Morco GB24 Operating instructions

12/2023
UIN 236461 A02
User & Installation Instructions
GB24 & GB30
IV
Propane
88
restart
Morco House, Riverview Road, Beverley, East Yorkshire, HU17 0LD
Morco Products Ltd
Tel: [phone] Email: [email protected]
k
Website: www.morcoproducts.co.uk
To Domestic Hot Water:
GB24-Propane Minimum 8.0 kW
GB30-Propane Minimum 8.0 kW
GB24-Propane Maximum 24.2 kW
GB30-Propane Maximum 30.3 kW
To Central Heating:
GB24-Propane Minimum 8.0 kW
GB30-Propane Minimum 8.0 kW
GB24-Propane Maximum 24.2 kW
GB30-Propane Maximum 24.2 kW
BOILER OUTPUT
min max min max
mode
off
e
restart
IV

2
MODEL
SYMBOL UNITS 24 30
Condensing Boiler n/a n/a yes yes
Low Temperature Boiler n/a n/a no no
B1 Boiler n/a n/a no no
Cogeneration Space Heater n/a n/a no no
Equipped with a Supplementary Heater n/a n/a no no
Combination Heater n/a n/a yes yes
Nominal Heat Output for Space Heating
Full Load P4kW 24.3 24.3
Part Load P1kW 8 8
Auxiliary Electricity Consumption
Full Load elmax kW 0.029 0.03
Part Load elmin kW 0.022 0.014
Standby PSB kW 0.003 0.003
Seasonal Space Heating Energy Efciency
Full Load ƞ4% 90 90
Part Load ƞ1% 98.7 98.7
Standby Loss Pstby kW 0.05 0.05
Ignition Pign kW 0 0
Emissions Gross NOxmg/kWh 50 51
Annual Energy Consumption QHE GJ 75 75
Sound Power Level, Indoors LWA dB 46 46
Domestic Hot Water
Domestic Hot Water Qelec kWh 0.166 0.017
Water heating energy efciency (Eco)
Tapping Prole L
ƞWH %82 80
Daily fuel consumption 24hr (GCV) Actual
measured
Qfuel kWh 14.53 14.85
Annual electricity consumption AEC kWh 36 36
Annual fuel consumption AFC GJ 11 11
ERP DATA
 
All Gas Safe Register installers carry a Gas Safe Register ID card, and have a registration number. You can check your installer by calling Gas Safe
Register direct on 0800 4085500.

3
MORCO IV COMBINATION BOILER
Morco Products Ltd
ERP DATA
SYMBOL UNITS MODEL
24 30
Condensing boiler Yes
Seasonal Space heating efciency class A
Rated heat output kW 24
Seasonal space heating energy efciency ƞs% 94*
Annual energy consumption QHE GJ 75
Sound power level, indoors LWA dB 46 46
Water heating energy efciency class A
Seasonal Space Heating Energy Efciency of the Boiler *%
Temperature control (from che of temperature control) %
Class I Class II Class III Class IV Class V Class VI Class VII Class VIII
1% 2% 1.5% 2% 3% 4% 3.5% 5%
PRODUCT FICHE
 
The energy efciency of the package of products provided for in this document may not correspond to its actual energy efciency once installed in a
building, as the efciency is inuenced by further factors such as heat loss in the products in relation to the building size and its characteristics
Collector Size
(in m2)
Tank Volume
(in m3)
Collector
Efciency
(in %)
Tank rating
A* = 0.95
A = 0.91
B = 0.86
C = 0.83
D-G = 0.81
Solar Contribution (from che of solar device)
Seasonal Space Heating Energy Efciency of Package TOTAL: A+B+C=
Seasonal Space Heating Energy Efciency Class of Package
= (‘III ’x + ‘IV ’ x ) x 0.9 x ( / 100 x = %
%
GG F E D C B A A+ A++ A+++
< 30% ≥ 30% ≥ 34% ≥ 36% ≥ 75% ≥ 82% ≥ 90% ≥ 98% ≥ 125% ≥ 150%
A
B
C

4

5
Combination Boiler
Morco GB24 & GB30 IV
CONTENTS
1 Users Instructions................................................................................................................................................................ 6
2 Specications .................................................................................................................................................................... 10
3 Technical Data................................................................................................................................................................... 12
4 General Installation Requirements .................................................................................................................................... 14
5 Installation Instructions ..................................................................................................................................................... 16
6 Commissioning Instructions............................................................................................................................................... 25
7 Servicing Schedule............................................................................................................................................................ 27
8 Fault Codes ....................................................................................................................................................................... 33
9 Combustion Checks .......................................................................................................................................................... 39
10 Warranty Conditions .......................................................................................................................................................... 41
Destination Country:
CAT II2H3P (20/37 mbar)
CH = Switzerland
CZ = Czech Republic
ES = Spain
FR = France
GB= UK
GR= Greece
IE = Ireland
IT = Italy
PT = Portugal
SI = Slovenia
CAT I3P (30 mbar)
DE = Germany
NL = Netherlands
CAT I3P (37 mbar)
BE = Belgium
NL = Netherlands
PL = Poland

