Morco FEB-24ED Guide

FEB-24ED TECHNICAL DOCUMENTATION
01-12-08 version 1.0

1- WARNINGS AND PRECAUTIONS ..........................................1
2 - FEATURES ............................................................................................................2
3 - DESCRIPTION OF FUNCTIONING.......................................................................5
3.1.1 General description .......................................................................................................5
3.1.2 Hydraulic Circuit ............................................................................................................4
3.1.2 PCB (Photograph).........................................................................................................9
3.1.3 Gas Circuit .................................................................................................................. 14
3.1.4 Air circuit..................................................................................................................... 18
3.2 - External auto test functions...........................................................................................19
3.3- On board auto test functions and boiler configuration set up........................................26
3.4 -Trouble shooting + lock out codes................................ .................................................32
3.5- Trouble shooting Flow charts..........................................................................................36
3.6- Assembly and disassembly hydraulic unit.......................................................................44
3.7- Functional flow charts..................................................................................................... 47
3.8- PCB Schematic drawing..................................................................................................53

Warnings and precautions
technical
1.- Warnings and precautions
In order for the boiler to function correctly, it is vitally important for the appliance to
be correctly adjusted on installation in accordance with gas installation regulations.
Boiler installation must comply with the conditions described by in the user and
installation manual provided with the appliance
IImportant: Please read the user and installation manual
for this boiler carefully.
1
PLEASE NOTE THAT THE FAULT CODES AND SOFTWARE DIFFER
FROM THE FEB24E FAULT CODES. ALWAYS USE THIS MANUAL FOR
FAULT FINDING AND TROUBLE SHOOTING ON THE FEB24ED

Features
technical
2
2.- Features
The boiler FEB-24EDis a wall hung, room sealed, fan assisted,
microprocessor controlled fully modulating gas combination boiler for providing both
central heating and domestic hot water.
The boiler hasa continuous electronic modulation field. The 24kW boiler has an
output power of between 7.6 kW and 23.7 kW (6,536 and 20,382 Kcal/h).
FEB-24ED
13
5
7
89
4
6
2
12
10
16
15
13
11
14
1. Central heating thermistor
2. Air pressure switch
3. Fan
4. High limit stat
5. Copper heat exchanger
6. Expansion vessel
7. Combustion chamber
8. Ionisation electrode
9. Ignition electrodes
10. Circulation Pump with
Automatic Air Vent
11. Modulating gas valve
12 Hydraulic assembly
13. DHW thermistor
14. Safety valve
15. Pressure gauge
16. Pcb acess panel
17. Control panel
18. Time clock
2
2
3
4
6
7
8
9
10
16
12
1
11
13
14
15
17
18
5

Features
technical
3
Technical data:
Models FEB-24ED
Category II2H3P
Type C12, C32, C42, C52, C82,
B22
Central heating performances Maximum
output kW 23,7
kcal/h 20.382
Minimum
output kW 7,6
kcal/h 6.536
Domestic hot water performances Maximum
output. kW 23,7
kcal/h 20.382
Minimum
output kW 7,6
kcal/h 6.536
Domestic hot water flow 25ºC increase (l/min) 13,6
Domestic hot water flow rate (l/min) 10
(34ºC increase)
Minimum flow rate for activating D.H.W. (l/min) 2
Operating pressure (bar) Maximun Central heating 3
Maximun D.H.W. 10
Minimum D.H.W.activation 0,3
Expansion vessel capacity (L) 7
Temperature selection range (ºC) Central heating
circuit Floor Heating 40-60
Radiators 60-85
D.H.W.circuit 35-60
Gas inlet pressure (mbar) Natural G20 20
Propane G31 37
Gas consumption (Hi) Natural G20 (m³/h) 2,78
Propane G31 (kg/h) 2,1
Electrical suplly (V/Hz) 220-230V~50Hz
Max power consumption (W) 120
Dimensions (mm) Height 680
Width 390
Depth 250
Connections / Interior Ø in (mm) Gas Inlet ¾”/Ø18
Domestic cold water Inlet ½”/Ø15
Domestic hot water Outlet ½”/Ø15
Central heating Flow ¾”/Ø22
Central heating return ¾”/Ø22
Flue gas exit temperature (ºC) 140
Net weight (kg) 29
Gas type Natuaral G20 X
Propane G31 X
CE type examination certificate 99BN794
NOx (according to prNE483) 3
Degree protection IP-44
Directive 92/42/CEE ٭٭
3

