Marco MT Series User manual

1000762#, 763#, 764#, 765#, 766#, 1762#, 1763# Service Manual for REVIEW
MT Boiler Range –Service Manual
1000762# 1000763# 1000763F#
1001762# 1001763#
1000764# 1000765#
1000766#
ww.marcobeveragesystems.com
Ireland Tel: [phone]
UK Tel: [phone]

1000762#, 763#, 764#, 765#, 766#, 1762#, 1763# Service Manual for REVIEW
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CONTENTS:
1. INTRODUCTION .............................................................................................................................3
2. SAFETY INSTRUCTIONS..................................................................................................................3
3. SPECIFICATIONS.............................................................................................................................4
4. INSTALLATION ...............................................................................................................................5
4.1 MT Boiler Installation .........................................................................................................................5
4.2 Filter Installation.................................................................................................................................7
5. BOILER SETUP................................................................................................................................8
5.1 Operating Boiler for the First Time.....................................................................................................8
6. OVERVIEW & OPERATION .............................................................................................................9
6.1 MT Boiler Operation...........................................................................................................................9
6.2 MT Dual Tap Boiler Operation......................................................................................................... 10
7. SERVICE SET UP ...........................................................................................................................12
7.1 Changing Temperature.................................................................................................................... 12
7.2 Filter Mode ...................................................................................................................................... 13
7.3 Changing from Celsius to Fahrenheit .............................................................................................. 14
7.4 Heat Fill Selection ............................................................................................................................ 15
7.5 Power Selection............................................................................................................................... 16
8. ROUTINE MAINTAINENCE/INTERNAL ACCESS ............................................................................17
8.1 Top Lid Removal .............................................................................................................................. 17
8.2 Lower Front Panel Removal............................................................................................................. 17
8.3 Draining the tank............................................................................................................................. 18
8.4 PCB replacement ............................................................................................................................. 18
8.5 Dispense Tap removal ..................................................................................................................... 19
8.6 Heater Element Removal................................................................................................................. 19
8.7 Level Probes - Cleaning & replacement........................................................................................... 21
8.8 Triac Replacement........................................................................................................................... 22
8.9 Inlet solenoid Replacement............................................................................................................. 23
8.10 De-scaling the tank.......................................................................................................................... 24
9. DIAGNOSTICS...............................................................................................................................25
10. ELECTRICAL SCHEMATICS............................................................................................................26
10.1 Wiring Diagram................................................................................................................................ 26
11. PART DIAGRAMS & LISTS.............................................................................................................29
11.1 MT4, MT8, MT8F parts .................................................................................................................... 29
11.2 MT8DT parts.................................................................................................................................... 30
11.3 MT25 parts ...................................................................................................................................... 31
11.4 MT30 parts ...................................................................................................................................... 32