6
SECTION 1 - USERS INSTRUCTIONS
1 USERS INSTRUCTIONS
1.1 INTRODUCTION
The Morco GB IV is a wall mounted, room sealed, condensing
combination boiler, featuring full sequence automatic spark
ignition and fan assisted combustion.
Due to the high efciency of the boiler, condensate is produced
from the ue gases and this is drained to a suitable disposal
point through a plastic waste pipe at the base of the boiler. A
condensate ‘plume’ will also be visible at the ue terminal.
The Morco GB IV is a combination boiler providing both central
heating and instantaneous domestic hot water.
1.2 SAFETY
Current Gas Safety (Installation & Use)
Regulations or rules in force.
In your own interest, and that of safety, it is the law that this boiler
must be installed by a Gas Safe Registered engineer in the UK, in
accordance with the above regulations.
In other countries the installation must be carried out by a
qualied and competent Gas Installer. In the approved country
the boiler is installed, this must be in accordance with their current
rules in force.
It is essential that the instructions in this booklet are strictly
followed, for safe and economical operation of the boiler.
IMPORTANT. These appliances are UKCA & CE certicated
for safety and performance. It is, therefore, important that no
external control devices, e.g. ue dampers, economisers etc.,
are directly connected to these appliances unless covered by
these Installation and Servicing Instructions or as otherwise
recommended by Morco in writing. If in doubt please enquire.
1.3 ELECTRICITY SUPPLY
This appliance must be earthed.
Supply: 230 V ~ 50 Hz. The fusing should be 3A.
1.4 IMPORTANT NOTES
This appliance must not be operated without the casing
correctly tted and forming an adequate seal.
If the boiler is installed in a compartment then the
compartment MUST NOT be used for storage purposes.
If it is known or suspected that a fault exists on the boiler then
it MUST NOT BE USED until the fault has been corrected by a
Gas Safe Registered Engineer or in other countries a qualied
and competent Gas Installer.
Under NO circumstances should any of the sealed
components on this appliance be used incorrectly or tampered
with.
This appliance can be used by children from 8 years
and above and persons with reduced physical,
sensory or mental capabilities or lack of experience
and knowledge if they have been given supervision
or instruction concerning use of the appliance in
a safe way and understand the hazards involved.
Children shall not play with the appliance. Cleaning
and user maintenance shall not be made by children
without supervision.
Children should be supervised to ensure that they
do not play with the appliance.
In cases of repeated or continuous shutdown a Gas Safe
Registered Engineer, or in other countries a qualied and
competent Gas Installer, should be called to investigate and
rectify the condition causing this and carry out an operational test.
Only the manufacturers parts are to be used for replacement.
1.5 MINIMUM CLEARANCES
Clearances of 165mm above, 100mm below, 2.5mm at the sides
and 450mm at the front of the boiler casing must be allowed for
servicing.
Bottom clearance
Bottom clearance after installation can be reduced to 5mm.
This must be obtained with an easily removable panel, to provide
the 100mm clearance required for servicing.
1.6 TO OPERATE THE BOILER
Refer to Boiler Controls
TO START THE BOILER
Start the boiler as follows:
1. Check that the electricity supply to boiler is off.
2. Set the mode knob (C) to ‘OFF’.
3. Set the Domestic Hot Water temperature knob (A) and Central
Heating temperature knob (B) to ‘e’.
4. Ensure that all hot water taps are turned off.
5. Switch on electricity to the boiler and check that all controls,
e.g. timer and room thermostat, are on.
6. Set the mode knob (C) to ‘ ’ (winter).
The boiler will commence ignition sequence, supplying heat to the
central heating, if required.
Note. In normal operation the boiler status display (D) will show codes:
00 Standby - no demand for heat.
CH “80
†
”Central Heating being supplied
H “60
†
” Domestic hot water being supplied
F P “10
†
” Boilerfrostprotection-boilerwillreiftemperatureis
below 5ºC.
†
= temperature shown for example purposes only
During normal operation the burner on indicator (F) will remain
illuminated when the burner is lit.
Note: If the boiler fails to light after ve attempts the fault code
will be displayed (refer to Fault Code page).
1.7 RESTART PROCEDURE
To restart the boiler, press the restart button. The boiler will repeat
the ignition sequence if a heat demand is present. If the boiler
still fails to light consult a Gas Safe Registered Engineer, or in
other countries a qualied and competent Gas Installer.
FOR ANY QUERIES PLEASE RING THE
MORCO CONSUMER HELPLINE : 01482 325456
NOTE. To restart the boiler press the restart button. The boiler will repeat the ignition sequence if a heat demand is
present.

