Cornelius NITROPRO MINI User manual

SPECIALTY BEVERAGE DISPENSER
NITROPRO MINI
Service and Preventative Maintenance Manual
Release Date: 2/15/19
Publication Number: 548000106SER
Revision Date: 2/15/19
Revision: Rev. 2.0 Model: CNB Mini
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The products, technical information, and instructions contained in this manual are subject to change without notice. These
instructions are not intended to cover all details or variations of the equipment, nor to provide for every possible contingency
in the installation, operation or maintenance of this equipment. This manual assumes that the person(s) working on the equip‐
ment have been trained and are skilled in working with electrical, plumbing, pneumatic, and mechanical equipment. It is
assumed that appropriate safety precautions are taken and that all local safety and construction requirements are being met,
in addition to the information contained in this manual.
This Product is warranted only as provided in Cornelius’ Commercial Warranty applicable to this Product and is subject to all of
the restrictions and limitations contained in the Commercial Warranty.
Cornelius will not be responsible for any repair, replacement or other service required by or loss or damage resulting from any
of the following occurrences, including but not limited to, (1) other than normal and proper use and normal service conditions
with respect to the Product, (2) improper voltage, (3) inadequate wiring, (4) abuse, (5) accident, (6) alteration, (7) misuse, (8)
neglect, (9) unauthorized repair or the failure to utilize suitably qualified and trained persons to perform service and/or repair
of the Product, (10) improper cleaning, (11) failure to follow installation, operating, cleaning or maintenance instructions, (12)
use of “non‐authorized” parts (i.e., parts that are not 100% compatible with the Product) which use voids the entire warranty,
(13) Product parts in contact with water or the product dispensed which are adversely impacted by changes in liquid scale or
chemical composition.
Contact Information:
To inquire about current revisions of this and other documentation or for assistance with any Cornelius product contact:
www.cornelius.com
800-238-3600
Trademarks and Copyrights:
This document contains proprietary information and it may not be reproduced in any way without permission from Cornelius.
This document contains the original instructions for the unit described.
CORNELIUS INC
101 Regency Drive
Glendale Heights, IL
Tel: + 1 800‐238‐3600
Printed in U.S.A.
Correct Disposal of this Product
RECYCLE
This marking indicates that this product should not be disposed with other household wastes throughout the EU. To prevent
possible harm to the environment or human health from uncontrolled waste disposal, recycle it responsibly to promote the
sustainable reuse of material resources. To return your used device, please use the return and collection systems or contact
the retailer where the product was purchased. They can take this product for environmental safe recycling.

1.0 SAFETY 1
2.0 OVERVIEW AND REQUIRED TOOLS 3
2.1 Nitropro Functions & Specifications 3
2.2 Key Components 4
2.3 Required Tools 6
3.0 SYSTEM OPERATION 7
3.1 Facility Supplies 7
3.2 Operating Processes 8
3.3 Component Functions
3.3.1 Tap Handles 10
3.3.2 Product Concentrate Pump 10
3.3.3 Water Inlet Solenoid 11
3.3.4 Air Compressor & Storage 11
3.3.5 Mixing-Infusion Manifold & Check Valves 11
3.3.6 Dispense Manifold 12
3.3.8 Mixing-Dispensing Assembly 12
3.3.9 Ice Bank Chilling System 13
3.3.10 Front-Door Control Switches 14
4.0 PREVENTATIVE MAINTENANCE 15
4.1 Overview 15
4.2 Maintenance Schedule 15
4.3 Annual Maintenance 15
4.3.1 Refrigeration Condenser & Cabinet Fan Cleaning 15
4.3.2 Ice Bank Level Check 15
4.3.3 Product Pump Mix-Ratio Verification 16
4.3.3.1 Measuring TDS (Total Dissolved Solids) 16
4.3.4 Components Visual Inspection 18
4.3.5 Ice-Bank Sensor & Agitator Check 18
4.3.6 Concentrate-Pump Hose Replacement 19
Table of Contents

