Morco FEB-24E UK Technical & Faultfinding Manual Download Page 1

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FEB-24E UK SUPERCOMPACT

COMBINATION BOILER

TECHNICAL & FAULTFINDING GUIDE

Morco Products Ltd
Riverview Road, Beverley, East Yorkshire, HU17 0LD
Telephone 01482 325456 Fax 01482 212869

Summary of Contents for FEB-24E UK

Page 1: ...1 FEB 24E UK SUPERCOMPACT COMBINATION BOILER TECHNICAL FAULTFINDING GUIDE Morco Products Ltd Riverview Road Beverley East Yorkshire HU17 0LD Telephone 01482 325456 Fax 01482 212869 ...

Page 2: ...2 Contents 1 Quick Guide to Trouble Shooting 2 Electrical Components 3 Central Heating Logic Programme 4 Explanation of Self Diagnostics 5 Self Diagnostic Flow Charts ISSUE NUMBER 1 0 ...

Page 3: ...er Any blockage will reduce flow and may prevent the boiler firing up HOT AND COLD WATER CONNECTIONS Connections may be reversed at the boiler inlet outlet fittings resulting in the boiler failing to commence ignition sequence This is because the hydraulic valve operates in one direction only THERMOSTATIC SHOWER MIXER VALVE Faulty non return valves within the mixer tap may allow mains cold water t...

Page 4: ...maximum 10 litres min This can be adjusted at the faucet If max flow cannot be achieved through the faucet there is either a blockage or the water supply is inadequate CENTRAL HEATING SYSTEM Check the following first ROOM THERMOSTAT if fitted Faulty connections or incorrectly wired room thermostats result in the central heating not working The fault is usually at the room thermostat but can also o...

Page 5: ... under expansion vessel If the leak is impossible to detect then the last resort is to introduce a proprietary leak sealing chemical into the system such as Fernox LS 3 TIME CLOCK Check that the time clock is calling for heat the white tappets should be in the outer position at the arrow head IMPORTANT The specification of time clocks on boilers after serial number 050512656 incorporates a three p...

Page 6: ... close one of the valves on the working radiator Other radiators should now slowly start to heat up Radiators which fail to heat up may require purging as above 4 If time is not a problem simply leave the heating on After an hour or two the problem will clear itself COLD RADIATORS These usually appear in pairs due to crossed pipe work i e one radiator is fed with two flow pipes with a second radia...

Page 7: ...s the general operating system in the central heating mode and the sequence of events if temperatures exceed the specified limits Please note that following the initial 30 seconds of minimum output modulation may not occur for a further 5 minutes if the central heating logic programme is operating This is because the boiler will not fire on full power if it has detected it is serving a system with...

Page 8: ...pplicable By reading this information and testing before replacing components the correct diagnosis can be reached ensuring that the wrong part is not replaced unnecessarily Fault Finding Flow Diagrams Pages 39 46 These diagrams help diagnose problems that are not related to the safe operation of the boiler and hence are not subject to the lock out mechanism and the corresponding self diagnostic f...

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Page 11: ...11 2 Electrical Components Electrical Circuit Diagram ...

Page 12: ...id page 17 16 Ionisation Electrode page 18 17 High Limit Thermostat page 18 21 Domestic Hot Water Thermistor page 18 22 Central Heating Thermistor page 19 23 Central Heating Low Pressure Switch page 20 25 Green LED Burner On page 20 26 Red LED Lockout Fault Indicator page 21 30 Time Clock page 21 S1 Boiler Model Selector Bridges FEB 24E Make S2 Boiler Model Selector Bridges FEB 24E Make S3 Boiler ...

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Page 14: ... draws 55 watts and runs on 220 230v ac It is operated by relay number 1 and fed from J10 blue brown wires non polarised It must be earthed at the fan and at the PCB 5 CENTRAL HEATING CIRCULATION PUMP The pump operates in both central heating and domestic hot water modes Supply voltage is 230V ac fed from J9 on the PCB blue brown Always operate at number 3 speed If power is supplied to the boiler ...

Page 15: ... from the gas valve N B Care must be taken when replacing the unit not to damage or bend the pins on the gas valve solenoid 7 8 GAS VALVE SOLENOIDS The gas valve is fitted with twin solenoids moulded into a single removable unit In order for the gas valve to open and allow gas to the burner both of the solenoids must be energised The supply voltage for this action is 230V ac and supplied from J8 r...

Page 16: ...perating in the D H W mode In standby mode the supply voltage to the switch is 22V dc from J4 blue In operation the voltage is 12 2V dc returning to the P C B to J4 brown 11 AIR PRESSURE SWITCH The air pressure switch proves that the fan is running and creating enough air flow through the boiler for combustion The correct operation of the switch is dependant on the plastic venturi which is located...

Page 17: ...movable panel on the under side of the electronics box Voltage is fed from the PCB J4 22V dc left hand black and returns to the PCB J4 right hand black via the time clock terminals 4 and 1 Voltage reduces to 12 5V dc when clock and thermostat contacts are both closed N B Loose or poorly connected room thermostat link wires at the connector block will cause problems with the heating demand and will...

