Movincool 24HFU User manual

SERVICE MANUAL
24HFU and 24HFU-1
DENSO SALES CALIFORNIA, INC.
REGISTERED TO ISO 9002
FILE NO. A5537
DSCA P/N: LA990009-0205-E
[phone] www.movincool.com
© 2000 DENSO SALES CALIFORNIA, INC.
All rights reserved. This book may not be reproduced or copied, in whole or in part, without the written permission
of the publisher. DENSO SALES CALIFORNIA, INC. reserves the right to make changes without prior notice.
MovinCool is a registerd trademark of DENSO CORPORATION.

MOVINCOOL 24HFU / 24HFU-1 SERVICE PAGE 2
FOREWORD
This manual has been published to service the MovinCool 24HFU and 24HFU-1. Both the Model 24HFU and
24HFU-1 perform the same basic function, however the 24HFU-1 has additional features. Please use this service
manual in servicing Models 24HFU and 24HFU-1.
DEFINITION OF TERMS
WARNING
Describes precautions that should be observed in order to prevent injury to the user during installation or
unit operation.
CAUTION
Describes precautions that should be observed in order to prevent damage to the unit or its components,
which may occur during installation or unit operation if sufficient care is not taken.
NOTE
Provides additional information that facilitates installation or unit operation.
GENERAL PRECAUTIONS
WARNINGS:
• All electrical work if necessary, should only be performed by qualified electrical personnel. Repair to
electrical components by non-certified technicians may result in personal injury and/or damage to the unit.
All electrical components replaced must be genuine MovinCool, purchased from an authorized reseller.
• When handling refrigerant, always wear proper eye protection and do not allow the refrigerant to come in
contact with your skin.
• Do not expose refrigerant to an open flame.
• The proper electrical outlet for MovinCool units must be equipped with a “UL” approved ground-fault
breaker to prevent electrical shock from the unit.
• When brazing any tubing, always wear eye protection and brazing tubing in a well ventilated area.

MOVINCOOL 24HFU / 24HFU-1 SERVICE PAGE 3
GENERAL DESCRIPTION
Generally speaking conventional air conditioners cool
the entire enclosed environment. They act as “heat
exchangers”, requiring an interior unit (evaporator) to
blow cool air into the interior and an exterior unit
(condenser) to exhaust exchanged heat to the out-
doors. Unlike conventional air conditioners, the
MovinCool Spot Cooling System is a spot cooler which
directs cool air to particular areas or objects.
MovinCool Spot Cooling Systems have the following
features:
1-1. Compact Design
The innovative design of MovinCool has resulted
in one compact unit, replacing the need for two
separate units.
■ Conventional Air Conditioner
1-2. Easy Transportation and Installation
With the whole cooling system built into one
compact unit, MovinCool requires no piping and
can be easily transported and installed.
1-3. Energy Conservation
MovinCool is economical because it cools only
the area or objects which need to be cooled.
■ Air Flow of MovinCool Spot Cooling System

MOVINCOOL 24HFU / 24HFU-1 SERVICE PAGE 4
CONSTRUCTION AND SPECIFICATIONS
■Construction of Models 24HFU & 24HFU-1

MOVINCOOL 24HFU / 24HFU-1 SERVICE PAGE 5
CONSTRUCTION AND SPECIFICATIONS
2-1. Basic Construction
The MovinCool Spot Cooling System is compact
in construction because the condenser and the
evaporator are enclosed in one unit. The interior
is divided into three sections. The upper front
face is equipped with the evaporator, while the
lower front face contains the drain tank. The
rear section contains the condenser, the com-
pressor and the control box.
2-2. Air Flow
Air drawn from the right side face passes
through the condenser and extracts the heat.
This hot air is blown out through the upper
exhaust air duct. Air taken in from the front face
is cooled by the evaporator and then blown
through the cooling air duct which can be turned
in any direction. All the air inlets are provided
with filters, while the exhaust air duct is pro-
tected by wire mesh.
■ Air Flow
2-3. Compressor and Fans
The compressor is hermetically sealed. One
motor is used with two centrifugal fans to draw
air across the evaporator and condenser.
2-4. Drain Tank
The capacity of the drain tank is 5.3 gallons (20
liters). The unit is equipped with a full tank lamp
and a device to automatically stop the unit’s
operation when the drain tank reaches a level of
approximately 4.4 ±0.5 gallons (16.5 ±2 liters).