Description of functioning
technical
5
3.- Description of functioning
3.1.- General description
3.1.1.- Hydraulic Circuit
Hydraulic Circuit
FEB-24ED
8
9
7
1
3
6
5 2
4
10
26
11
12
1315
14
16
20
21
18 25
19 17 22
24
23
26
1. Expansion vessel
2. Pump
3. Low pressure switch
4. Central heating thermistor
5. Three way valve
6. High limit stat
7. Air pressure switch
8. Venturi
9. Fan
10. Sealed air box
11. Copper heat exchanger
12. Combustion chamber
13. Ignition electrodes
14. Main burner
15. Ionisation electrode
16. Modulating gas valve
17. Gas inlet
18. D.H.W Thermistor
19. Hot water outlet
20. Plate heat exchanger
21. C.H. Flow
22. Cold water inlet
23. C.H. Return
24. Safety valve
25. By-pass
26. C.H.Drain valve
4

Description of functioning
technical
6
Filling the heating circuit:
In order for the boiler to function correctly, the heating circuit pressure must be at
around 1.6b when it is cold.
Both the boiler and the heating installation must be correctly purged,as air in the
water pipes can cause excessive noise and malfunctioning.
The boiler has an automatic drain valve incorporated to the pump body.
The radiators and upper areas of the heating circuit should be provided with an auto-
matic drain valve.
The procedure for correct filling of the installation is as follows:
- Fill the heating circuit by slowly opening the filling valve .
- Close the filling valve when the water pressure gauge shows that a pressure of 1.6
bars has been reached.
- Ensure there is no water leakage from the installation or boiler. Check all the con-
nections thoroughly.
Domestic Hot Water Functioning (DHW):
Water begins to circulate through the domestic circuit of the boiler. The cold water
flows through the 3-way valve, this action ports the 3 way valve and micro switch into
DHW mode.
Water heated in the primary circuit flows through the plate heat exchanger to heat up
the water coming from cold mains water supply. As the cold water circulates, it is
heated up in the plate heat exchanger.
The temperature of the DHW is controled by the DHW thermistor, and limited for safety
Heating Functioning:
The pump starts up and water begins to circulate through the radiator circuit. The fan
and the burner then start up. The heating output temperature is controlled at all times
by the heating thermistor.
Draining the heating circuit:
The boiler has a drain valve incorporated for drai-
ning the heating circuit when necessary. The safety
valve mustn’t be used for this purpose.
5

Description of functioning
technical
7
Description and function of the hydraulic components:
Compact hydraulic unit: (Part number MCB2190)
This unit consists of various hydraulic components: circulating pump, safety valve,
drain valve, plate heat exchanger, 3-way valve, flow restrictor, automatic drain valve
and automatic bypass. All these together form a compact unit.
Radiators
Hot water outlet
Return
Primary heat
exchanger
Primary heat
exchanger
1
5
6
23
4
1. Pump 4.Plate heat exchanger 7. DHW Thermistor
2. Pressure relief valve 5.Three way valve
3. Draining valve 6.Automatic air vent
Circulating pump head:(Part number MCB3050)
Operates in both CH and DHW mode. Circulation of the primary circuit either to the
radiators or to the plate heat exchanger when operating in DHW mode.
Pump combines a manual and automatic anti-blocking system
The capacity of this pump has a mamometric head of 5 metres for the 24kW boiler.
Safety valve:
Also called an overpressure valve, Its function is to prevent the heating circuit exceed
ing 3.0b pressure. DO NOT USE FOR DRAINING BOILER
CO
cold water
inlet
DHW THERMISTOR
7
6

