Code.
  2. Ground the equipment properly in accordance with all local regulations or without local regulations, using the National Electrical Code: ANSI/NFPA 70 or Canadian CSA standard C22.1 Canadian Electrical Code Part 1.
  3. Carefully plan where you plan to install the water heater. Please ensure: Your water heater will have enough flammable air and proper ventilation. Install the water heater in a location where water leaks do not damage the surrounding area. (See "3.1 Installation Instructions")
  4. Check the gas type, gas pressure, water pressure and rated current on the nameplate. If the unit does not meet your requirements, please do not install and consult the manufacturer.
  5. If any problems occur, turn off all hot water taps and turn off the gas. Then call a trained technician or gas company or manufacturer.

WARNING

WARNING

WARNING

CAUTION

WARNING

This product can expose you to lead, which is known to the state of California to cause cancer and birth defects or other reproductive harm. For more information, go to www.P65warnings.ca.gov.

2 General Information

2.1 Function Introduction and Explanation

The unit is a box less gas fast water heater designed to effectively supply hot water continuously during proper installation.

Read all installation instructions thoroughly before installing this product.

If you have any questions or concerns about this device, please consult the manufacturer or its local agent.

This water heater can only be installed indoors for indoor models.

The model description is listed on the nameplate, which is located on the side panel of the water heater.

The principle of the water heater is shown below:

Diagram illustrating the components of the tankless water heater with numbered labels.

2.2 Dimensions and Connection Points

NOTICE: The images used in this document are for reference purposes only. Components and component locations may vary according to specific product models. Measurements may vary ±0.38 in. (10 mm).

Diagram showing the dimensions and connection points of the water heater.

This series of gas water heaters with solar linkage function by default:

a. When it is detected that the inlet water temperature reaches a predetermined value, the water heater does not start;

b. When the combustion work is started, and the inlet water temperature is less than the set temperature by 4 °F (2°C), the water heater stops working;

c. When the combustion work is started, if the inlet water temperature is ≥ 140 °F (60 °C), the water heater stops working.

Controller temperature adjustment range
System start conditionInlet water temperatureSet temperature-inlet water temperature
Normal combustion conditionsInlet water temperatureSet temperature-inlet water temperature

2.3 Technical Parameters

MODELFDG-CS80FDG-CS100
Natural Gas Input (Operating Range)Btu/hr Min. 11,000 Max. 80,000Min. 11,000 Max. 100,000
Propane Input (Operating Range)Btu/hr Min. 11,000 Max. 80,000Min. 11,000 Max. 100,000
Activation flowrateGPM/min 0.530.53
Rated powerW/A 25 W/0.32 A28 W/0.398 A
StandbyW/A 1/0.031/0.03
Freeze-ProtectionW/A 100/0.85100/0.85
SupplyVAC/Hz 120/60120/60
Gas connectioninch 3/4" NPT3/4" NPT
Water Connections
Water Pressure *PSI (MPa) 15-150 (0.1-1.0)15-150 (0.1-1.0)
Natural gas Inlet Pressure"W.C. (KPa) Min. 3.5 (0.87) Max. 10.5 (2.61)Min. 3.5 (0.87) Max. 10.5 (2.61)
Propane Inlet Pressure"W.C. (KPa) Min. 8.0 (1.99) Max. 13.0 (3.23)Min. 8.0 (1.99) Max. 13.0 (3.23)
Weightlbs (kg) 21.38 (9.7)21.38 (9.7)
Dimensionsinch H 20.5" x W 13.0" x D 7" mm H 520 × W 330 x D 178H 20.5" x W 13.0" x D 7" H 520 × W 330 x D 178
IgnitionElectric IgnitionElectric Ignition
Water heater Category **Category IIICategory III

Not recommended in excess of 2,000 ft. above sea level.

* 15 psi or above is recommended for flow.

** Water heater Category - water heaters of other than direct vent type, for outdoor. installation, are divided into four categories based on static pressure produced in the vent and flue loss.

Category I - a water heater that operates with a non-positive vent static pressure and with a vent gas temperature that avoids excessive condensate production in the vent.

Category II - a water heater that operates with a non-positive vent static pressure and with a vent gas temperature that may cause excessive condensate production in the vent.

Category III- a water heater that operates with a positive vent static pressure and with a vent gas temperature that avoids excessive condensate production in the vent.