7
SECTION 1 - USERS INSTRUCTIONS
1.8 OPERATION
Winter Conditions - (Central Heating and Domestic Hot Water required)
Set the mode knob (C) to ‘ ’ (winter).
The boiler will re and supply heat to the radiators but will give
priority to domestic hot water on demand.
Summer Conditions - (Domestic Hot Water only required)
Set the mode knob (C) to ‘ ’ (summer).
Set the central heating demand on the external controls to OFF.
Boiler Off
Set the mode knob (C) to ‘OFF’. The boiler mains power supply
must be left on to enable frost protection (see Frost Protection).
Note.Thepumpwilloperatebrieyasaself-checkonceevery24
hours, regardless of system demand.
Control of water temperature
Domestic Hot Water
The DHW temperature is limited by the boiler controls to
65oC maximum at low draw-off rate, adjustable via the DHW
temperature control (A).
Due to system variations and seasonal temperature uctuations
DHW ow rates/temperature rise will vary, requiring adjustment
at the draw off tap : the lower the rate the higher the temperature,
and vice versa.
Approximate temperatures for domestic hot water:
Knob Setting Hot Water Temperature (approx.)
Minimum 40ºC
Maximum 65ºC
Central Heating
The boiler controls the central heating radiator temperature to a
maximum of 80oC and a minimum of 30ºC, adjustable via the CH
temperature control (B).
The boiler is a high efciency combination boiler which is most
efcient when operating in condensing mode.
The boiler will operate in this mode if the CH temperature control
(C) is set to the ‘e’ position (economy mode). This control should
be set to maximum for very cold periods.
1.9 TO SHUT DOWN THE BOILER
Set the mode knob control to “off”.
1.10 WINTERISATION
If the holiday home or park home is to be left unoccupied during
cold periods when there is a threat of freezing, the domestic hot
and cold water circuits must be drained as follows:
- Turn off the cold water supply
- Open all hot and cold water taps
- Open all drain plugs in the hot and cold water system (do not
drain the central heating circuit, which should have been lled
with antifreeze if installed in a caravan holiday home or park
home).
For more detailed information on winterisation please refer to:
• The winterisation fact sheet under troubleshooting at www.
morcoproducts.co.uk
• The holiday home owners handbook
Please note there are no drain plugs on the boiler. Leave all taps
and drain plugs open until next use to allow any residual water to
continue to drain.
When installed in a Caravan Holiday Home or Park Home the
heating circuit and radiators should be lled with an approved
antifreeze (see section 4.8). The level of antifreeze should
be checked annually by a competent person. If the home is
occupied during very cold and freezing weather, the central
heating should be run continuously and the room stat or
thermostatic radiator valves set at a minimum of 15ºC.
If the home is unoccupied for even a short period, the hot and
cold water system must be drained down. This is the only way to
guarantee against frost damage.
ALL FROST DAMAGE IS OUTSIDE OF THE WARRANTY.
1.11 BOILER OVERHEAT PROTECTION
The boiler controls will shut down the boiler in the event of
overheating. Should this occur, a fault code L1 will be displayed.
Refer to fault chart.
1.12 FLAME FAILURE
Should this occur a fault code F2 / L2 will be displayed. Refer to
fault chart.
continued . . . . . .
8 8
restart
min max min max
mode
off
e
restart
IV
A
K
J BFD GE CH
1.13 BOILER CONTROLS
Legend
A. Domestic Hot Water Temperature Knob
B. Central Heating Temperature Knob
C. Mode Knob
D. Boiler Status Display
E. Function Button
F. Burner ‘on’ Indicator
G. Restart button
H. Central Heating Economy Setting
J. Pressure Gauge
K. Timer