5.0 TROUBLESHOOTING 20
Table 5-1 - Systems-Level Troubleshooting 20
Table 5-2 - Drink-Quality Troubleshooting 21
Table 5-3 - Compressed Air & Infusion Troubleshooting 22
Table 5-4 - Dispensing-Function Troubleshooting 23
5.1 Air-Compressor Pressure Verification 24
6.0 COMPONENT REPLACEMENT 25
6.1 Safety Precautions 25
6.3 Access Panel Removal 25
6.3 Main PCB 27
6.4 Mixing-Dispensing Assembly Components 28
6.4.1 Air Pressure Regulator 28
6.4.2 Mixing - Infusion Manifold 29
6.4.3 Dispense Manifold 29
6.4.4 Concentrate Pump 30
6.5 Air Compressor 30
6.5.1 Compressor Air Filter Replacement 30
6.6 Water Inlet Solenoid 31
6.7 Power Supply (24Vdc) 31
6.8 Merchandiser LED Back-Lighting Panel 32
6.9 Ice Bank 32
6.9.1 Ice Sensor Probe 32
6.9.2 Agitator Motor 33
6.9.3 Ice Bank Controller 34
6.9.4 Refrigeration Components 35
6.10 Tap Microswitches 35
APPENDIX A - SYSTEM DRAWINGS 37
Table of Contents

Nitropro Mini Service Manual
© 2019, Cornelius Inc. All Rights Reserved - 1 - Publication Number: 548000106SER
1.0 SAFETY INSTRUCTIONS
Safety Overview
• Read and follow ALL SAFETY INSTRUCTIONS in this manual and any warning/caution labels on the
unit (decals, labels or laminated cards).
• Read and understand ALL applicable OSHA (Occupational Safety and Health Administration) safety
regulations before operating this unit.
Types of Alerts
!
!
DANGER: Indicates an immediate hazardous situation which if not avoided WILL result in
serious injury, death or equipment damage.
!
!
WARNING: Indicates a potentially hazardous situation which, if not avoided, COULD result in
serious injury, death, or equipment damage.
!
!
CAUTION: Indicates a potentially hazardous situation which, if not avoided, MAY result in
minor or moderate injury or equipment damage.
SAFETY TIPS
• Carefully read and follow all safety messages in this manual and safety labels on the unit.
• Keep safety labels in good condition and replace missing or damaged ones.
• Do not let anyone operate the unit without proper training. This appliance is not intended for use
by untrained or unauthorized persons without supervision.
• Maintain the unit in proper working condition and do not allow any unauthorized modifications.
NOTE: The dispenser is not designed for a wash-down environment and MUST NOT be placed in
an area where a water jet could be used.
QUALIFIED SERVICE PERSONNEL

WARNING:
Only trained and certified electrical, plumbing and refrigeration technicians should service this unit.
ALL WIRING AND PLUMBING MUST CONFORM TO NATIONAL AND LOCAL CODES. FAILURE TO COMPLY-
COULD RESULT IN SERIOUS INJURY, DEATH OR EQUIPMENT DAMAGE. IF THE SUPPLY CORD IS DAMAGED,
IT MUST BE REPLACED BY THE MANUFACTURER, ITS SERVICE AGENT OR SIMILARLY QUALIFIED PERSONS
IN ORDER TO AVOID A HAZARD.
!

Nitropro Mini Service Manual
Publication Number: 548000106SER - 2 - © 2019, Cornelius Inc. All Rights Reserved
1.0 SAFETY INSTRUCTIONS (CONT.)
SAFETY PRECAUTIONS
This unit has been specifically designed to provide protection against personal injury. To ensure contin-
ued protection observe the following:

DANGER:
Disconnect power to the unit before servicing while following all lock out/tag out procedures estab-
lished by the user. Verify power is off to the unit before any work is performed.
FAILURE TO DISCONNECT THE POWER COULD RESULT IN SERIOUS INJURY, DEATH OR EQUIPMENT
DAMAGE.