Category IV - a water heater that operates with a positive vent static pressure and with a vent gas temperature that may cause excessive condensate production in the vent.

NOTICE: installation, are divided into four categories based on static pressure produced in the vent and flue loss.

2.4 Component Diagram

Diagram showing the components of the water heater with numbered labels.

3 Installation

3.1 Installation Instructions

  1. Follow all local regulations, or in the absence of local regulations, follow the current version of the US National Gas Code: US ANSI Z 223. 1/NFPA 54 or Canada b 149. 1 natural gas, propane installation specifications.
  2. All gas water heaters require proper and careful installation to ensure safe and efficient operation. This manual must be strictly observed.
  3. The manifold pressure is preset at the factory. It is computer controlled and does not require adjustment.
  4. Maintain proper maintenance space when installing equipment. So that it can be easily connected or removed.
  5. The water heater must be installed in a place where it can be used at any time with a suitable amount of flammable air. The indoor water heater can be directly ventilated.
  6. The electrical connection requires disconnecting the unit for maintenance and safety to turn off the power to the water heater.
  7. Do not install the unit where the exhaust vents point to any openings in the building or where noise may disturb the neighbors. Ensure that the vent terminal meets the required distance from any door or opening by local regulations to prevent exhaust gases from entering the building.
  8. Carefully select the installation location of the water heater, lint and fine powder Contaminants such as flour can block the air intake and reduce fan operation. This in turn, can lead to burning anomalies and shorten the life of the water heater. Regularly ensure that the area around the water heater the air inlet are free of dust, debris and other contaminants.
  9. This water heater is for indoor installation only.
    • The water heater requires a 3-inch exhaust pipe. See the subsequent sections for more details.
    • Only install the water heater in a heated area where the temperature cannot be below freezing. The warranty does not cover damage caused by freezing.
    • The water heater must be securely mounted to a wall or other suitable structure.
    • The water heater cannot be installed on the floor.

WARNING

WARNING

WARNING

operate with minimal sound, the manufacturer does not recommend installing the unit on a wall close to the bedroom or in a room for quiet study or meditation.

Place the heater near the drain and the water will not damage the surrounding area. As with any water heating device, there is a real possibility of leakage at certain times during the life of the product. The manufacturer is not responsible for any water damage that may occur. If you install a drain pan under the unit, make sure it does not restrict the flow of combustion air.

NOTICE: The warranty does not cover damage caused by water quality.

3.2 Installation Checklist

4 Operation

4.1 Safe Operation

FOR YOUR SAFETY READ BEFORE OPERATING

WARNING: If you do not follow these instructions exactly, a fire or explosion may result causing property damage, personal injury or loss of life.

A. This appliance does not have a pilot. It is equipped with an ignition device which automatically lights the burner. Do not try to light the burner by hand.

B. BEFORE OPERATING smell all around the appliance area for gas. Be sure to smell next to the floor because some gas is heavier than air and will settle on the floor.

WHAT TO DO IF YOU SMELL GAS

C. Use only your hand to turn the gas shutoff valve. Never use tools. If the valve will not turn by hand, don't try to repair it, call a qualified service technician. Force or attempted repair may result in a fire or explosion.

D. Do not use this appliance if any part has been under water. Immediately contact a qualified installer or service agency to replace a flooded water heater. Do not attempt to repair the unit! It must be replaced!

OPERATING INSTRUCTIONS

  1. STOP! Read the safety information above on this label.
  2. Set the thermostat to lowest setting.
  3. Turn off all electric power to the appliance.
  4. Do not attempt to light the burner by hand.
  5. Turn the gas shutoff valve located on the outside of the unit to the closed position.
  6. Wait five (5) minutes to clear out any gas. If you then smell gas, STOP! Follow "B" in the safety information above on this label. If you don't smell gas, go to the next step.
  7. Turn the gas shutoff valve located on the outside of the unit to the open position.
  8. Turn on all electrical power to the appliance.
  9. Set thermostat to desired setting.
  10. If the appliance will not operate, follow the instructions in "To Turn Off Gas to Appliance" and call your service technician or gas supplier.

TO TURN OFF GAS TO APPLIANCE

  1. Set the thermostat to lowest setting.
  2. Turn off all electric power to the appliance if service is to be performed.
  3. Turn the gas shutoff valve located on the outside of the unit to the closed position.

WARNING: It is absolutely forbidden to use this water heater without installing a smoke exhaust pipe.

