Hoshizaki RM-7-HC User manual

Service Manual
hoshizakiamerica.com
Refrigerator R-290
Model
RM-7-HC
RM-10-HC
RM-26-HC
RM-45-SD-HC
RM-49-HC
RM-65-HC
Number: MAN-243-R
Issued: 12-17-2018
Revised: 05-16-2019

2
WARNING
Only qualied service technicians should install and service the appliance. To
obtain the name and phone number of your local Hoshizaki Certied Service
Representative, visit www.hoshizaki.com. No service should be undertaken until
the technician has thoroughly read this Service Manual. Failure to service and
maintain the appliance in accordance with this manual will adversely affect safety,
performance, component life, and warranty coverage. Proper installation is the
responsibility of the installer. Product failure or property damage due to improper
installation is not covered under warranty.
Hoshizaki provides this manual primarily to assist qualied service technicians in the
service of this appliance.
Should the reader have any questions or concerns which have not been satisfactorily
addressed, please call, send an e-mail message, or write to the Hoshizaki Technical
Support Department for assistance.
Phone: [phone]
Fax: [phone]
E-mail: [email protected]
618 Highway 74 South
Peachtree City, GA 30269
Attn: Hoshizaki Technical Support Department
Web Site: www.hoshizaki.com
NOTE: To expedite assistance, all correspondence/communication MUST include the
following information:
• Model Number
• Serial Number
• Complete and detailed explanation of the problem.

3
IMPORTANT
This manual should be read carefully before the appliance is serviced. Read
the warnings and guidelines contained in this booklet carefully as they provide
essential information for the continued safe use, service, and maintenance of the
appliance. Retain this booklet for any further reference that may be necessary.
Contents
Important Safety Information ................................................................................................. 4
I. General Information ............................................................................................................ 7
A. Construction.................................................................................................................. 7
B. Refrigeration Circuit....................................................................................................... 8
II. Sequence of Operation and Service Diagnosis................................................................. 9
A. Sequence Flow Chart ................................................................................................... 9
B. Service Diagnosis ....................................................................................................... 10
1. Troubleshooting ...................................................................................................... 12
C. Control Module Check................................................................................................. 15
D. Thermistor Check........................................................................................................ 16
E. Temperature Setting Dial............................................................................................. 17
III. Refrigeration Circuit and Component Service Information ............................................. 18
A. Service for Refrigerant Lines....................................................................................... 20
1. Refrigerant Recovery ............................................................................................. 21
2. Brazing .................................................................................................................. 21
3. Evacuation ............................................................................................................ 22
4. Recharge ............................................................................................................... 22
B. Maintenance................................................................................................................ 23
1.Condenser .............................................................................................................. 23
2.Power Supply Connection ...................................................................................... 23
IV. Preparing the Appliance for Periods of Non-Use ............................................................ 24
V. Disposal........................................................................................................................... 25
VI. Technical Information...................................................................................................... 26
A. Electrical and Refrigerant Data ................................................................................... 26
B. Wiring Diagram............................................................................................................ 27

