Troubleshooting

EcoMAX 613, 618, 622, 635, 824, 828 and 835 Condensing Boilers

Quick Fault Finding Procedure

When troubleshooting your Vaillant EcoMAX boiler please follow the following logical fault finding procedure:

  • Electrical Safety Checks. Check the electrical circuits by testing short circuit, earth continuity and resistance to earth tests. Check correct electrical polarity.
  • Electrical Supply. Ensure that the boiler has electrical supply correct to 230 V.
  • Gas Supply. Check the boiler has gas supply and that it has been purged. Ensure the boiler has an inlet gas pressure of 20 mbar at the gas valve.

Warning: Use only qualified CORGI registered contractors to work on gas boilers.

  • Filling the Heating system. Ensure that the boiler is full of water and charged to 1-1.5 BAR.
  • Control. Ensure main on/off control is set to ‘on’
  • Temperature. Set the heating temperature to the maximum setting.
  • External Controls. Check that the external control display is calling for heat. Ensure that the boiler’s anti-cycling economiser is not engaging.

Checking Status Mode

By checking the status mode you are checking the operation status of your boiler. To check the status mode press the information button designated ‘i’ on your display, and a code will appear indicating the operational status of the boiler. The information on the status codes and what they mean check the table below:

CodeCode MeaningNotes
S.0No Heat DemandHeating Operation
S.1Pump RunningHeating Operation
S.2Pump Running Prior to IgnitionHeating Operation
S.3Ignition SequenceHeating Operation
S.4Burner IgnitedHeating Operation
S.6Heating System Fan Overrun
S.7Pump Over RunHeating Operation
S.8Anti Cycling ModeHeating Operation
S.10Hot Water DemandHot Water Operation
S.11Pump and Fan RunningHot Water Operation
S.13Ignition SequenceHot Water Operation
S.14Burner IgnitedHot Water Operation
S.16Fan OverrunHot Water Operation
S.17Pump OverrunHot Water Operation
S.20Warmstart DemandWarm Start
S.21Pump and Fan RunningWarm Start
S.23Ignition SequenceWarm Start
S.23Burner IgnitedWarm Start
S.26Hot-Water Fan Overrun
S.27Pump OverrunWarm Start
S.28Anti Cycling ModeWarm Start
S.30No Heating Demand from External Controls
S.32Fan Unit Waiting Period
S.34Frost Proctection Mode
S.36No Heating Demand from Low Voltage Controls
S.37Fan Unit Waiting Period
S.39Contact Thermostat has been activatedUnder Floor Systems
S.53Delay Mode due to lack of water in system20 mins
S.54Low Level Water Waiting Period

Checking Diagnosis Codes

By checking the Diagnosis Codes you are able to find the particular fault that your boiler is experiencing. This will give you the information to troubleshoot and conduct the necessary changes or repair to your system. To check the diagnosis mode press the information button ‘I’ and ‘+’ simultaneously and you should see ‘d.0’ in the display. Scroll with the ‘+’ or ‘-‘ keys up or down to the required diagnostic number. When you have arrived at your desired code press the ‘I’ button to interrogate the system. You can also alter the value by pressing ‘+’ or ‘-‘ keys. The values will flash when altering, and to save press and hold the information button ‘i’

For information of what each diagnostic code is refer to the table below:

CodeDiagnosis Code MeaningDisplayNotes
d.0Part Load SettingAdustable Values in KW
d.1Water Pump Overrun1 - 60 minFactory Adjusted to 5 minutes
d.2Maximum Burner anti cycling period at 20¡C flow temperature2 - 60 minFactory Adjusted to 20 minutes
d.5Flow Temperature Setting°C
d.7Warmstart Temperature Setting°CEcoMAX 800 only
d.8External Controls Heat Demand0 = Room Thermostat open (No Demand) 1 = Room Thermostat Closed (Demand)
d.10Pump Status1 = ON 2 = OFF
d.13External Pump Status1 = ON 2 = OFF
d.14External Circulation Pump when fitted1 = ON 2 = OFFEcoMAX 835 Only
d.16Pump SpeedSet Value for Built-in Pump 0 = auto 1 = 53% 2 = 60% 3 = 70% 4 = 85% 5 = 100%EcoMAX 635, 835 Only
d.22Second Pump1 = DHW Circulating Pump 2 = External CH Pump 3 = Vantage Loading Pump 4 = Solar Pump
d.23Summer/Winter Function1 = WINTER 2 = SUMMERControl Knob
d.25Hot-water activation via warm-start clock1 = YES 2 = NO
d.34Current Fan Speed Valverpm/10
d.35Diverter Valve Position0 = Heating system 1 = Hot Water 2 = Mid PositionEcoMAX 800 Only
d.40Actual Flow Temperature°C
d.41Actual Return Temperature°C
d.44Actual Ionisation Current ValueDivide by 100 in Amps
d.46Outside Temperature CorrectionK
d.47Actual Outside Temperature°C
d.60Number Over Heat Cut Off OperationsNumber
d.61Number of Lock OutsNumberNumber of unsuccessfull ignition operations at last attempt
d.67Remaining Anti Cycling PeriodsMinutes
d.68No First StartNumberNumber of unsuccessfull 1st ignition
d.69No Second StartNumberNumber of unsuccessfull 2nd ignition
d.71Maximum Target Value for Heating System40 - 85°CMaximum target value for heating system flow temperature
d.72Pump OverrunSecondsPump overrun period after filling of an electronically controlled hot water tank
d.73Offset Warmstart Temperature Value-15K to +15KFactory adjusted to -5K. Recommended Setting for Solar applications 7°C EcoMAX 800 Only.
d.80Number of Heating System Operating HoursHours
d.81Number of Hot Water System Operating HoursHours
d.82Number of Heating System Cycles (Total)Number
d.83Number of Hot Water System Cycles (Total)Number

Checking Fault Codes

Fault codes only display if your system experiences one of the registered faults. These fault codes will display in priority to all other information on the display. Generally speaking if you have an issue with your boiler you will have some form of fault code displaying automatically. If you do not then refer to the diagnosis codes above. If you have multiple faults then the corresponding fault code s will alternate display every 2 seconds. The system will record the last 10 fault codes, so to see each one press the ‘+’ and‘-‘ keys simultaneously then scroll with the ‘+’ key. To cancel the fault error memory press and hold the ‘i’ key.

For information on each fault code refer to the table below:

CodeFault Code MeaningCause
F.0Flow-NTCFlow-NTC cable defective or broken
F.1Return-NTCFlow-NTC cable defective or broken
F.10Short circuit - Flow NTCNTC plug shorted to casing, NTC Defective
F.11Short Circuit - Return NTCNTC plug shorted to casing
F.13Short circuit in Tank SensorNTC Defective, dhort circuit in cable loom, damp plug connection
F.20Over Heat Cut Off ActivatedMaximum Temperature Exceeded
F.22Low Water or No WaterNo Water in System, Pump Defective or Pump Lead Defective
F.23Water Temperature Low. Temperature Range too WidePump Obstructed, pump running at low capacity, air in applicance, system pressure too low, flow and backflow NTC reversed
F.24Water Temperature Low. Temperature Range too FastPump Obstructed, pump running at low capacity, air in applicance, system pressure too low, flow and backflow NTC reversed
F.25Water Switch. System Pressure Too LowPump Obstructed, pump running at low capacity, air in applicance, system pressure too low, flow and backflow NTC reversed
F.27No Demand to Gas ValveElectronic Board Defective, Gas Valve Defective
F.28Boiler Goes To Lock OutNo Gas, Insufficient gas, Incorrect gas valve adjustment, electrode defective, ignition lead defective, electronic ignitor defective or check air inlet duct
F.29Flame Extinguished re-ignition unsuccessfullGas supply or Check Flue Duct
F.32Fan Turning speed MalfunctionFan Unit Obstructed, plug-in fan connector not correctly inserted, hall sensor defective, fault in cable loom or defective electronic control system
F.60Gas valve control + defectiveShort Circuit in cable loom to gas valves, gas valve assembly defective or electronic control system defective
F.61Gas valve control - defectiveShort Circuit in cable loom to gas valves, gas valve assembly defective or electronic control system defective
F.62Defective gas valve closure mechanismLeak in gas valve assembly or electronic falut
F.63EEPROM errorElectronic Falut
F.64Electronic System/sensor FaultShort Circuit in flow or backflow NTC or Electronic fault
F.65Electronic system Temperature too highElectronic System Affected by external heat source or electronic fault
F.67Electronic fault in flame systemElectronic fault