DANGER: Steam from flammable liquids can explode and catch fire, causing death or severe burns.

DANGER: Water temperature above 125 °F (52 °C) will immediately cause severe burns or burns.

DANGER: Pressure relief valve hot water supply system unit complying with safety valve and automatic shut-off gas standard, ANSI Z 21. 22-csa 4.4, should be installed at the manufacturer's designated position during installation. Pressure relief device for safe operation of water heaters. Do not disassemble or block the safety valve. No valves shall be provided between the safety valve and the water heater. The relief valve should be placed in a position where it will not cause damage. Also, no other reducer fittings or other restrictions may be placed on the drain line to limit flow. For installation and maintenance of pressure relief valves, see the installation manual heading "Relief Valves" Valve Discharge Lines and other safety precautions.

4.2 Built-in controller

WARNING: Do not store or use gasoline or other flamm-able vapors and liquids in the vicinity of this or any other appliance.

Diagram of the built-in controller with labeled functions.

1. The unit's outlet water temperature setting range is 95 °F (35°C)~149 °F (65 °C).

2. Press "⬆", the temperature will increase. Press this button continuously the temperature increase continuously.

3. Press "⬇", the temperature will decrease. Press this button continuously the temperature will decrease continuously.

4. Press and hold "<0xE2><0x96><0xBD>" in stand by mode to enter the °F/°C switch option.

°F°C°F°C°F°C°F°C°F°CTime to produce serious burn
953510742118481295414060More than 5 minute
963610943120491315514161One and a half to two
983711144122501325614362About 30 seconds
1003811345123511345714563About 10 seconds
1023911446125521365814764Less than 5 seconds
1044011647127531385914965Less than 3 seconds
10541About 1.5 seconds
About 1 seconds

* Factory setting (default): 107 °F(42 °C).

How to use the mixing valve:

  1. Turn on the cold water tap.
  2. Mix hot and cold water to get the proper water temperature.
  3. When the use is over, close the water valve.

5 Troubleshooting

5.1 Diagnostic Codes and Remedies

Before You Call For Service Troubleshooting Tips Save time and money! Review the charts on the following pages first and you may not need to call for service.

This water heater incorporates a variety of shut off devices that prevents the operation of the water heater down if undesirable combustion conditions occur. Such as the presence of a blockage of the combustion air vent insufficient gas or pressure which can impact the safe operation of the water heater. Please contact a Qualified Service Technician if this occurs. When the water heater fails, the display shows the fault code, and the buzzer continuously sends out "B, B, B" alarms. Please follow the table below.