4
Important Safety Information
Throughout this manual, notices appear to bring your attention to situations which could
result in death, serious injury, damage to the appliance, or damage to property.
DANGER Indicates a hazardous situation that, if not avoided, will result in
death or serious injury.
WARNING Indicates a hazardous situation that, if not avoided, could result
in death or serious injury.
NOTICE Indicates a situation that, if not avoided, could result in damage
to the appliance or property.
IMPORTANT Indicates important information about the use and care of the
appliance.
DANGER
Risk of Fire or Explosion
Flammable Refrigerant Used
• Follow handling instructions carefully
in compliance with U.S. government
regulations.
• Do not use mechanical devices to defrost.
• Do not puncture refrigerant tubing. Risk
of re or explosion due to puncture
of refrigerant tubing; follow handling
instructions carefully.
• Component parts shall be replaced with
like components.
• Servicing shall be done by factory
authorized service personnel to minimize
the risk of possible ignition due to incorrect
parts or improper service.
• Consult instruction manual/ service
manual before attempting to install or
service this product. All safety precautions
must be followed.
• Dispose of properly in accordance with
federal or local regulations.
• Do not place any potential ignition sources
in or near the appliance.
Risque De Feu Ou D'Explosion
Le Frigorigène Est Inammable
• Suivre attentivement les instructions
de manipulation conformément à la
réglementation gouvernementale.
• Ne pas utiliser d'appareils mécaniques
pour dégivrer le réfrigérateur.
• Ne pas perforer la tubulure contenant le
frigorigène. Risque de feu ou d'explosion
si la tubulure contenant le frigorigène
est perforée; suivre les instructions de
manutention avec soin.
• Les pièces des composants doivent être
remplacées par des pièces et accessoires
équivalents.
• L’entretien doit être effectué par le
personnel de service autorisé par le
fabricant an de minimiser les risques
d’inammation attribuables à l’installation
d’une pièce inadéquate ou à la mauvaise
exécution du service.
• Consulter le manuel du propriétaire/
guide de réparation avant de tenter une
réparation. Toutes les mesures de sécurité
doivent être respectées.
• Éliminer conformément aux règlements
fédéraux ou locaux.
• Ne placez aucune source d’inammation
potentielle dans ou près de l’appareil.

5
WARNING
This appliance should be destined only to the use for which it has been
expressly conceived. Any other use should be considered improper and
therefore dangerous. The manufacturer cannot be held responsible for injury
or damage resulting from improper, incorrect, and unreasonable use. Failure to
install, operate, and maintain the appliance in accordance with this manual will
adversely affect safety, performance, component life, and warranty coverage.
To reduce the risk of death, electric shock, serious injury, or re, follow
basic precautions including the following:
• Only qualied service technicians should install and service this appliance.
• Wear appropriate personal protective equipment (PPE) when servicing the
appliance.
• The appliance must be installed in accordance with applicable national,
state, and local codes and regulations.
• Appliance is heavy. Use care when lifting or positioning. Work in pairs when
needed to prevent injury or damage.
• The appliance requires an independent power supply of proper capacity.See
the nameplate for electrical specications. Failure to use an independent
power supply of proper capacity can result in a tripped breaker, blown fuse,
or damage to existing wiring. This could lead to heat generation or re.
• To reduce the risk of electric shock, do not touch the plug with damp hands.
• Unplug the appliance from the electrical outlet.
• THE APPLIANCE MUST BE GROUNDED:The appliance is equipped with a
NEMA 5-15 three-prong grounding plug to reduce the risk of potential shock
hazards. It must be plugged into a properly grounded, independent 3-prong
wall outlet. If the outlet is a 2-prong outlet, it is your personal responsibility to
have a qualied electrician replace it with a properly grounded, independent
3-prong wall outlet. Do not remove the ground prong from the plug and do
not use an adapter plug. Failure to follow these instructions may result in
death, electric shock, or re.
• The GREEN ground wire in the factory-installed power cord is connected to
the appliance. If it becomes necessary to remove or replace the power cord,
be sure to connect the power cord’s ground wire.
• Do not use an extension cord.
• Do not use an appliance with a damaged power cord.The power cord should
not be altered, jerked, bundled, weighed down, pinched, or tangled. Such
actions could result in electric shock or re.To unplug the appliance, be sure
to pull the plug, not the cord, and do not jerk the cord.
• Do not splash, pour, or spray water directly onto or into the appliance. This
might cause short circuit, electric shock, corrosion, or failure.
• Do not make any alterations to the appliance. Alterations could result in
electric shock, injury, re, or damage to the appliance.