8
SECTION 1 - USERS INSTRUCTIONS
1.14 LOSS OF SYSTEM WATER PRESSURE
The pressure gauge indicates the central
heating system pressure. If the pressure is
seen to fall below the original installation
pressure of 1-2 bar over a period of time then
a water leak may be indicated. In this event
re-pressurise the boiler. If unable to do so or
if the pressure continues to drop a Gas Safe
Registered Engineer, or in other countries a
qualied and competent Gas Installer should
be consulted.
INDICATED BY “F1” (LOW WATER PRESSURE) - THE BOILER
WILL NOT OPERATE IF THE PRESSURE HAS REDUCED TO
LESS THAN 0.3 BAR UNDER THIS CONDITION.
1.15 CONDENSATE DRAIN
This appliance is tted with a siphonic condensate trap system
that reduces the risk of the appliance condensate from freezing.
However should the condensate pipe to this appliance freeze,
please follow these instructions:
a. If you do not feel competent to carry out the defrosting
instructions below please call your local Gas Safe Registered
Engineer, or in other countries a qualied and competent Gas
Installer for assistance.
b. If you do feel competent to carry out the following instructions
please do so with care when handling hot utensils. Do not attempt
to thaw pipework above ground level.
If this appliance develops a blockage in its condensate pipe, its
condensate will build up to a point where it will make a gurgling
noise prior to locking out an “L2” fault code. If the appliance is
restarted it will make a gurgling noise prior to it locking out on a
failed ignition “L2” code.
To unblock a frozen condensate pipe;
1. Follow the routing of the plastic pipe from its exit point on the
appliance, through its route to its termination point.
Locate the frozen blockage. It is likely that the pipe is frozen
at the most exposed point external to the building or where
there is some obstruction to ow. This could be at the open
end of the pipe, at a bend or elbow, or where there is a dip in
the pipe in which condensate can collect. The location of the
blockage should be identied as closely as possible before
taking further action.
2. Apply a hot water bottle, microwaveable heat pack or a warm
damp cloth to the frozen blockage area. Several applications
may have to be made before it fully defrosts. Warm water can
also be poured onto the pipe from a watering can or similar.
DO NOT use boiling water.
3. Caution when using warm water as this may freeze and cause
other localised hazards.
4. Once the blockage is removed and the condensate can ow
freely, restart the appliance. (Refer to “To Operate the boiler”)
5. If the appliance fails to ignite, call your Gas Safe Registered Engineer,
or in other countries a qualied and competent Gas Installer.
Preventative solutions:
During cold weather, set the ‘radiator symbol’ to maximum. (Must
return to original setting once cold spell is over.)
Place the heating on continuous and turn the room stat down to 15ºC
overnight. (Return to normal after cold spell.)
1.16 ESCAPE OF GAS
Should a gas leak or fault be suspected contact the Gas Supplier
without delay. TURN OFF ALL GAS SUPPLIES.
Do NOT search for gas leaks with a naked ame.
1.17 CLEANING
For normal cleaning simply dust with a dry cloth.
To remove stubborn marks and stains, wipe with a damp cloth
and nish off with a dry cloth.
DO NOT use abrasive cleaning materials.
1.18 MAINTENANCE
The appliance should be serviced at least once a year by a Gas Safe
Registered Engineer, or in other countries a qualied and competent
Gas Installer.
1.19 MECHANICAL 24 HOUR TIMER
PROGRAMMING THE TIMER
1. Decide what times you would like the timeswitch to switch ON and OFF.
2. Push segments towards the programme ring for an OFF period and
push away from ring for an ON period. The minimum switching
interval is 15 minutes and this can be increased in 15 minute steps.
3. Bring the timeswitch into the correct condition by manually turning
the programme ring clockwise through a 24 hour cycle.
4. Turn the programme ring clockwise until the correct time of day on
the ring lines up with the time indicator.
Note. The segment dial can be turned when the time controller is
operating. In case of power failure, re-adjust the time controller to the
correct time of day, turning the dial in a clockwise direction.
Permanent Override
By rotating the central switch so that the symbol (1) lines up with the
operating mode indicator ( ) the unit will be permanently ON.
With the symbol ( ) lining up with the operating mode indicator ( ) the
unit acts as a timeswitch.
With the symbol ( ) lining up with the operating mode indicator ( ) the
unit will be permanently OFF.
Permanently o Permanently on
Time Indicator
Align current time to arrow
Timer Control
Operating Mode Indicator
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
O
N
P
e
r
i
o
d
O
N
P
e
r
i
o
d