Error CodePossible CauseFault Handling
When the system is turned on or working, the wired controller displays code "EO", and the buzzer alarms the fault.1. The outlet water temperature sensor connector is loose or has poor contact. 2. The outlet water temperature sensor is damaged (open circuit, short circuit or metal parts).1. Clamp the outlet water temperature sensor terminal. 2. Replace the water temperature sensor.
When the system is turned on the working or the working, the displays code "E1" and the buzzer alarms the fault.1. The gas valve is not open. 2. The gas supply pressure or gas composition is abnormal, causing accidental flameout. 3. The igniter, ignition needle is damaged or the line is faulty. 4. Damage to the flame induction needle or wire failure. 5. The combustion system (burner, nozzle, air control panel, proportional valve, sectional valve) is damaged, the specifications are inconsistent or the wiring is wrong, resulting in abnormal combustion. 6. The control program or parameter settings are incorrect, resulting in unstable combustion. 7. The fan speed is abnormal, resulting in unstable combustion.1. Open the gas valve to ensure that the water heater can get normal gas supply. 2. Confirm that the gas type and pressure meet the requirements of the water heater. 3. Check if the igniter, ignition pin and circuit are damaged, and replace the damaged parts. 4. Check if the flame induction needle is damaged and replace the damaged parts. 5. Check if the combustion system is damaged, if the wiring is wrong, and replace the damaged parts. 6. Check whether the program and parameters meet the values in the parameter table. 7. The wind speed of the fan is abnormal. Check whether the program and parameters meet the values in the parameter table.
When the system is turned on, the wired controller displays code "E2" and the buzzer alarms the fault.1. The feedback pin is bent and in contact with other metal parts. 2. The feedback pin plug-in terminal is loose and hits the metal part. 3. Feedback pin wire is broken.1. Replace the ignition feedback needle assembly. 2. Plug the feedback pin terminal correctly and firmly into the feedback pin. 3. Check if the wire is disconnected and replace the wire.
When the system is turned on or working, the wired controller displays code "E3" and the buzzer alarms the fault.1. The thermostat opens or the wire is faulty. 2. The gas supply pressure or gas composition does not match, causing abnormal combustion. 3. The control program or parameter settings are incorrect, resulting in abnormal requirements combustion. 4. The combustion system is damaged or the specifications are inconsistent, resulting in abnormal combustion.1. Check the temperature controller or circuit and replace the damaged parts. 2. Confirm that the gas type and pressure meet the requirements of the water heater. 3. Check whether the program and parameters meet the values of the parameter table. 4. Check the combustion system for damage and replace damaged parts.
When the system is turned on or working, the wired controller displays code "E4" and the buzzer alarms the fault.1. The inlet water temperature sensor connector is loose or has poor contact. 2. The inlet water temperature sensor is damaged (open circuit, short circuit or metal parts).1. Clamp the water temperature sensor terminal. 2. Replace the water temperature sensor.
When the system is turned on or working, the wired controller displays code "E5" and the buzzer alarms the fault.1. The fan signal is not detected or the speed is too low in the system startup 55. 2. During operation, the fan speed is not detected for 25 consecutively, or the speed is too low. 3. The power supply voltage is too low, causing the fan speed to slow down.1. The fan assembly, controller damage or line failure, causing the fan not to run or the speed is too low, check the fan, the main controller is damaged, the wiring is damaged, loose, replace the damaged parts. 2. Confirm whether the power supply and fan voltage meet the design requirements.
During the system working process, the wired controller displays code "E6" and the buzzer alarms the fault.1. The gas supply pressure or gas composition does not match, causing abnormal combustion. 2. The control program or parameter settings are incorrect, resulting in abnormal combustion. 3. The water temperature sensor specifications do not match, the display temperature is much higher than the actual temperature. 4. The combustion system is damaged or the specifications are inconsistent, resulting in abnormal combustion. 5. The heat exchanger fins of the heat exchanger are poorly welded, and the heat transfer is slow. After the water valve is closed, the water in the tube is continuously heated.1. Confirm that the gas type and pressure meet the requirements of the water heater. 2. Check whether the program and parameters meet the values of the parameter table. 3. Test whether the actual water outlet temperature and the wired controller display temperature are close(±3 °C), and replace the wrong outlet water temperature sensor. 4. Check the combustion system for damage and replace damaged parts. 5. Detect if the heat exchanger fins are poorly welded and replace the damaged parts.
When the system is turned on or working, the wired controller displays "E7" and the buzzer alarms the fault.1. The valve connector is loose or has poor contact. 2. The valve is short-circuited.1. Clamp the water temperature sensor terminal. 2. Check if the valve coil is short- circuited and replace the damaged parts.
When the system is turned on or working, the wired controller displays code "E8" and the buzzer alarms the fault.1. During operation, the fan speed continuously exceeds the set value of 5S speed. 2. The outdoor wind pressure is too high, and the fan speed exceeds the upper limit of the speed. 3. A large amount of carbon in the heat exchange fins (when the gas source is used incorrectly), causing blocked, and the fan speed increase exceeds the upper limit of the speed.1. Check if the exhaust passage is blocked. 2. Stop starting, and start after no strong wind in the outdoor. 3. Remove the heat exchanger, use a brush to gently clean the carbon on the fins, and ensure that the type and pressure of the gas used subsequently meet the requirements of the water heater.
During the system working process, the wired controller displays "En" and the buzzer alarms the fault.In order to prevent oxygen deficiency, some models have timing protection. Please turn off the tap and use it after a while.1. Set the appropriate time according to the usage habits, and the timed shutdown time can be set to 20, 30, 40, 50, 60 minutes. 2. It is not necessary to set "OF" to turn off the timing function.

Fault alarm release and reset method: If the above code appears, please check the waterway, the gas path is normal, press "Switch button" to turn off or turn off the power to restart. The water heater is restored to normal use. If the above operations cannot be resumed, please notify the after-sales service personnel.