6
WARNING, continued
• The appliance 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 appliance by a person responsible for their safety.
• Children should be properly supervised around the appliance.
• Do not climb, stand, or hang on the appliance or door or allow children
or animals to do so. Do not climb into the appliance or allow children or
animals to do so. Death or serious injury could occur or the appliance could
be damaged.
• Be careful not to pinch ngers when opening and closing the door.Be careful
when opening and closing the door when children are in the area.
• Open and close the doors with care. Doors opened too quickly or forcefully
may cause injury or damage to the appliance or surrounding equipment.
• Do not use combustible spray or place volatile or ammable substances
near the appliance. They might catch re.
• Keep the area around the appliance clean. Dirt, dust, or insects in the
appliance could cause harm to individuals or damage to the appliance.
• Do not place anything on top of the appliance. Foreign objects or moisture
could enter the appliance and result in electric shock or re.
• Do not block air inlets or outlets, otherwise cooling performance may be
reduced.
• Do not tightly pack the cabinet. Allow some space between items to ensure
good air ow. Also allow space between items and interior surfaces.
• Do not store items near the air outlet. They might freeze up and crack or
break causing a risk of injury or contamination of other food.
NOTICE
• Protect the oor when moving the appliance to prevent damage to the oor.
• Keep ventilation openings, in the appliance enclosure or in the built-in
structure, clear of obstruction. Do not place anything on top of the appliance.
Blockage of airow could negatively affect performance and damage the
appliance.
• To prevent deformation or cracks, do not spray insecticide onto the plastic
parts or let them come into contact with oil.
• To avoid damage to the gasket, use only the door handle when opening and
closing.

7
I. General Information
A. Construction
Forced-air evaporator for quick
temperature pull down
Interior lighting LED lamp
strip
NSF compliant interior
cabinet
Strong body with 1 3/4”
thick walls, injected with
polyurethane foam
using cyclopentane as
the blowing agent earth friendly
Heavy duty R-290
condensing unit with
easy access for
maintenance
Condenser
Heavy duty hinges
Reinforced, 16 gauge,
galvanized steel base
Illuminated sign
Exterior cabinet made of
galvanized, pre-painted steel,
with baked polyester paint
Reinforced heavy
duty shelves
Double-pane Low-E glass door
for high ambient condition
Durable PVC frame

8
EVAPORATOR CONDENSER
DRIER
CAPILLARY
COMPRESSOR
DISCHARGE
EVAPORATOR FAN MOTOR
CONDENSER
FAN MOTOR
SUCTION
LEGEND
GAS FLOW
B. Refrigeration Circuit

9
Sequence Flow Chart
1. Startup/Cool Down
3. Cool Down Restart
Cycle Steps
Slight Delay at Startup
Power On
CTh in control
3-min. Comp on timer starts
EvapFM energized Comp energized
ConFM energized
EvapFM energized
EvapFM energized Comp de-energized ConFM de-energized
EvapFM energized Comp de-energized ConFM de-energized
Comp energized ConFM energized EvapFM energized
2. Cool DownAchieved
3-min. Comp off timer starts
Factory default 34°F (1.1°C)
CTh warms to 8°F (4°C) above setpoint
5. Defrost Termination
Defrost termination only by maximum time programmed
Legend: Comp-compressor ConFM-condenser fan motor CTh-cabinet thermistor EvapFM-evaporator fan motor
Note: a) EvapFM de-energizes when door is opened on. b) 3-min. minimum Comp on timer starts when Comp energizes. c) 3-min. minimum Comp off timer starts when Comp de-energizes. d) 25-min. maximum defrost time. e) Temperature displayed is frozen during defrost.
4. Defrost
Defrost initiation occurs
every 4-hrs. of cumulative
compressor run time for
25-min
II. Sequence of Operation and Service Diagnosis
A. Sequence Flow Chart