Description of functioning
technical
8
Drain valve:
This component allows the heating circuit to be drained.
Finger operated located to the right hand side of the
safety valve. (Part number MCB2180)
3 Way valve:
Integrated within hydraulic unit, operates whenever a hot
tap is opened.
This action activates the micro switch and ports the primary
circuit away from the radiators to the plate heat exchanger
In order to produce hot water at the taps.
(Part number MCB2190 Complete unit)
Micro switch
Located on the 3 way valve brass diaphragm housing. Activation
ocours when the white switch tip which sits on the diaphragm
push rod in CH mode is released as the diaphragm push rod
ports the 3 way valve to DHW.
This action places the PCB into DHW mode allowing the boiler
to commence the ignition sequence.(Part number MCB2320)
Flow restrictor
Located within the hydraulic unit between the brass inlet
union and the cold inlet port on the hydraulic unit.
This component restricts the flow of water into the boiler
to 10 litres per min.(Part number MCB2240)
NOTE
THIS RESTRICTOR IS NOT SUPPLIED WITH NEW
HYDRAULIC UNITS. ALWAYS ENSURE THAT THIS ITEM
IS REPLACED INTO THE HYDRAULIC UNIT IF ANY WORK IS
CARRIED OUT ON THE HYDRAULIC UNIT
MCB2240
MCB2320
MCB2180
7

Description of functioning
technical
9
Expansion vessel: (Part number MCB2005)
The expansion vessel is a hermetically closed receptacle with two chambers separa-
ted by an SBR membrane. One chamber contains nitrogen (air) and the other is filled
with the water from the heating circuit. It has a capacity of 7 litres.
The function of the expansion vessel is to absorb the increase in volume of the hea-
ting circuit water when it is heated up.
The amount of expansion by the expansion vessel depends on the temperatu-
re selected by the user for the heating circuit,and on the total volume of the heating
circuit.
Automatic bypass:
The bypass is located inside the hydraulic unit. It joins the heating outlet and return.
It is preset, only opening when the pressure between the bypass inlet and outlet exceed
0.3 b
Its purpose is to assist when there is a large loss of load in the circuit and the pump
consequently has difficulty in moving the water. When the bypass opens, an amount
of water which was flowing towards the radiators is made to circulate directly to the
return pipe, thus making the work of the pump easier.
Central heating low pressure switch: (Part number FCB1480)
This indicates the pressure inside the heating circuit
is correct. If the pressure is under 0,5 bar the switch
opens and the boiler locks out (F3)
The expansion vessel pressure is 1 bar, with zero pressure in
the heating circuit
I
FCB1480
8

Description of functioning
technical
10
3.1.2.- Main P.C.B (Part number MCB3000)
1 DHW ANTI-FREEZING RELAY (J24) (NOT USED ON FEB-24ED)
2 GAS VALVE 1 RELAY. EV1 (J25) (220VAC)
3 GAS VALVE 2 RELAY. EV2 (J25) (220VAC)
4 PUMP RELAY (J17)
5 FAN RELAY (J18)
6 “Opto triac” SPARKS(J25)
7 TRANSFORMER (Ionisation. 70-80V AC)
8 TRANSFORMER(MAIN BOARD FUNCTIONS)
9EARTH
10 MICROPROCESSOR. CONTROL
11 PUSH BUTTON FOR TEST
12 (J4) DIGITAL INPUTS (AIR PRESSURE SWITCH,H.L.THERMOSTAT, …).
13 (J8) LOW PRESSURE SWITCH
14 (J6) DHW AND HEATING THERMISTORS, ROOM THERMOSTAT, EXTERNAL PROBE
15 (J22 OR J23) DISPLAY PCB CONNECTOR (3 PURPLE WIRES)
16 (J16) MODULATING GAS VALVE (18VDC)
17 (J27) PORT FOR SOTWARE PROGRAM
18 AUTO TEST PORT
19 SUPPRESSION FILTER
20 SUPPRESSION FILTER
21 MAIN ELECTRICAL SUPPLY CONECTORS (230V, 50Hz)
9
J22
J18
J17
J25
N
N
L
L
L
L
N
N
L
FAN 230V ac
PUMP 230V ac
MAINS SUPPLY
230Vac
18
GAS VALVE
EV1 230V ac
EV2 230V ac
SPARK 230V ac
85v ac
18v dc return micro switch
18v dc out micro switch
18v dc return air pressure
18v dc out air pressure
18v dc return HL stat
18 v dc out HL stat
18v dc return LPS
18v dc out LPS
TIME CLOCK 0UT 18 v dc
TIME CLOCK RETURN 18vdc