CAUTION:
Always be sure to keep area around the unit clean and free of clutter. Failure to keep this area clean may
result in injury or equipment damage.
DO NOT STORE EXPLOSIVE SUBSTANCES SUCH AS AEROSOL CANS WITH A FLAMMABLE PROPELLANT IN
THIS APPLIANCE.
UNTRAINED AND UNAUTHORIZED INDIVIDUALS SHALL NOT OPERATE THE APPLIANCE OR PERFORM 
ANY CLEANING OR USER-MAINTENANCE PROCEDURES.
SHIPPING AND STORAGE

CAUTION:
Before shipping, storing, or relocating the unit, the unit must be sanitized and all sanitizing solution
must be drained from the system. A freezing ambient environment will cause residual sanitizing solution
or water remaining inside the unit to freeze resulting in damage to internal components.
MOUNTING IN OR ON A COUNTER

DANGER:
When installing the unit in or on a counter top, the counter must be able to support a weight in excess of
140 lbs. (63.5 kg.) to insure adequate support for the unit.
FAILURE TO COMPLY COULD RESULT IN SERIOUS INJURY, DEATH OR EQUIPMENT DAMAGE.
THE APPLIANCE MUST BE ORIENTED IN A VERTICAL POSITION.
!
!
!
!

Nitropro Mini Service Manual
© 2019, Cornelius Inc. All Rights Reserved - 3 - Publication Number: 548000106SER
2.0 OVERVIEW AND REQUIRED TOOLS
2.1 Nitropro Functions & Specifications
The Nitropro Mini dispenses still or air-injected,
chilled Nitro coffee at the pull of a tap handle.
Opening a tap automatically engages the product
mixing pump (as well as the air pump for the
injected-coffee selection). The dispensing unit
requires facility electrical and water inputs; Nitro
infusion gas is generated within the unit.
• Coffee syrup from a product container is auto-
matically mixed with water at the selected
ratio (with mix ratios user-selectable via a DIP
switch on the main control PCB)
• Nitro coffee is created via its dispensing circuit
including a gas-infusion (air-injection) mani-
fold prior to the tap (dispensing) valve
• Metering of the product concentrate is per-
formed by a servo-driven, peristaltic pump
• Water inlet rate is fixed and controlled by an
inlet solenoid valve assembly that also pro-
vides pressure limiting and flow control
• Chilling of the product cabinet and mix water
is performed by an automatically-controlled
ice bank at the base of the enclosure
Table 2-1 - Electrical Specifications
Models VAC Amps Ph Hz
CNB
Mini 115 5 1 60
CNB
Mini 230 2 1 50
Table 2-2 - Refrigerant Type
Refrigerant
Oz Grams Type
5.64 160 R-134a
Table 2-3 - Refrigeration Nameplate Values
Pressure psi (kPa) [ bar]
High
side Low side
315 (2171.9) [21.7 ] 140 (965.3) [9.7]
Table 2-4 - Water Requirements
Water Supply Pressure
35 psig (241 kPa) Min.
90 psig (621 kPa) Max.
(if >90 psi, install external pres-
sure regulator, set @ 50 psi)
Water Supply
Flow Rate
3 fl. oz. (88.7 ml) per
second, minimum
Water Temperature 40 - 90° F. (4.4 - 32.2° C)
Water Inlet Size 3/8 in. (0.95 cm) SAE male flare
fitting on dispenser
Table 2-5 - General | Dimensions | Weight
Unit Height 34.05 in. (86.5 cm)
Unit Width 10.44 in. (26.5 cm)
Unit Depth 24.47 in. (62.2 cm)
Clearance
Requirements
Back: 4” (10.16 cm)
Top: 12” (30.48 cm)
Sides: 4” (10.16 cm)
Unit Weight (Dry) 120 lbs (54.4 kg)
Operating Weight 185 lbs (84.0 kg)
Ambient Operating
Temperature 50 to 90 °F (10 to 32 °C)
Table 2-6 - Ice Bank Specifications
Ice Bank Capacity 7-8 lbs. (3.2-3.6 kg.)
Temp. Pull Down Time 3 hours at 75 °F (24 °C)