10
B. Service Diagnosis
DANGER
Risk of Fire or Explosion
Flammable Refrigerant Used
• Follow handling instructions carefully
in compliance with U.S. government
regulations.
• Do not use mechanical devices to defrost.
• Do not puncture refrigerant tubing. Risk
of re or explosion due to puncture
of refrigerant tubing; follow handling
instructions carefully.
• Component parts shall be replaced with
like components.
• Servicing shall be done by factory
authorized service personnel to minimize
the risk of possible ignition due to
incorrect parts or improper service.
• Consult instruction manual/service manual
before attempting to install or service this
product. All safety precautions must be
followed.
• Dispose of properly in accordance with
federal or local regulations.
• Do not place any potential ignition sources
in or near the appliance.
Risque De Feu Ou D'Explosion
Le Frigorigène Est Inammable
• Suivre attentivement les instructions
de manipulation conformément à la
réglementation gouvernementale.
• Ne pas utiliser d'appareils mécaniques
pour dégivrer le réfrigérateur.
• Ne pas perforer la tubulure contenant le
frigorigène. Risque de feu ou d'explosion
si la tubulure contenant le frigorigène
est perforée; suivre les instructions de
manutention avec soin.
• Les pièces des composants doivent être
remplacées par des pièces et accessoires
équivalents.
• L’entretien doit être effectué par le
personnel de service autorisé par le
fabricant an de minimiser les risques
d’inammation attribuables à l’installation
d’une pièce inadéquate ou à la mauvaise
exécution du service.
• Consulter le manuel du propriétaire/
guide de réparation avant de tenter une
réparation. Toutes les mesures de sécurité
doivent être respectées.
• Éliminer conformément aux règlements
fédéraux ou locaux.
• Ne placez aucune source d’inammation
potentielle dans ou près de l’appareil.
WARNING
• This appliance should be diagnosed and repaired only by qualied service
personnel to reduce the risk of death, electric shock, serious injury, or re.
• Risk of electric shock. Use extreme caution and exercise safe electrical practices.
• Moving parts (e.g. fan blade) can crush and cut. Keep hands clear.
• Make sure all food zones are clean after the appliance is serviced.

11
NOTICE
• Normal operating ambient temperature range is from 60°F to 86°F
(15°C to 30°C).
• Ventilation is required from the bottom front of the appliance. Keep this
area open and clear of any obstructions. Adjacent cabinets and counter
top can be installed around the appliance as long as the front grille
remains unobstructed.
• The appliance must not be located next to ovens, grills, or other high
heat producing equipment.
• The appliance must not be located in a corrosive environment.
The diagnostic table is a sequence check that allows you to diagnose the electrical
system and components. Before proceeding, check for correct installation and proper
voltage per nameplate. Always choose a neutral (W) to establish a good neutral
connection when checking high voltages.
IMPORTANT
The maximum allowable voltage variation is ±10 percent of the nameplate rating.
115VAC is used as a reference voltage when checking voltage to components.
Voltage may vary depending on power supply.
Factory Default Temperature Setpoint:
34°F (1.1°C)
Temperature Display Scale: °F.
• There is a minimum 3-min. Comp on time and 3-min. Comp off time.

12
1. Troubleshooting
a) Not Cooling
Check for correct appliance installation per the instruction manual and proper voltage per
appliance nameplate.
Not Cooling - Possible Cause
1. Power Supply a) Unplugged, off, blown fuse, tripped or defective circuit
breaker. On three-section receptacle box, only top
receptacles have power.
b) Loose connection.
c) Not within specications.
2. Cord and Plug a) Loose connection.
b) Defective.
3. Control Module
See “ll.B.1.g) Alarm Safeties” and
“ll.C. Control Module Check”
a) In alarm.
b) Defective.
4. Door Switch a) Not engaged.
b) Defective.
5. Door Switch Relay a) Loose connection.
b) Defective.
6. Fan Motors
a) Defective.
b) Dirty condenser.
7. Wiring a) Loose connection.
b) Faulty.
8. Compressor Relay (ptc) a) Defective.
9. Compressor External Protector a) Dirty condenser.
b) Condenser fan motor not operating.
c) Compressor capacitor or start relay defective.
d) Defective.
10. Compressor a) Defective.
b) Low voltage.
11. Condenser a) Dirty.
12. Refrigerant/Refrigerant Lines a) Low or overcharged.
b) Refrigerant leak.
c) Refrigerant lines restricted.
13. Filter Drier a) Defective.