Page 18: ...the boiler will require the lockout fault 3 to be manually reset at the control panel before it will resume normal operation N B The thermostat is dry mounted on the heat exchanger you can remove without draining down Never loosen or tighten using the electrical spade terminals 21 DOMESTIC HOT WATER THERMISTOR The thermistor screws into a wet pocket under mains water pressure at the hot outlet sid...

Page 19: ...tects the temperature of the heating circuit primary circuit in D H W mode and provides the initial over heat protection for the boiler at 105 C with fault 6 displayed A faulty thermistor affects both the central heating and hot water A thermistor that is out of range or open circuit will cause the boiler to lock out fault 12 As the thermistor cools and re enters normal operating range reset will ...

Page 20: ...nals from the switch voltage from the switch terminals may short to boiler pipe work and damage the PCB 25 GREEN LED POWER ON BURNER FUNCTIONING The green LED has two display modes A constant green light indicates the boiler is ready to supply hot water or central heating on demand A flashing green light indicates the burner is firing and operating in either hot water or central heating mode Volta...

Page 21: ... ac supply from the electrical filter to drive the motor within the clock The second supply is the low voltage switching supply for the heating demand Supply voltage to the clock switching circuit is fed from J4 22V dc left hand black via the room thermostat connector block to the micro switch on the clock Contact number 4 When the contacts in the clock are in the closed position heating on voltag...

Page 22: ...arked with control 205 or control 204 DESCRIPTION OF THE PCB While the PCB can appear complex and difficult at first understanding its operation and how to test voltages can result in a speedy resolution of any problems The next few pages will guide you through the basic operation of the PCB without the need for a degree in electronic engineering A basic knowledge of electricity and a digital mult...

Page 23: ...voltage is supplied to the external controls components responsible for detecting demand and safe operation of the boiler Ignition sequence will not begin if A Demand from external controls is not detected B A component is faulty or out of range temperature detection C Lock out occurs before any ignition sequence commences ELECTRICAL COMPONENT TESTING The PCB contains sensitive electronics and sof...

Page 24: ...es switching at the relative component in order for the lighting up sequence to activate In the case of the micro switch 21V DC is supplied from J4 second wire from right and assuming water is flowing through the hydraulic valve then the signal voltage will be switched and returned to the PCB at J4 first wire on the right This principle also applies to the external controls e g the time clock and ...

Page 25: ...f the temperature selected at the control panel is not achieved WITHIN 5 minutes the normal modulation will resume in order to achieve the desired temperature see fig 2 IMPORTANT NOTE It is not possible for the user to over ride the logic program during either the initial 30 seconds of the heating sequence or during the subsequent 5 minutes running on minimum burner pressure Adjusting the temperat...

Page 26: ...26 Central Heating Logic Programme Figure 1 Figure 2 ...

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Page 30: ... operation of the boiler This occurs before any ignition sequence takes place If any component is found to be faulty or out of a predetermined range then lock out will be displayed Each fault code begins and finishes with the red LED illuminated for 5 seconds the relevant fault is then indicated by the number of 1 second flashes which occur between the initial 5 second flash and the closing 5 seco...

Page 31: ...ne 1 second flashes Gas valve control circuit failure 10 Ten 1 second flashes Domestic hot water thermistor failure 12 Twelve 1 second flashes Central heating thermistor failure FAULT CODES FAULT 0 Flame Fails to Establish Flame Fails After Ignition 5 seconds 5 seconds The FEB 24E will attempt 3 times to establish main burner flame each ignition sequence will last 6 seconds with a 5 second pause b...

Page 32: ...ll take place after 15 seconds of demand taking place If the contacts are in the normal stand by position i e open then the PCB will initiate the fan As sufficient air flows through the plastic venturi located in the fan spigot a differential pressure is produced and transferred via the silicon tubes to the air pressure switch The contacts in the air pressure switch make and the ignition sequence ...

Page 33: ... reset as temperature reduces but manual reset of the boiler will be required at the control panel POSSIBLE CAUSES Central heating thermistor faulty or not attached to pipe work Primary heat exchanger needs venting loosen automatic air vent cap Faulty high limit thermostat Faulty Connections at PCB FAULT 4 Printed Circuit Board Failure 5 seconds 1 sec 1 sec 1 sec 1 sec 5 seconds The PCB incorporat...

Page 34: ...seconds Overheat protection is maintained electronically via the central heating thermistor which polices the primary water circuit within the heat exchanger and operates in both domestic hot water and central heating modes Further overheat protection is provided by the high limit thermostat which operates on an electro mechanical principal POSSIBLE CAUSES Lock out takes place if the temperature o...

Page 35: ...osed 1 A high residual temperature within the combustion chamber 2 The distance between the ionization electrode and the burner being too short see below 3 Environmental conditions such as supply voltage or humidity Extensive testing has determined that if the boiler has failed with F9 and the gas solenoids are working correctly potential reoccurrence can be avoided by replacing the ionization ele...