Nitropro Mini Service Manual
Publication Number: 548000106SER - 4 - © 2019, Cornelius Inc. All Rights Reserved
2.0 BREWER OVERVIEW AND REQUIRED TOOLS (Cont.)
2.2 Key Components
The Nitropro Mini consists of these main controls
and components (refer to Figs. 2-1 and 2.2).
Dispensing Taps (for Still & Nitro Coffee)
Allow coffee dispensing. Pulling of tap
handle triggers switch that activates outlet
solenoid valve (in dispense manifold); also
turns on water inlet solenoid valve and
concentrate pump to initiate flow.
Ice Bank (Water Reservoir and Refrig. Unit)
Water/ice-filled reservoir for chiller lines.
Includes controller to manage refrigeration
compressor, bath agitator, circulation pump
and temperature/ice sensor.
Air Compressor & Storage Chamber
Provides air to the gas-infusion manifold.
Stores compressed air to support high drink
volumes. The compressor is independent
and is activated by the storage-chamber
pressure switch. Storage outlet routes to a
pressure regulator prior to entering the
infusion manifold.
Concentrate Pump
Meters input of coffee product from BIB
(Bag In Box) to mixing manifold. Peristaltic
pump, servo-motor driven.
Product-Mixing & Gas-Infusion Manifold
Interconnected plastic blocks with check
valves and a mixing chamber for mixing, air-
injecting and routing of coffee concentrate,
water and air to the dispense manifolds.
Three check valves control flow routing by
preventing backflow.
Dispense Manifolds
Tap-handle activated, outlet solenoid valve.
Outlet valve allows product dispensing.
Water-Inlet Solenoid Valve/Regulator
Solenoid valve allows water inlet.
Regulator limits inlet pressure & flow rate.
System Controller Board (Main PCB)
Manages system events and device
interactions. Includes adjustable DIP switch
for concentrate-pump ratio selection. Also
includes PCB switches for fine-tuning the
ratio selection.
24Vdc Power Supply
Provides power to Main PCB and the air
compressor.
Figure 2-1 - Front LED-Backed Merchandiser Removal

Nitropro Mini Service Manual
© 2019, Cornelius Inc. All Rights Reserved - 5 - Publication Number: 548000106SER
2.0 BREWER OVERVIEW AND REQUIRED TOOLS (Cont.)
2.2 Key Components (Cont.)
Figure 2-2 - Main Components

Nitropro Mini Service Manual
Publication Number: 548000106SER - 6 - © 2019, Cornelius Inc. All Rights Reserved
2.0 BREWER OVERVIEW AND REQUIRED TOOLS (Cont.)
2.3 Required Tools
These tools are required for conducting the vari-
ous procedures in this manual. You may find it
helpful to review the Troubleshooting and Com-
ponent Replacement sections to determine what
additional tools you might prefer to include.
HAND TOOLS
Wrenches - SAE Open-end or Combination
(1/4” through 7/8”)
Wrenches - Adjustable
(2” x 6”- 8” Length, Crescent)
Nut Driver Set - SAE
Pliers - Adjustable
Channel-Lock/Knipex-style
Pliers - Needlenose
Flat Screwdriver
3/16”
Phillips Screwdrivers
#2 & #0 (6” Length)
#2 Stubby or Flex-shaft
Diagonal Cutting Pliers
Pick Set - Dental Type
Magnetic Pickup Wand
Cleaning Brushes
Bristle and Wire
Air Pressure Gauge
Capable of 100 psi (689 kPa)
with high-pressure hose and
1/4”push-connect fitting
Hose-Clamp Crimping/Cutting Tool
Oetiker HIP 2800 Es
ELECTRICAL TOOLS
Multimeter - Digital VOM
1000V/10A ac/dc, milliohm to megohm, millivolt,
auto-ranging, ±2.5% +1 digit accuracy
Temperature Meter & Probe
±2.5% +1 digit accuracy
Cordless Drill or Screwdriver
With Screwdriver Bits / Nut Drivers
Flashlight
Portable Vacuum Cleaner
With hose and crevice tool
SUPPLIES
O-Ring Lubricant/Sealant Food-Grade Silicone
Dow Corning Molykote 111 or equiv.
Solvent - Nonflammable
Teflon Thread-sealing Tape
Lint-free Cloth Rags