13
Evaporator Frozen Up - Possible Cause
1. Evaporator a) Dirty.
2. Evaporator Fan Motor a) Fan blades binding.
b) Defective.
3. Control Module a) Defective.
4. Compressor Relay (ptc) a) Defective.
5. Refrigerant Charge/Refrigerant
Lines
a) Low.
b) Component restriction (cap tube or drier).
Refrigerator Defrost Fails to Initiate - Possible Cause
1. Control Module (4-hrs. defrost timer) a) Defective.
d) Evaporator Frozen Up
e) Defrost
b) Too Much Cooling
Too much cooling - Possible Cause
1. Cabinet Thermistor a) Defective.
c) Extreme Condensation
Extreme condensation - Possible Cause
1. Cabinet Thermistor a) Loose.
b) Installed improperly.
2. Door a) Do not shut completly (Defective gasket or hinges not
adjusted).
3. Location a) Inadequate location.
4. Environment a) High relative humidity (Over 75%).
No illumination - Possible Cause
1. Light Switch a) “OFF” position.
b) Open contact.
c) Defective.
2. Control Module a) Control Module program.
f) No Illumination

14
g) Alarm Safeties
LEDS Mains Voltage Compressor Description
R Y G on on
Off.Voltage bad (too high or too low).
Wait period. (Intelligent Time Delay).
Allows neutralisation of refrigerant pressure.
On.Voltage good. No wait time. Cooling demand.
Defrost Period. Starts after 4 hours of accumulated compressor
run time for 25 minutes.
No cool demand (NCD). Voltage is bad.
No cool demand (NCD). Wait is on.
No cool demand (NCD). In cut-out zone.
Test mode. If in the No cool demand (NCD), this forces
compressor to go on for 10 seconds.
Probe fault. Normally compressor shuts down unless specied by
customer to cycle with pre-determined time sequence.
Fault. Mains sense auto recovery possible.
Knob in off position.
KEY On/good Off/bad Not relevant Flashing Cycling Off On

15
1. Control Module Display. Before replacing CM that does not show a visible defect and that
you suspect is bad, conduct the following check procedure. This procedure will help you
verify your diagnosis.Always choose a neutral (W) to establish a good neutral connection
when checking high voltages. Also, conrm there is a good power supply and neutral
connection to CM: 115VAC.
2. Startup/Cool Down.
3. Check all wiring connections. Conrm the CTh is properly connected.
4. Check for 115VAC to neutral. If 115VAC is not present, check power supply, and wire
connections.
5. Make sure doors are closed. Next, check for 115VAC to neutral. If 115VAC is not present,
replace CM.
6. Check that Comp and ConFM energize. If not, check CTh status. See “II.D. Thermistor
Check.” If CTh ohm reading is in proper range, check for 115VAC at CM to neutral.
If 115VAC is not present, replace CM.
7. Defrost Initiation. Defrost initiation by 4 hours compressor cumulative run time. Conrm
Comp and ConFM de-energize, EvapFM continues on. Check for 115VAC at CM to neutral
for Comp and ConFM, then at CM to neutral for EvapFM.
8. Defrost Termination. Check after a 25 min. that the Comp turn on again.
Legend: CM–control module;Comp–compressor;ConFM–condenser fan motor; CTh–cabinet
thermistor; DS–door switch; DTh–defrost thermistor; EvapFM–evaporator fan motors,
MH–mullion heater; PH–perimeter heater.
C. Control Module Check

16
D. Thermistor Check
The cabinet thermistor is used for cabinet temperature control. Thermistor resistance varies
depending on temperature. The control module monitors the thermistors to control system
operation. No adjustment is required.
The defrost initiation occurs every 4 hrs. of cumulative compressor run time with a maximum
duration of 25-min.
To check thermistor resistance, follow the steps below:
1. Unplug the appliance from the electrical outlet.
2. Remove the control cover.
3. Disconnect and remove the thermistor in question.
4. Immerse the thermistor sensor portion in a glass containing ice and water for 2 to 3 min.
5. Check the resistance between the wires at the thermistor connector. Normal reading is
within 272 to 282 kΩ. If outside the normal reading, replace the thermistor.
6. Reconnect and replace the thermistor in its correct position.
7. Plug the appliance back into the electrical outlet.