Description of functioning
technical
11
Anti Freeze Safety:
When the temperature (read by heating
thermistor) falls to 6ºC the pump will run until the
temperature reaches to 9ºC. If the temperature
continues to fall and the heating thermistor
reads less than 3 ºC the boiler will light up at
minimum power until the heating circuit
temperature reaches 20º C after that the pump
runs for a further 30 minutes. After the pump has run for 1 hour the PCB
reads the temperature if it is between 3º and 6º C the pump will stop running
If the burner is burning for over 3 hours, the control circuit stops the burner, reads the tem-
perature and if the temperature is lower than 3 degrees the burner will relight.
Pump Antiblock safety: (Keep fit)
If during during the last 23 hours the pump has
not run the PCB will run the pump for 30 seconds
Overheating:
If the heating thermistor detects a lower tempera-
ture than 50ºC and there is a higher output than 95%
after 5 minutes the boiler will shut down then relight
Fuzzy logic
This program operates only in central heating mode the principal purpose is to detect the
size of the heating load connected to the boiler and to reduce unnecessary gas use.
In heating demand the boiler will only operate at minimum burner pressure for (4.0mb
propane) for the 1st 30 seconds after the flame is established.
After this period of minimum burn the boiler will then modulate to increase the power to
the heating system if required.
.
Output
Time
30sec.
9
10

Description of functioning
technical
Output
Time
If the heating selected temperature is achieved in less than 5 minutes.The next heating
cycle will result in the minimum burn period to be extended to 5 mins.
If the burner continues to burn at minimum power for 5 minutes without restarting the
Modulation process can then start to increase the burner power if required.
If during the 5 minutes at minimum power the boiler shuts down, the above sequence is
repeated.
Set point Security
When the boiler is working in D.H.W., with the burner lit with at least the minimum
power, and the DHW energy requirment is lower than the minimum power.
The above situation will result in the following if DHW temperature is greater than
DHW selected temp (+ 8º C ) or+ 4º C for more than 15 seconds then the boiler
starts to work in ON-OFF cycling mode.
While the boiler is in ON-OFF mode, the boiler starts at least 8 seconds and stops
working for; at least, 4 seconds, and always working at the minimum power. The
boiler comes out of this ON-OFF mode when DHW temperature is lower than DHW
set point - 4º C or when DHW temperature is lower than DHW set point during more
than 45 seconds and the boiler begins to regulate again
85º C Security
While DHW is working, if the temperature of the primary circuit reaches 85º C,
the boiler will limit (by modulation) not to go over 85º C. This security works while DHW
temprature is lower than DHW selected temprature.
88º C Security
While DHW is working, if the temperature of the primary circuit arrives up to 88º C
the gas valve closes and the burner will shut down, the pump continues to run in order
to reduce the temperature of the primary circuit. When the temperature of the primary
circuit reaches at DHW selected temperature + 20º C the boiler will relight and modulate.
11

Description of functioning
technical
13
92º C Security (without DHW demand)
If heating thermistor value arrives to 92º C, the pump will run making cycles of 10 se-
cond starting and stopping. If the temperature remains high the pump will continue
cycling until a lower temperature is detected.
180 minutes security:
When the burner is working continuously for 180 minutes, the burner will shut down
for a period and if it is necessary, the burner will relight.
Control and safety components:
Main PCB:
This circuit governs the correct functioning of all the boiler functions.
High limit thermostat: (Part number MCB2250)
This is in direct contact with thethe main heat exchanger (dry pocket)
It controls the temperature of the outlet circuit, protecting the boiler against overhea-
ting. It cuts out at 102º C.
The contacts of this thermostat are normally closed. When the thermostat is activa-
ted, the boiler will lock out (F4 block). The thermostat resets automatically,
although the F4 fault will need resetting from the control panel.
Thermistors:
There are two thermistors incorporated to the boiler. The DHW thermistor is screwed
into the 3 way valve at the hot water outlet, and is in direct contact with the hot water
exiting the boiler. (Part number FCB1080 ) faulty or out of range
thermistors will cause the boiler to lock out with F11.(N.B. the boiler
will only read the values of this thermistor when working in hot
water mode)
The central heating thermistor is located on the left hand side of the
primary heat exchanger. This thermistor controls the temperature of
the primary circuit within the boiler.
The thermistor is also responsible for first stage over heat protection
any overheating within the boiler is detected and controlled by the pump
cycling in 10 second intervals until a lower value is reached.
The thermistor also reads the temperature for the built in frost protection.
Faulty or out of range thermistors will cause the boiler to lock out (F13)
(Part number MCB2245)
FCB1080
DHW
C.H.
HL STAT
12
MCB2245