Nitropro Mini Service Manual
© 2019, Cornelius Inc. All Rights Reserved - 7 - Publication Number: 548000106SER
3.0 SYSTEM OPERATION
This section describes how the Nitropro Mini dis-
penser operates. By grasping the details of the
operating process for still and Nitro coffee dis-
pensing, you will have the knowledge to detect
many of the common malfunctions.
3.1 Facility Supplies
Electrical: Depending on model and application,
the unit operates from either 115Vac or 230Vac
that enters the unit through a back-panel cord
socket, as shown in Fig 3-1. Input AC power is sup-
plied to the ice bank controller (which manages
the refrigeration compressor and the ice-bath agi-
tator motor). AC power is also routed to the
24Vdc power supply which provides power to the
Main PCB and the air pump. The Main PCB then
provides 24V power to the remainder of the DC
components.
Water: Store water enters the unit through a rear
inlet solenoid valve within the pressure range
indicated in Figure 3-2. The inlet solenoid valve
activates when a dispensing tap is pulled. The
inlet solenoid assembly also provides input pres-
sure control [29 psi (200 kPa) - fixed] and flow-rate
limiting within the range of 1 to 1.25 fluid ounces
(29.6 to 37 ml) per second.
Inlet water is first routed to the ice bank for chill-
ing and then is supplied to the mixing-infusion
manifold.
Figure 3-1 - Power Input
Figure 3-2 - Water Input

Nitropro Mini Service Manual
Publication Number: 548000106SER - 8 - © 2019, Cornelius Inc. All Rights Reserved
3.0 SYSTEM OPERATION (Cont.)
3.2 Operating Processes
1Left Tap Handle - Still Coffee Dispensing
Figure 3-3 - Still Coffee Dispense Process
Step 1) Left tap handle is pulled.
Step 2) Left Dispense switch is depressed, activating (via Main PCB):
Dispense Manifold Solenoid Valve (allows front dispensing)
Concentrate Pump (delivers coffee concentrate to Mixing Manifold)
Inlet Solenoid (delivers water to Mixing Manifold)
Action: Water and coffee concentrate combine in the mixing manifold and then flow to
the dispense manifold and into the serving cup. NOTE: There is no flow in the Nitro-cof-
fee circuit and infusion manifold since its dispense valve is closed. The low-pressure path
is to the still-coffee dispense manifold in which the dispense solenoid valve is open.

Nitropro Mini Service Manual
© 2019, Cornelius Inc. All Rights Reserved - 9 - Publication Number: 548000106SER
3.0 SYSTEM OPERATION (Cont.)
3.2 Operating Processes (Cont.)
2Right Tap Handle - Nitro Coffee DispensingRight Tap Handle - Nitro Coffee Dispensing
Figure 3-4 - Nitro Coffee Dispense Process
Step 1) Right tap handle is pulled.
Step 2) Right Dispense switch is depressed, activating (via Main PCB):
Dispense Manifold Solenoid Valve (allows front dispensing)
Concentrate Pump (delivers coffee concentrate to Mixing Manifold)
Inlet Solenoid (delivers water to Mixing Manifold)
Action: Water and coffee concentrate combine in the mixing manifold, are then infused
with air in the gas infusion manifold and then flow to the Nitro dispense manifold and
into the serving cup. NOTE: There is no flow in the still-coffee circuit since its dispense
valve is closed. The low-pressure path is to the Nitro-coffee dispense manifold in which
the dispense solenoid valve is open.