17
E. Temperature Setting Dial

18
III. Refrigeration Circuit and Component Service Information
DANGER
Risk of Fire or Explosion Flammable Refrigerant Used
• Follow handling instructions carefully in compliance with U.S. government
regulations.
• Do not use mechanical devices to defrost.
• Do not puncture refrigerant tubing. Risk of re or explosion due to puncture of
refrigerant tubing; follow handling instructions carefully.
• Component parts shall be replaced with like components.
• Servicing shall be done by factory authorized service personnel to minimize the risk
of possible ignition due to incorrect parts or improper service.
• Consult instruction manual/service manual before attempting to install or service
this product.
• Dispose of properly in accordance with federal or local regulations.
• Do not place any potential ignition sources in or near the appliance.
Risque De Feu Ou D'Explosion Le Frigorigène Est Inammable
• Suivre attentivement les instructions de manipulation conformément à la
réglementation gouvernementale.
• Ne pas utiliser d'appareils mécaniques pour dégivrer le réfrigérateur.
• Ne pas perforer la tubulure contenant le frigorigène. Risque de feu ou d'explosion
si la tubulure contenant le frigorigène est perforée; suivre les instructions de
manutention avec soin.
• Les pièces des composants doivent être remplacées par des pièces et accessoires
équivalents.
• L’entretien doit être effectué par le personnel de service autorisé par le fabricant
an de minimiser les risques d’inammation attribuables à l’installation d’une pièce
inadéquate ou à la mauvaise exécution du service.
• Consulter le manuel du propriétaire/guide de réparation avant de tenter une
réparation. Toutes les mesures de sécurité doivent être respectées.
• Éliminer conformément aux règlements fédéraux ou locaux.
• Ne placez aucune source d’inammation potentielle dans ou près de l’appareil.

19
WARNING
• Wear appropriate personal protective equipment (PPE) when servicing the
appliance.
• Technician must utilize a combustible gas leak detector at all times.
• Notify everyone in the immediate area that you are working with ammable
refrigerant.
• Do not work on appliance in a conned space. Conrm area is well ventilated.
• Identify and eliminate all possible ignition points in a 10 ft. (3 m) area around service
area.
• Do not use mechanical devices to defrost.
• Use non-sparking tools.
• Class B dry chemical re extinguisher or equivalent must be available.
• Do not pressurize system above 200 PSIG during leak check procedure or prior to
evacuating refrigeration system.
• This appliance should be diagnosed and repaired only by qualied service
personnel to reduce the risk of death, electric shock, serious injury, or re.
• To reduce the risk of electric shock, do not touch the plug with damp hands.
• Unplug the appliance from the electrical outlet before servicing.
• Make sure all food zones in the appliance are clean after the appliance is serviced.

20
A. Service for Refrigerant Lines
WARNING
• Repairs requiring the refrigeration circuit to be opened must be performed by
properly trained and EPA-certied service personnel.
• Use an electronic leak detector or soap bubbles to check for leaks. Add a trace
of refrigerant to the system (if using an electronic leak detector), and then raise
the pressure using nitrogen gas (140 PSIG). Do not use R-290 as a mixture with
pressurized air for leak testing.
NOTICE
• Always recover the refrigerant and store it in an approved container. Do not
discharge the refrigerant into the atmosphere.
• Do not leave the system open for longer than 15 minutes when replacing or
servicing parts. The Polyol Ester (POE) oils used in R-290 appliances can absorb
moisture quickly. Therefore it is important to prevent moisture from entering the
system when replacing or servicing parts.
• Always install a new drier every time the sealed refrigeration system is opened.
Do not replace the drier until after all other repair or replacement has been made.
Install the new drier with the arrow on the drier in the direction of the refrigerant
ow.
• When brazing, protect the drier by using a wet cloth to prevent the drier from
overheating. Do not allow the drier to exceed 250°F (121°C).
Refrigerant leaks must be repaired as soon as they are discovered. If not, refrigerant
charge should be recovered from the system until the leak can be repaired.
When repairing a leak:
• Repair the leak properly – Remove the refrigerant, examine the leak source, determine
the reason for the leak, and carry out the proper course of action.
• Before repairing the leak, ensure that the refrigerant has been recovered and the
system purged with nitrogen when brazing.
• Be sure to remove piercing valves attached to the system after repairs are made.
1. Refrigerant Recovery
Using proper refrigerant practices, place piercing valves toward the end (crimped area)
of the high and low-side process tubes, then recover the refrigerant into an approved
container or device.