9
SECTION 1 - USERS INSTRUCTIONS
1.20 POINTS FOR THE BOILER USER
Note. In line with our current warranty policy we would ask that you check through the Troubleshooting guide to identify any problems
externaltotheboilerpriortorequestingaserviceengineersvisit.Shouldtheproblembefoundtobeotherthanwiththeappliancewe
reservetherighttolevyachargeforthevisit,orforanypre-arrangedvisitwhereaccessisnotgainedbytheengineer.
YES
YES
NO HOT WATER
Check the mains switch (fused
spur) is turned on and ensure
switch mode control knob (C) is
in the summer or winter position
Is hot water coming out of the
hot water tap when turned on?
NO CENTRAL HEATING
Check the mains switch (fused
spur) is turned on and ensure
switch mode control knob (C) is
in the winter position
Does the boiler operate and
provide central heating?
Check the time settings on the
programmer are as you require
and adjust if necessary
Check the timer is in an
permanently “ON” position and
the room thermostat is turned up
NO HOT WATER OR
CENTRAL HEATING
Check the fused spur is turned
on and ensure switch mode
control knob (C) is in the winter
position
See boiler “Operation Modes”
and “Fault Codes” section
Does the boiler have a display
showing on the front control
panel?
See boiler “Fault Codes”
section. If ‘00’ is displayed
then follow warranty procedure
if your appliance if under
warranty, or contact a Gas
Safe Registered Engineer, or in
other countries a qualied and
competent Gas Installer, if out of
warranty
YES
NO
Contact a Gas Safe Registered
Engineer, or in other countries
a qualied and competent Gas
Installer
NO
See boiler “Operation Modes” and
“Fault Codes” section. If “00” is
displayed then contact a Gas Safe
Registered Engineer, or in other
countries a qualied and competent
Gas Installer
NO
Contact a Gas Safe Registered
Engineer, or in other countries
a qualied and competent Gas
Installer
1.21 TROUBLESHOOTING
1.22 OPERATION MODES
Note. The display alternates between display code and current temperature
DISPLAY CODE ON BOILER DESCRIPTION
The boiler is in standby operation awaiting either a central heating call or hot water
demand.
The boiler has a call for central heating but the appliance has reached the desired
temperature set on the boiler.
The boiler has a call for hot water but the appliance has reached the desired
temperature set on the boiler.
The boiler is operating in central heating mode.
The boiler is operating in domestic hot water mode.
The boiler is operating in frost protection. Note that after the boiler has reached
temperature it will show “dH” for 60s whilst it also protects the DHW circuit.
The boiler mode knob (C) is in the off position, rotate fully clockwise for hot water and
central heating operation.
00
80
80
60
60
1 0
CH
CH
H
FP
--
H
†
†
†
†
†
† = temperature shown for example purposes only.

10
SECTION 2 - GENERAL SPECIFICATIONS
2 SPECIFICATIONS
2.1 GENERAL SPECIFICATIONS
The Morco GB IV range of boilers are wall mounted, full
sequence, automatic spark ignition low water content, fanned ue,
high efciency condensing combination boilers.
Note. Due to the high efciency of the boiler a plume of water
vapour will be visible from the terminal during operation. The
boiler is supplied for use with Propane only at 37mbar (30 mbar
for DE/NL - refer to Countries of Destination) supply pressure. It
is particularly suitable for caravan holiday home and park home
use.
Maximum heat output in heating mode for the GB24 is 24.2 kW
with 24.2 kW available for hot water production.
Maximum heat output in heating mode for the GB30 is 24.2 kW
with 30.3 kW available for hot water production.
The boiler can be supplied with a standard concentric ue with
additional extensions, ue deector and vertical ue kits available
as optional extras. The only ue that can be tted are those
detailed in this instruction manual.
The boiler is suitable for connection to fully pumped, sealed
heating systems ONLY. Adequate arrangements for completely
draining the system by provision of drain cocks must be provided
in the installation pipework.
The boiler contains the following components:
Cast Aluminium Heat Exchanger
Domestic Hot Water Plate Heat Exchanger
Diverter Valve
Circulating Pump
Pressure Gauge
Pressure Relief Valve and Central Heating Expansion Vessel
Automatic Bypass
Daily Pump and Diverter Valve Exercise
Mechanical 24hr Timer
The boiler temperature controls are visible, located in the control
panel. These enable the user to control both CH and DHW
temperatures independently. Operating and fault codes are
displayed on the status panel.
8
11
18
5
19
9
12
4
15
6
2
1
13
7
3
14 10
16
17
1. Expansion Vessel
2. Pump
3. Pressure Relief Valve
4. Water Pressure Switch
5. Flow Thermistor
6. Return Thermistor
7. Diverter Valve
8. Fan
9. Venturi
10. DHW Plate Heat Exchanger
11. Ignition / Detection Electrode
12. Gas Valve
13. Siphon / Trap
14. DHW Flow Turbine
15. Sump Cover
16. Injector Housing
17. Gas Cock
18. Burner
19. Cast Aluminium Heat Exchanger
2.2 SCHEMATIC DIAGRAM