Description of functioning
technical
14
Note: When the heating is working and within the range shown in the table below
If the thermistor is out of range the boiler will lock out, automatically “resetting” again when
the working range is entered. In case DHW is working the boiler continues work even if the
led displays fault. The boiler uses the heating thermistor to regulate DHW temperature.
Relation between Temperature-Voltage and
Thermistor nominal Resistance
Temperature
(ºC)
Voltage
(Volts)
Resistance
(k)
85 0.92 1.44
80 1.01 1.65
75 1.15 1.91
70 1.28 2.21
65 1.41 2.57
60 1.54 2.99
55 1.71 3.51
50 1.93 4.13
45 2.13 4.87
40 2.34 5.78
35 2.55 6.89
13

Description of functioning
technical
15
3.1.3.- Gas Circuit
Characteristics of the gas components:
Gas valve: (Part number FCB1130)
This is one of the most important components of the boiler. It
regulates output power, gas consumption, combustion, mo-
dulation.
The SIT-845 SIGMAvalve is equipped with two on/off safety
valves powered by the PCB at 230V AC, plus a modulating
valve also powered by the PCB in DC ensuring continuous
modulation.
The valve has two test nipples (A) is the inlet supply pressure
(B) Is the outlet pressure from the modulating section of the valve
(Burner pressure can also be tested at the inlet pipe to
the burner)
Spark generator
A
B
This component has 2 functions the 1st is to create a
high tension voltage at the spark electrodes. The unit also
provides a connection for the 230v ac from the PCB to
the twin gas valve solenoids (EV1 +EV2)
(Part number MCB3055)
Gas pressure modulation:
This is a progressive modulation type boiler, i.e. it automatically adjusts its gas con-
sumption to the USER’s needs at all times.
When the boiler needs to heat water at maximum power, there is maximum gas pres-
sure to the burner and, inversely, when modulation is at a minimum it uses minimum
power and the pressure to the burner is also minimum.
The gas pressure to the burner varies according to the gas type (propane/ natural)
FCB1130
14

Description of functioning
technical
1
FEB-24ED:
Installation Menu.
To enter in the Installation menu, with the left
knob out of the O position and the right knob
must be placed in to the middle, more or less
at 75ºC, after the boiler must be turned off,
turned on, turned off again and finally turned
on again, using the left knob, in every move-
ment you cannot stay more than 3 seconds
and it’ll appear “- -” at the display, and before
5 seconds, the right knob must be moved to
the minimum (“summer” position) and them
the display shows “P1” and another value
alternately.
To move between different steps, the left knob (DHW) is used and to change the se-
lected step’s value, the right knob (CH) is used. When the right knob (CH) is in sum-
mer position, the display shows the stored value of the selected step.And it is pushed
the main board button when a new value wanted to be stored, then the display shows
“- -” to indicate that the value has being stored. To leave installation menu it can move
the right knob back to the O position.
These are the 7 Installation Menu´s Steps:
Step 1. Select gas type. The display shows “P1” and the value selected “6n” or “LP”.
“6n” is for Natural Gas and “LP” for propane/butane. When the gas type is stored the
value of the maximum and minimum power will automatically change. When the right
knob (CH) is in summer position, the display shows the stored value of the selected
step. And must be pushed the main board button when a new value wanted to be
stored, then the display shows “- -” to indicate that the value has being stored.
15
MAIN BOARD PUSH BUTTON
N.B
Gas change requires that the correct injectors for the gas type are replaced, and the adjustment of
the maximum and minimum pressures on the gas valve and the correct electrical values to be set on
the PCB.