Page 36: ... the boiler will continue to run the fan to avoid the possibility of gas build up within the boiler It is not possible to stop the fan running by switching off the boiler by the control panel Only by isolating the boiler from the mains electrical supply will the fan stop running Also if the boiler is in F9 then it is not possible to reset the lockout by the control panel The P C B must be replaced...

Page 37: ...f 10 one second flashes This may result in an incorrect fault code being observed A Complete fault code must have a 5 second flash at the Start and the End of the sequence FAULT 12 Central Heating Thermistor Failure Clip on Type 5 seconds twelve 1 second flashes 5 seconds If the values of the central heating thermistor are out of range lock out will occur until values return to operational levels ...

Page 38: ... or Pump working Spark at the electrode Spark no flame Flame fails after ignition Modulates correctly Noisy Out Go to 1 CH works Go to 2 Go to 3 Go to 4 Go to 5 Go to 6 Go to 7 Go to 8 No Yes No No Yes Yes Yes Yes No Yes No Yes Yes No No No No Yes ...

Page 39: ...ectrical filter 230V ac at the 2 way connector J11 on the main PCB Boiler works No No No No No Yes Yes Yes Yes Yes 1 Check the wiring and the connections between the main PCB and the front panel control PCB If the wiring is correct replace the front panel control PCB 2 Replace the main PCB Boiler works but no green L E D Displayed Replace the front panel control PCB Check the wiring and connection...

Page 40: ...s from the front panel control PCB to the main PCB o k Turn on the heating selector to the maximum position Check for correct operation of the clock room thermostat and the wiring and connections of the above rectify or replace clock or thermostat as necessary Remake the connections from the front panel control PCB to the main PCB Replace the front panel control PCB Replace the main PCB No No No N...

Page 41: ...t cold inlet Non activation of 3 way valve can be caused by blockage within the unit venturi or diaphragm failure rectify fault or replace hydraulic unit see notes on thermostatic shower mixing valves before repairing or replacing 3 way valve 13v dc at J4 on PCB brown blue Replace DHW micro switch Temporarily connect a DHW thermistor screw in type does the boiler work Replace the DHW thermistor Ar...

Page 42: ...ck that the pump impellor spins freely if OK then replace the pump head Check the values of the front panel control PCB and the wiring and connections to the main PCB if these are correct replace the main PCB Are the air pressure switch contacts in the open position No electrical continuity through the air pressure switch Is there a 230v ac supply voltage to the fan check at J10 on the PCB Check t...

Page 43: ...k electrode wires from the spark generator Is there a spark between the terminals on the spark generator Replace the spark generator Check that the tubes to the air pressure switch are not kinked or crossed Top tube to P1 on air pressure switch Bottom tube to P2 on air pressure switch If all connections are Correct then replace the air pressure switch Check the venturi tube for blockages caused by...

Page 44: ...ut locking out Replace front control panel PCB Replace solenoids EV1 EV2 or spark generator as required Replace the gas valve adjust the new valve to the correct gas pressures Check the ignition pressure 8 0mbar if ok check all the main burner jets for blockages boiler works Simulate the ionisation signal with a diode or replace ionisation electrode Boiler works Check the min burner pressure remov...

Page 45: ... pump J9 Blue brown Replace the DHW thermistor Are the values of the DHW thermistor OK Replace the main PCB Replace pump head Is the pump speed set at max speed 3 Set Pump to number 3 speed Clean descale or replace the DHW plate heat exchanger Measure the CH temp is it higher than 85 C and the DHW temp lower than the selected temp Check the wiring and the values of the front panel control PCB CH v...

Page 46: ... to 1 6bar and ensure all air is removed from boiler Check the burner pressures and that the pump speed is set to max speed number 3 Rectify as required Boiler quiet Is the CH thermistor connected securely to the correct pipe work Rectify if not Is the boiler quiet Boiling sounds in the primary heat exchanger after DHW use is associated with scale deposits in the primary heat exchanger Descale hea...

Page 47: ...figure 7 Open a hot tap Adjust the maximum burner pressure chart 1 Using a 10mm spanner rotate the nut E of the gas valve figure 5 Rotating clockwise increases the burner pressure Adjust the variable resistance P1 rotating it anti clockwise until the burner pressure starts to drop Set the minimum burner pressure Open a hot tap Disconnect one of the modulating electro valve terminals on the gas val...

Page 48: ...adjustment Figure 7 Burner pressure mbar inch wg Output kW Natural Propane Natural Propane 23 7 18 0 35 0 7 2 14 0 7 6 2 0 4 0 0 8 1 6 Ignition Pressure 4 0 8 0 1 6 3 20 Ø Injectors mm 1 14 0 75 1 14 0 75 Figure 5 E Figure 6 T Figure 4 C Chart J2 J19 J1 P1 S4 P3 P2 S3 S1 J5 J11 J9 J10 J8 Figure 2 Figure 3 E D ...

Page 49: ...49 MORCO PRODUCTS LTD MORCO HOUSE RIVERVIEW ROAD BEVERLEY HU17 0LD TEL 01482 325456 FAX 01482 212869 ...

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