Nitropro Mini Service Manual
Publication Number: 548000106SER - 10 - © 2019, Cornelius Inc. All Rights Reserved
3.0 SYSTEM OPERATION (Cont.)
3.3 Component Functions
3.3.1 Tap Handles
The dispensing tap handles (Fig.3-5), when pulled,
activate microswitches (Fig. 3-6) that signal the
Main PCB to activate specific components, as de-
scribed previously in section 3.2.
3.3.2 Coffee Concentrate Pump
This pump (Fig.3-7) draws coffee concentrate
from the chilled Bag In Box (BIB) and meters it to
the mixing manifold at a specific, user-selected
ratio to the input water (which is supplied at a
fixed pressure and flow rate).
Mixing ratios are adjusted by changing the DIP
switch settings on the Main PCB mounted
beneath the cabinet, as shown in Figure 3-8.
Adjustment of these settings changes the speed
of the peristaltic pump to provide more or less
concentrate per unit time.
The selectable ratios provide, from one gallon of
concentrate, the coffee yields shown in Table
3-1. (NOTE: Select one ratio - one switch ON.)
Ratio Tuning Buttons: One press of a button
changes the pump motor speed by 5 RPMs (or by
0.02 - 0.08 of the average TDS value).
The peristaltic pump is driven by a 24V DC servo
motor. A maintenance kit for the pump includes a
replacement pump hose with nipple ends.
Figure 3-5 - Tap Handles / Microswitch Assemblies
Figure 3-6 - Microswitch Assembly
Table 3-1 - Concentrate Pump Ratios
Ratio Main PCB
Switch Setting
Concentrate
Gallons
Coffee Yield
Gallons
3:1 Switch 1 ON 1 4
4:1 Switch 2 ON 1 5
5:1 Switch 3 ON 1 6
7:1 Switch 4 ON 1 8
Figure 3-7 - Concentrate Pump
Figure 3-8 - Ratio Select Switch & Tuning Buttons

Nitropro Mini Service Manual
© 2019, Cornelius Inc. All Rights Reserved - 11 - Publication Number: 548000106SER
3.0 SYSTEM OPERATION (Cont.)
3.3 Component Functions (Cont.)
3.3.3 Water Inlet Solenoid
This device controls the water input to the mixing
manifold. It also limits input pressure to 29 psi
(200 kPa) and limits the water flow rate within the
range of 1 to 1.25 fluid ounces (29.6 to 37 ml) per
second.
3.3.4 Air Compressor & Storage
The 24Vdc air compressor provides air to the mix-
ing-infusion manifold to produce Nitro coffee. It
operates independently so that stored air is
always available when the Nitro-coffee tap is acti-
vated. The pressure switch stops compressor
operation when a storage-chamber pressure of 80
psi (552 kPa) is detected. The pressure-relief valve
activates at 95 psi (655 kPa) in the event of
pump-motor runaway.
3.3.5 Mixing-Infusion Manifold & Check Valves
The mixing manifold has two halves and is con-
nected to the air-infusion manifold. Three check
valves prevent reverse flow in the supply lines and
chambers. The assembled check valves snap into
place in the manifold.
.
Figure 3-9 - Water Inlet Solenoid
Figure 3-10 - Air Compressor and Air Storage
Figure 3-11 - Mixing-Infusion Manifold & Check Valves