Run a Test Program

By running a test program allows the sequential activation of special functions to test your boiler. The test programs are activated by pressing the Power ‘ON’ switch and ‘+’ simultaneously for 5 seconds. By default ‘P.1’ will display, where you can scroll by pressing the ‘+’ button. Press the ‘I’ button to start the unit and test the selected program. A test program can be aborted at any time by pressing the ‘I’ and ‘+’ buttons simultaneously.

For information on each Test Program refer to the table below:

CodeTest Program Meaning
P.1Test Program used when the unit runs at full load after successful ignition
P.2Test program used when the unit runs with minimum gas consumption after successful ignition
P.5Program for STB (Safety Temperature Limiter) testing; the device heats up, bypassing the regular shutdown procedure, until it reaches the STB shutdown temperature of 97¡C

Parts Replacement

 

Safety First!

Please Note: Use only qualified CORGI registered contractors to work on gas boilers.

  1. Isolate Mains power to your boiler system by either removing the electrical plug at the socket or switching the breaker off or removing the fuse at the breaker/fuse box.
  2. Turn off gas supply to your boiler
  3. When removing any items containing water (Hoses, pipes etc) make sure they do not spill on electrical components
  4. Always replace consumable parts like o-rings and gaskets with new parts
  5. Always test for gas and undertake functional checks of the boiler after doing work to gas carrying components
  6. Always conduct electrical check such as polarity, continuity and resistance to earth with a multimeter before and after any work

Initial Steps

  1. Turn off the boiler
  2. Isolate electric supply to your boiler
  3. Remove the boiler’s bottom cover
  4. Turn off the gas supply
  5. Turn off the CH valves
  6. Turn off the cold water inlet valves (EcoMAX 800 series)
  7. Remove the front cover
  8. Carefully lower the electronic control box
  9. Drain the central heating via the drain points to drop the boiler’s water pressure

Removal of Burner

  1. Remove the screw connecting the air inlet pipe
  2. Disconnect the gas valve union
  3. Disconnect the HT lead and earth lead from spark electrode
  4. Remove the burner manifold by undoing the five nuts
  5. Disconnect the fan and gas valve
  6. Retrieve the complete burner assembly including burner, gas valve and fan
  7. Remove the burner, gas valve and fan from the boiler.

Replacement of Burner

ecomax burner

  1. Turn off the boiler
  2. Remove the front casing
  3. Lower the control box
  4. Remove the burner, gas valve and fan
  5. Remove the four screws shown in (1) above, fixing the burner to the burner manifold
  6. Affix the new burner to the manifold using a new sealing gasket (usually supplied with the new burner), ensuring that the notch in the burner aligns with the burner-viewing window
  7. Reassembly in the reverse order to above
  8. Recommission the boiler as per procedure

Replacement of Fan

  1. Turn off boiler
  2. Remove the front panel
  3. Gently lower the control box
  4. Remove the burner, gas valve and fan assembly
  5. Remove the four screws shown in (1) above
  6. Separate the gas valve and fan assembly from the burner manifold (2) above
  7. Remove the two screws (3) above, securing the gas valve to the fan
  8. Affix the gas valve to the fan to burner manifold using the new sealing gasket which is supplied. Tighten the four screws equally to maintain a good seal.
  9. Reassembly the entire assembly in reverse order
  10. Recommission boiler as per procedure