5.2 Non-defect when the following conditions occur:

Error CodePossible Cause
White smoke at the exhaustWhen the outdoor temperature is too low, the discharged smoke encounters outdoor cold air and condenses into a white mist.
Water is not hotIf the water flow is too low, the water will get cold. The minimum water flow rate is required to be 0.6 gallons per minute. Make sure the water heater is running smoothly.
The water heater suddenly shuts downWhen the water heater is timed, the water heater will automatically shut down. Please wait for a while before using it.
Close the hot water valve, but the fan cannot stop immediatelyThis is a function to delay the fan off, so that the exhaust of the water is finished. Fully drained heaters that ensure user safety.
After the water heater starts, it does notThere is a distance from the water heater to the hot water tap, because the water pipe.
Can have hot water right awayIt still takes some time to use the cold water in the cold water. Water and hot water. The longer the pipeline, the more time it takes.
After the water heater is powered on, the controller does not respond.There is no power input, please check the circuit.

6 Maintenance

The water heater should be checked at least once a year or as necessary by a licensed technician. If repairs are needed, any repairs should be done by a licensed technician. The water heater's lifetime may be extended by regular maintenance.

WARNING:

6.1 Vent System

6.2 Unit Draining and Filter Cleaning

Clean the filter:

Diagram showing filter cleaning procedure.

  1. Remove by turning counter clockwise and then clean and replace.
  2. 1. Turn off the water inlet supply valve. 2. Open a hot water tap to release the line pressure.

6.3 Clean Burners

It is imperative that control compartments, burners, and circulating air passageways of the appliance be kept clean.

Clean as follows:

  1. Turn off and disconnect electrical power. Allow to cool.
  2. Close the water shut off valves. Remove and clean the water inlet filter.
  3. Remove the front panel by removing 4 screws.
  4. Use pressurized air to remove dust from the main burner, heat exchanger, and fan blades. Do not use a wet cloth or spray cleaners on the burner. Do not use volatile substances such as benzene and thinners. They may ignite or fade the paint.
  5. Use soft dry cloth to wipe cabinet.

6.4 Visual Inspection of Flame

Verify proper operation after servicing. The burner must flame evenly over the entire surface when operating correctly. The flame must burn with a clear, blue, stable flame. See the parts breakdown of the burner for the location of the view ports. The flame pattern should be as shown in the figures below.

Diagram showing satisfactory and unsatisfactory flame patterns.

WARNING: Do not check the safety valve when the water heater is in normal operation to avoid hot water burns.

6.5 Pressure Relief Valve Maintenance

WARNING: Testing the pressure relief valve should only be performed by a licensed professional. Water discharged from the pressure relief valve could cause severe burns instantly or death from scalds.

WARNING: Before manually operating the pressure reducing valve, check that the hot water is discharged in a safe place. If water cannot escape from the end of the drain, turn off the air supply and turn off the power and call a qualified person to determine the cause. See the manufacturer of the pressure relief valve for inspection and maintenance requirements.

Diagram illustrating the pressure relief valve setup.

6.6 Freeze Prevention

WARNING: If freezing conditions are expected, turn off water and gas and drain all water from the appliance. If power and the automatic frost protection are connected freezing will be prevented.

1. Turn Water Off

2. Turn Gas Off

3. Turn Off The Power Supply

4. Drain Water

Diagram showing water, drain, gas, and cold connections.

Antifreeze Tips

CAUTION: Please note damages caused by freezing are NOT covered under the tankless water heater warranty as an industry standard. Please make sure to take all the measures to protect your water heater.

6.7 Minimum Load Adjustment Method

Set the temperature on the controller to 35 °C and increase the inlet water temperature so that the outlet temperature is above 35 °C. It then proves that the water heater is operating at its minimum heat load.

6.8 Gas Pressure Test Position

Diagram showing the gas pressure test position.

The gas inlet has a pressure measuring nozzle. The inlet gas pressure can be measured by unscrewing the screw.

CAUTION: Please close the gas valve before connecting the measuring instrument. Avoid accidents such as fires.

7 Wiring Diagram

Diagram showing the wiring of the water heater.

8 Packing List

Check if the following items are included in the water heater.

OrderDescriptionQuantity
1Gas water heater1 piece
2Installation and Operation Manual1 piece
3Perforated Paper1 piece
4Accessories Package1 piece
5Warranty1 piece
6Service Card1 piece
Models: Gen 1 3.6 GPM, 80, 000 BTU, FDG-CS80WNG, FDG-CS80 Tankless Hot Gas Water Heater, Tankless Hot Gas Water Heater, Hot Gas Water Heater, Gas Water Heater, Water Heater

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