Nitropro Mini Service Manual
Publication Number: 548000106SER - 12 - © 2019, Cornelius Inc. All Rights Reserved
3.0 SYSTEM OPERATION (Cont.)
3.3 Component Functions (Cont.)
3.3.6 Dispense Manifold
There is a dispense manifold for each coffee type.
It receives the mixed coffee and dispenses it
through a solenoid valve that is electrically acti-
vated by the tap handle. During operation (when
open) the solenoid plunger, to which a valve seat
is attached, retracts to allow flow through the
valve orifice (Fig. 3-12).
3.3.7 Power Supply (24Vdc)
This unit provides DC power for the air compres-
sor and the Main PCB.
3.3.8 Mixing-Dispensing Assembly
This removable assembly performs the mixing,
air-injection and dispensing functions of the unit.
It consists of the components identified in Figure
3-14. The air-pressure regulator allows user
adjustment of the air-infusion pressure for Nitro
coffee. The assembly is mounted in the chilled
cabinet.
Figure 3-12 - Dispense Manifold Assembly
Figure 3-13 - 24Vdc Power Supply
Figure 3-14 - Mixing-Dispensing Assembly

Nitropro Mini Service Manual
© 2019, Cornelius Inc. All Rights Reserved - 13 - Publication Number: 548000106SER
3.0 SYSTEM OPERATION (Cont.)
3.3 Component Functions (Cont.)
3.3.9 Ice Bank Chilling System
In the base of the unit resides the insulated ice
bank assembly. It is comprised of a refrigeration
unit (in the rear of the enclosure), a water/ice res-
ervoir, an agitator/circulation pump to control ice
formation and circulate cooling water, an ice sen-
sor and a control module, The control module
manages the refrigeration system and the agitator
based on feedback from the ice sensor. Water
from the inlet solenoid is routed through a stain-
less steel coil in the ice bank for chilling. As well,
cooling lines from the circulation pump are routed
into the product cabinet where a fan circulates
chilled air.
Figure 3-15 - Ice Bank and Controller Module
Figure 3-16 - Ice Bank Sensor & Agitator Motor

Nitropro Mini Service Manual
Publication Number: 548000106SER - 14 - © 2019, Cornelius Inc. All Rights Reserved
3.0 SYSTEM OPERATION (Cont.)
3.3 Component Functions (Cont.)
3.3.10 Front-Door Control Switches
These two switches control the merchandiser LED
backlight on the front of the door and the dis-
pensing circuit, as indicated below.
Door Light: On/Off switch turns LED backlight on
or off.
Dispense Motor: A 3-position switch for normal
operation (ON), system shutoff (OFF) and for per-
forming sanitizing procedures (CLEAN). In CLEAN
mode, this switch sets the concentrate pump to
the water/cleaning-agent mixing ratio (5:1). When
the switch is returned to the ON position, the mix-
ing ratio returns to that selected on the pump
mix-ratio switch bank (Fig. 3-8).
Figure 3-17 - Front Door Switches

Nitropro Mini Service Manual
© 2019, Cornelius Inc. All Rights Reserved - 15 - Publication Number: 548000106SER
4.0 PREVENTATIVE MAINTENANCE
4.1 Overview
Perform the procedures in this section at the
intervals indicated to ensure consistent, safe and
clean operation of the unit. These are provided in
addition to the routine cleaning and sanitizing
procedures included in the Installation & Opera-
tion manual.
4.2 Maintenance Schedule
4.3 Annual Maintenance
4.3.1 Refrigeration Condenser & Cabinet Fan
Cleaning
To ensure optimal cooling efficiency, clean the fan
blades and grilles of any collected dust and debris.
(The use of compressed or canned air to clean the
refrigeration condenser fan blades is adequate.)
4.3.2 Ice Bank Level Check
The water level in the ice bank may require peri-
odic topping off to ensure optimal operation.
Check and refill it as indicated below.
The fill tube is located behind the front splash
panel and is capped with a red plug.
The small, black, overflow tube, connected to an
internal standpipe, will emit water during manual
refill when the water level reaches the full mark.
NOTE: When the fill tube is in its stored posi-
tion (as shown in Fig. 4-2) it also serves as a
‘sight glass’ indicating the bank water level.
1) Remove the drip tray and splash panel to reveal
the front of the ice bank.
2) Observe the fill tube and the water level in it. If
the water level is below the top of the tube arc,
add water to the ice bank.
3) Add filtered store water through the fill tube
after extending it from its storage position and
removing the red cap. Add water until a trickle
runs out of the black overflow tube.
4) Cap the fill tube and return it to its storage
position.
Table 4-1 - Maintenance Schedule
Procedure Section Interval
(Months)
Refrig. condenser & cabinet fan cleaning 4.3.1 12
Ice bank level check 4.3.2 12
Concentrate pump mix ratio verification 4.3.3 12
Components visual inspection 4.3.4 12
Concentrate-pump hose replacement 4.3.5 12
Figure 4-1 - Fans
Figure 4-2 - Ice Bank Fill & Overflow Tubes