Replacement of Gas Valve

ecomax gas valve 2

 

ecomax gas valve

  1. Turn off boiler
  2. Remove the front panel
  3. Gently lower the control box
  4. Remove the burner, gas valve and fan assembly
  5. Remove the four screws shown in (1) above
  6. Separate the gas valve and fan assembly from the burner manifold (2) above
  7. Remove the two screws (3) above, securing the gas valve to the fan
  8. Disconnect the gas inlet supply to the gas valve by removing the four screws, and change out with a new gas valve using the new sealing gasket supplied
  9. Refit the gas valve and fan assembly to the burner manifold using the new sealing gasket. Tighten all four screws equally to ensure good seal.
  10. Reassembly the entire assembly in reverse order
  11. Recommission boiler as per procedure. Ensure a combustion analysis is conducted.

Replacement of Central Heating Expansion Vessel

Ecomax expansion tank

  1. Turn off boiler
  2. Remove the front panel
  3. Gently lower the control box
  4. Drain the boiler
  5. Remove the union shown (1) above from the expansion vessel
  6. Remove two screws shown in (2) above and remove the retaining bracket shown as (3) above
  7. Slide the expansion vessel forward to remove it from the boiler
  8. Reassembly the entire assembly in reverse order
  9. Recommission boiler as per procedure

Replacement of Central Heating Expansion Vessel

Ecomax heat exchanger 1

 

ECOMAX heat exchanger 2

  1. Turn off the boiler
  2. Remove the front panel
  3. Gently lower the control box
  4. Drain the boiler
  5. Remove the burner, gas valve and fan assembly as above
  6. Disconnect the condensate drain by removing the clip shown (4) above, and pulling the condensate drain down shown (5) downwards
  7. Remove the primary flow connection shown (7) from the heat exchanger
  8. Disconnect the primary return connection shown (6) from the heat exchanger
  9. Loosen the nylon nut at the bottom of the heat exchanger
  10. Loosen the two top securing bolts shown (8) and roate the clamps away from the heat exchanger
  11. Remove the bottom screw and securing clamp shown (8)
  12. Pull heat exchanger forward and remove from the boiler
  13. Drain any water from the heat exchanger
  14. Reassembly the entire assembly in reverse order
  15. Recommission boiler as per procedure

Replacement of Electronic Control Board

  1. Turn off the boiler
  2. Remove the front panel
  3. Gently lower the control box
  4. Unclip the back cover from the electronics box and open the cover
  5. Unclip the front cover and remove the cover
  6. Disconnect all the wires to the board
  7. Unclip and remove the circuit board
  8. Remove the display unit and timer (if fitted)
  9. Clip the new circuit board in position, reconnect all the wires and refit the covers
  10. Raise the unit and reinstall the display unit and timer (if fitted)
  11. Recommission boiler as per procedure

The new circuit board must be adapted to the heating unit, therefore follow the instruction in the table below.

CodeDescriptionDisplayed ValuesCircuit Board SettingSetting for EcoMAX 600 seriesSetting for EcoMAX 800 seriesComments
d.0Heating System Part LoadAdjustable values in KW45 kWsystem dependentsystem dependentMUST be adjusted when new
d.1Heating System Pump Overrun1-60min5 minsystem dependentsystem dependentMay be adjusted
d.2Heating system max. off-period1-60min20 minsystem dependentsystem dependentMay be adjusted
d.14Pump speedSet value for built in pump 0(auto), 53, 60, 70, 85, 100 %0 (Auto)system dependentsystem dependentMay be adjusted
d.16External CH pump1, 2, 3, or 41N/A2May be adjusted
d.71Max. target value for heating system flow temperature40 - 85¡C82¡Csystem dependentsystem dependentMay be adjusted
d.72Hot-water pump overrun0 - 250 s80 ssystem dependentsystem dependentMay be adjusted
d.73Difference between warm start and hot-water outlet target value-15 K to +15 K-9 KN/AN/AMUST be adjusted when new