1000762#, 763#, 764#, 765#, 766#, 1762#, 1763# Service Manual for REVIEW
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1. INTRODUCTION
The information provided in this manual is intended to assist in the installation and maintenance of
the Marco Mix Boiler range. Please read the instructions carefully to prevent accidents and ensure
an efficient installation.
This manual is not a substitute for any safety instructions or technical data affixed to the machine
or its packaging. All information in this manual is current at the time of publication and is subject to
change without notice.
Only technicians or service providers authorised by Marco should carry out installation and
maintenance of these machines.
Marco accepts no responsibility for any damage or injury caused by incorrect or unreasonable
installation and operation.
2. SAFETY INSTRUCTIONS
When using electrical appliances, basic safety precautions should always be followed to prevent
the risk of fire, electric shock, burns, or other injuries or damages.
• Read all operating and safety instructions carefully.
• This appliance must be placed/installed on a horizontal flat stable surface.
• The ambient temperatures this appliance should operate within 5°C - 35°C (41°F –95°F).
• This appliance may be placed in self-service areas if attended to by trained personnel.
• Risk of flooding, the hose supplied with the boiler is non-toxic food quality tested to 190psi.
However, a hose is not a permanent connection. It is, therefore, advisable to switch off boiler and
close the stopcock valve when boiler is not in use, e.g. overnight etc.
• The utmost care has been taken in the manufacture and testing of this machine. Failure to install,
maintain and / or operate this machine according to the manufacturer’s instructions may result
in conditions that can cause injury or damage to property. If in any doubt about the serviceability
of the machine always contact the manufacturer or your own supplier for advice.
• This machine is not intended for use by persons (including children) with reduced physical,
sensory, or mental capabilities, or lack of experience and knowledge, unless they have been given
supervision or instruction concerning use of the machine by a person responsible for their safety.
• Children should be supervised to ensure that they do not play with the machine.
• In the event any wires are damaged, such wires can only be replaced by experts or professional
after service staff from the manufacturer after service department or similar function
departments.
• CAUTION - Risk of fire and electric shock. Only to be used with manufacturer’s specified power
cord set. Marco p/n 1501506, 1501487 (USA), 1501488 (EU), 1501489 (UK/Ire).
• This appliance should not be installed in an area where a water jet could be used to clean it.
• Access to the service area of the appliance is restricted to persons having knowledge and
practical experience of the appliance and the relevant safety and hygiene requirements.

1000762#, 763#, 764#, 765#, 766#, 1762#, 1763# Service Manual for REVIEW
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3. SPECIFICATIONS
BOILERS:
MT4 –
1000762#
1001762#
MT8 –
1000763#
1001763#
MT8DT –
1000764#
MT25 –
1000765#
MT30 –
1000766#
Performance
Immediate Draw Off (L)
Total Hourly output
(L/hr)
4L
28
8L
28
8L
28
25L
28
30L
56
Electrical
Mains Connection
Earthed Mains Plug to IEC 230V
(UK –BS1363)
(EU –CEE7)
(US 230V –NEMA L6-20P)
(US 120V –NEMA 5-15)
Rating
@230V
2.8kW
13A
@120v
1.5kW
13A
@230V
5.6kW
30A
Plumbing
Fittings
Required Pressure
0.75” BSP (or 9/16”-24 UNEF for US versions) food grade inlet hose
supplied.
14.5 –145 psi (100-1000 kPa)
14.5 –87psi (100-600kPa) machines with built-in filter
Dimensions
Height (mm)
Width (mm)
Depth (mm)
464
202
436
589
202
436
690
272
570

1000762#, 763#, 764#, 765#, 766#, 1762#, 1763# Service Manual for REVIEW
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4. INSTALLATION
4.1 MT Boiler Installation
Electrical Installation:
When installing the machine, always observe the local regulations and standards. The appliance is
supplied with a moulded power cord. A suitable mains power supply socket should be available
within easy access of the appliance so that it can be disconnected easily after install.
Plumbing Installation:
•Mains water pressure required (limits): 14.5 –145psi (100 –1000kPa) 1.0 –10.0 bar except
machines with built-in water filter: 14.5 –87psi (100-600kPa) 1.0 –6.0 bar.
•Fit a stop Valve on a cold-water line and attach a 3/4" BSP male fitting, (e.g., 3/4" x 1/2" 311
or washing machine type stop valve).
•For US versions use 9/16”-24 UNEF –male fitting.
•Connect straight tailpiece of the hose to the stop valve fitting. Make sure that the pre-
attached sealing washer is fitted.
•Turn on the water to flush any impurities, dust etc. from the inlet hose and water pipe. Allow
several litres through.
•Connect the hose to the inlet valve of the boiler (3/4" BSP). Make sure the sealing washer is
fitted.
•Turn on water and check for leaks.

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4.1 MT Boiler Installation (cont.)