Nitropro Mini Service Manual
Publication Number: 548000106SER - 16 - © 2019, Cornelius Inc. All Rights Reserved
4.0 PREVENTATIVE MAINTENANCE (Cont.)
4.3.3 Product Pump Mix-Ratio Verification
It is important to ensure consistency in the dis-
pensed coffee, thus the coffee-concentrate/water
mixing ratios must be verified. Since the ratios are
selected via the Main PCB DIP switch setting, and
may sometimes require adjustment using the tun-
ing buttons, a routine check of the ratios is essen-
tial. Follow the applicable procedure below to
verify/adjust each of the four mixing ratios.
1) Set the DIP switch for a ratio (Fig. 4-3).
2) Prior to installing, shake the concentrate BIB.
NOTE: If concentrate is not properly thawed, it
will adversely affect the amount of concentrate
dispensed. Thawed concentrate should be
between 35 °F (1.6 °C) to 40 °F (4.4 °C) and
have no ice particles remaining in it.
3) Dispense approximately 16 oz. of drink and dis-
card. This is done to purge any water or coffee
dispensed using the previous settings.
4) Draw an 8 oz. drink into a clean dry cup, and
measure the temperature to confirm the drink
is between 35 to 45°F.
NOTE: Drink temperature must be maintained
to properly set the ratio of the unit.
5) Stir the sample thoroughly, and measure the
TDS of the drink (refer to the TDS measuring
procedures in section 4.3.3.1).
6) If the TDS matches the desired range of the
product, no further adjustments are necessary.
If the TDS is above/below required value, use
the ‘UP’ or ‘DOWN’ Ratio Tuning buttons as
necessary to achieve the desired value. (One
press of a tuning button changes the pump
motor speed by 5 RPMs; or by 0.02 - 0.08 of
the average TDS value.
NOTE: Dispense a 16 oz. drink to purge the pre-
vious setting before measuring again.
NOTE: Make adjustments in 1-2 button pushes
to avoid overshooting the target value.
7) Once the desired value is reached, the setup is
complete and should be stable with standard
maintenance of the equipment.
8) Perform the previous steps for the remaining
three ratios to verify/adjust them.
NOTE: The adjusted ratio settings will not be
reset by Clean mode or power loss.
NOTE: If a coffee concentrate flavor, manufac-
turer or ratio type is changed, repeat this pro-
cess to set the ratio accurately. Conducting this
process is not necessary when changing BIBs of
the same type of coffee concentrate.
4.3.3.1 Measuring TDS (Total Dissolved Solids)
There are three methods that may be used to
check/calibrate the ratio setting of the equip-
ment.
1. Using a TDS Meter
2. Using a Brix Meter/Refractometer
3. Manually Checking Volume Ratio
For each method, access the mix-ratio control
switches (Fig. 4-3) by removing the splash panel.
NOTE: Only one ratio select switch is allowed to
be On, with all others Off.
Table 4-2 - Mix Ratio Main PCB Switch Settings
Ratio Main PCB
Switch Setting
Concentrate
Gallons
Coffee Yield
Gallons
3:1 Switch 1 ON 1 4
4:1 Switch 2 ON 1 5
5:1 Switch 3 ON 1 6
7:1 Switch 4 ON 1 8
Figure 4-3 - Ratio Select Switch & Tuning Buttons