Description of functioning
technical
19
Step 2. Maximum Heating Power. The display shows “P2” and the value selected
alternatively. When the right knob (CH) is in summer position, the display shows the
stored value of the selected step.And must be pushed the main board button when a
new value wanted to be stored, then the display shows “- -” to indicate that the value
has being stored. The value is limited between 20 and 99.
Step 3. Post-Circulation time of the pump after an ambient thermostat cut-off. Display
shows “P3” and the selected time (when right knob is in summer position). Default
value is 1 minute and it can be changed with right knob until 85 minutes. To store the
selected value use the main board push button.
Step 4. Type of heating circuit (radiators or floor heating). The display will show P4
and it will alternate between this P4 and the selected option, RA(radiator) or SU (floor
heating). Using right knob (CH) RA (radiators) or SU (floor heating) can be selected.
In case floor heating (SU) is selected, the set point must be stored. Using the right
knob (CH) it can be selected the value between 40 and 60 ªC and using the main
board button the value will be stored and the display will show “- -” again to indicate
that the value has being stored. When this option (SU) is chosen, the right knob (CH
set point) won’t be able to select the CH set point in normal operation; it will be always
the stored value in the configuration menu.
Step 5. External Probe. Display shows “P5” and “X” the selected curve alternatively.
If SE=0 no external probe will be connected. In all the other cases(“A”, “b”, “C” or “d”)
it will be selected the best option for the external probe. To store the value, use the
main board push button.
Step 6. Flue System Cleaner. Display shows “P6” and a hot water tap must be ope-
ned to activate this function. It’ll turn the boiler on and set the maximum power to
clean the flue system.
Gas Type Maximum Power Minimum Power
Natural Gas 74% 35%
Propane 92% 46%
16

Description of functioning
technical
20
The table below shows the gas pressure values at the burner for each model of
boiler:
OUTPUT (kcal/h) BURNER PRESSURE IN
mbOF WATER GAUGE
BOILER 24KW
Natural Propane
20382 18.0 35.0
18060 13.3 27.0
16340 11.2 23.0
14620 8.6 19.0
12900 7.0 14.8
11180 5.3 11.9
9460 4.0 8.6
7740 2.3 5.8
6536 1.3 3.2
Ignition Pressure 4.0 8.0
Ø Injectors (mm) 1,14 0,75
Important: It is very important to know that when you are mak-
ing the gas regulation you may use the values of this table.
The values should be equal or lower never higher. For example
if you are making a maximum natural gas regulation the
table says 18.0mbso you achieve 18.0mb or less than 18.0mb
I
Changing the gas:
This boiler is designed to function using PROPANE GAS or NATURAL GAS
GAS.
To change the type of gas used, the only com-
ponents that need to be changed are the injec-
tors. The injectors corresponding to the gas to
be used are fitted as shown in Table 3.
After the injectors have been changed, the gas
is to be adjusted depending on the type used,
as shown in Table 3.
- Maximum pressure adjustment (@Gas valve)
- Minimum pressure adjustment (@Gas valve
- Ignition pressure adjustment (see step 5 T5 adujusting boiler parameters)
using built in auto test feature)
17

Description of functioning
technical
21
3.1.4- Air Circuit
Characteristics of the air circuit components:
Fan: (Part number MCB2030)
The function of the fan is to draw in air from the outside and evacuate the burnt gases
produced during combustion.The 24kW boiler fan has a power of 35W.
Part number MCB2030
Air pressure switch: (Part numberMCB2105)
This component ensures that the fan is running, that there are
no obstructions anywhere in the flue or in the flue venturi, also
checks that the flue is installed and working correctly
24kW boiler -> 140/89Pa pressure switch
If a pressure switch is calibrated to 140/89 Pa, for example, this means that the pres-
sure switch contacts are activated at a differential pressure of 140Pa (1.4 mb) and
deactivated at 89Pa (.89 mb).
To measure the differential pressure, first measure the pressure using the water co-
lumn in one of the Venturi gauges, and then with the water column in the other. The
result will be the sum total of both.
This data is to be taken as an approximate value only, as variations of a few Pascals
occur in the measurements while the fan is running.
Flue Venturi : (Part number MCB2100)
This is fitted to the fan outlet pipe. When the air or flue gases
flow through it, a pressure difference is produced which must
be great enough to activate the differential air pressure switch.
PLEASE NOTE THAT DURING PERIODS OF SHUT DOWN. THE
FLUE VENTURI MAY BECOME BLOCKED WITH INSECTS.
IT WILL BE NECESSARY TO REMOVE AND CLEAN THE VENTURI..
THE VENTURI WILL ONLY FUNCTION CORRECTLY WHEN FITTED
WITH THE LONGEST PART FACING UPWARDS(- TO TOP)
+
-
MCB2105
18