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4.2 Filter Installation
Machine P/N: (1000763F#)

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5. BOILER SETUP
5.1 Operating Boiler for the First Time
•Check that all installation procedures have been carried out.
•Ensure water valve is connected and turned on.
•Plug in the IEC connector to the boiler.
•On models with a filter, connect the filter.
•Plug boiler into suitable socket.
•The boiler will power up.
•The screen will show the software revision.
•The machine will then fill with water and the display will flash between E-2 & the current
temperature of the tank, until the water has reached the low-level probe, then it will show the
current water temperature.
•The default temperature is 95°C (203°F).
•Once the machine is up to temperature the boiler is now ready for use.
NOTE:
Because the boiler is electronically controlled no priming is necessary.
The element cannot switch on until a safe level of water is reached.

1000762#, 763#, 764#, 765#, 766#, 1762#, 1763# Service Manual for REVIEW
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6. OVERVIEW & OPERATION
6.1 MT Boiler Operation

1000762#, 763#, 764#, 765#, 766#, 1762#, 1763# Service Manual for REVIEW
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6.2 MT Dual Tap Boiler Operation
Machine P/N: (1000764#)

1000762#, 763#, 764#, 765#, 766#, 1762#, 1763# Service Manual for REVIEW
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6.2 MT Dual Tap Boiler Operation (cont.)

1000762#, 763#, 764#, 765#, 766#, 1762#, 1763# Service Manual for REVIEW
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7. SERVICE SET UP
7.1 Changing Temperature

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7.2 Filter Mode
Machine P/N: (1000763F#)

1000762#, 763#, 764#, 765#, 766#, 1762#, 1763# Service Manual for REVIEW
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7.3 Changing from Celsius to Fahrenheit

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7.4 Heat Fill Selection

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7.5 Power Selection.

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8. ROUTINE MAINTAINENCE/INTERNAL ACCESS
Maintenance should be carried out by Marco approved technicians only.
8.1 Top Lid Removal
1. Remove the screws in the top lid with a suitable cross headed screwdriver.
2. Push Top Lid backwards and lift it up.
8.2 Lower Front Panel Removal
1. Put the Drip Tray aside.
2. Remove the screw in the lower front panel with a suitable cross headed screwdriver.
3. Push lower front panel downwards and pull it out from the machine.
i.
ii.
ii.
i.

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8.3 Draining the tank
1. Turn off machine and disconnect from mains power.
2. Allow to cool sufficiently to avoid burn risk.
3. Place machine so that the tap of the machine is located next to a sink or a bucket large enough
to hold the full contents of the tank.
4. Open the tap and drain the machine up to the spigot level.
5. Tilt the machine forward and drain the remain water.
8.4 PCB replacement
1. Turn off machine and disconnect from mains power.
2. Remove Top Lid as per sections 8.1.
3. Pull Plastic Front Panel upwards and tilt it forward.
4. Remove the PCB insulation block by cutting the cable tie.
5. Disconnect all wiring connected to the PCB and remove Plastic Front Panel from the machine.
6. Remove 3 nuts to release PCB from Plastic Front Panel.
i.
ii.

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8.5 Dispense Tap removal
To remove the dispense tap in any Tap version boiler: (CAUTION - make sure tank is drained fully
first as per section 8.3!)
1. Loosen Tap retaining nut by turning clockwise.
2. When tightening the nut, the tap should be gripped and held in place.
8.6 Heater Element Removal
1. Turn off machine and disconnect from mains power.
2. Drain the tank as per section 8.3.
3. Remove Top Lid, Plastic Front Panel & Lower Front Panel as per sections 8.1, 8.2 and 8.4.
4. Undo the four 6mm lock nuts and remove Inner Lid.
5. Disconnect all wiring connected to the Heater Element.
6. Undo the two 18mm lock nuts and slide the heater element tabs through the holes in the Tank
Body.
Please note the orientation of the heater element tabs which should face upwards.
CAUTION - the next steps applies to the 1000762# and 1001762# models only.
Tap retaining nut

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8.6 Heater Element Removal (cont.)
7. Rotate the heater element upwards up to the stage when it will go above the Thermistor Pocket.
8. Rotate it to the vertical position.
9. Rotate it to the stage when it will be possible to pull it out from the tank.
6.
7.
8.
9.