MOVINCOOL 24HFU / 24HFU-1 SERVICE PAGE 6
CONSTRUCTION AND SPECIFICATIONS
■ Specifications
ITEM/MODEL 24HFU 24HFU-1
[Rating Condition] DB 35˚C WB 28.2˚C DB 35˚C WB 28.2˚C
95˚F 83˚F 95˚F 83˚F
RH 60% RH 60%
[Features]
Power frequency___________ (Hz) 60 60
Line voltage ______________ (Volt) Single phase 230 Single phase 230
Power consumption ________ (Kw) 3.1 3.1
Current consumption _______ (Amp) 14.0 14.0
Power factor ______________ (%) 96 96
Starting current ____________ (Amp) 62 62
Power wiring ______________ (AWG) 12 (3-core) 12 (3-core)
[Cooling Unit]
Cooling capability __________ (Kcal/h) 6,000 6,000
________________________ (Btu/h) 24,000 24,000
Cooling system Direct expansion Direct expansion
[Blower]
Type of fan Centrifugal fan Centrifugal fan
Condenser - Air flow ________ (ft3/min) 1,200 1,200
Evaporator - Air flow ________ (ft3/min) 706 706
Motor output ______________ (Kw) 0.55 0.55
[Compressor]
Type Hermetic scroll Hermetic scroll
Output___________________ (Kw) 1.6 1.6
Refrigerant type R-22 R-22
Refrigerant amount _________ (kg) 0.85 0.85
________________________ (lbs) 1.87 1.87
[Safety Device]
Compressor overload relay With With
Fan motor protector With With
Drain switch With With
Anti-freezing thermostat With With
High pressure switch With With
Restart relay - power interruption Without With
Time delay relay Without With
[Dimensions and Weight]
W x D x H ________________ (mm) 490 x 730 x 1200 490 x 730 x 1200
________________________ (inch) 19.3 x 28.7 x 47.2 19.3 x 28.7 x 47.2
Weight___________________ (kg) 107 107
________________________ (lbs) 235 235
[Operating Conditions]
Intake air temperature range 45˚C (113˚F), RH ≤50% 45˚C (113˚F), RH ≤50%
to 25˚C (77˚F), RH ≥50% to 25˚C (77˚F), RH ≥50%
[Control Device]
Temperature control Without With
Specifications are subject to change without notice.

MOVINCOOL 24HFU / 24HFU-1 SERVICE PAGE 7
REFRIGERANT SYSTEM
■ Refrigerant System
The component parts of the refrigerant system include the following:
• Compressor • Evaporator
• Condenser • High pressure switch
• Capillary tube • Modulating tank
These parts are all connected by copper piping. All the connections have been brazed.
Condenser Modulating Tank
Evaporator
Capillary Tube
High Pressure Switch
Compressor

MOVINCOOL 24HFU / 24HFU-1 SERVICE PAGE 8
REFRIGERANT SYSTEM
3-1. Compressor
The compressor used for the unit is hermetically sealed. The compressor and the compressor motor are in
one casing.
3-1-2. Compressor Operation
1) Compression in the scroll is created
by the interaction of an orbiting spiral
and a stationary spiral. Gas enters
the outer openings as one of the
spirals orbits.
2) The open passages are sealed off as
gas is drawn into the spiral.
3) As the spiral continues to orbit, the
gas is compressed into two increas-
ingly smaller pockets.
3-1-1. Compressor Theory of Operation
The scroll utilizes an involute spiral which, when matched with a mating scroll form, generates a
series of crescent-shaped gas pockets between the two members. During compression, one scroll
remains stationary (fixed scroll) while the other form (orbiting scroll) is allowed to orbit (but not rotate)
around the first form. As this motion occurs, the pockets between the two forms are slowly pushed to
the center of the two scrolls while simultaneously being reduced in volume. When the pocket reaches
the center of the scroll form, the gas, which is now at a high pressure, is discharged out of a port
located at the center. During compression, several pockets are being compressed simultaneously,
resulting in a very smooth process. Both the suction process (outer portion of the scroll members)
and the discharge process (inner portion) are continuous.

MOVINCOOL 24HFU / 24HFU-1 SERVICE PAGE 9
REFRIGERANT SYSTEM
4) By the time the gas arrives at the
center port, discharge pressure has
been reached.
5) Actually, during operation, all six gas
passages are in various stages of
compression at all times, resulting in
nearly continuous suction and dis-
charge.
NOTE
Upon compressor shut-off, the compressor may
run backward for a moment or two until internal
pressures equalize. This has no effect on com-
pressor durability but may cause an unexpected
sound after the compressor is turned off and
should not be diagnosed as a malfunction.
3-2. Condenser
The condenser is a heat exchanger whose
copper tubes are covered with thin aluminum
projections called spine fins. Heat is given off
and absorbed by air being pulled across the
condenser fins by the centrifugal fan and then
expelled through the exhaust air duct.

MOVINCOOL 24HFU / 24HFU-1 SERVICE PAGE 10
REFRIGERANT SYSTEM
3-3. Capillary Tube
The capillary tube is a long thin tube and its line
flow resistance serves as an expansion valve.
The length and the inner diameter of the capil-
lary tube are determined according to the
capacity of refrigeration system, operating
conditions and the amount of refrigerant.
The capillary tube causes the high pressure,
high temperature liquid refrigerant sent from the
condenser to expand rapidly as the refrigerant is
sprayed out through the fixed orifice in the
capillary tube. As a result, the temperature and
state of the refrigerant become low and mist-
like, and therefore it evaporates easily. ■ Capillary Tube
Capillary Tube Dimensions
Qty Purpose of Use I.D. (mm) Length (mm)
1 For cooling ∅1.5 ±0.05 540
3-4. Evaporator
The evaporator, like the condenser, is a heat
exchanger covered with spine fins. Heat is
removed from the air being pulled across the
evaporator by the centrifugal fan and the
resulting cool air is expelled through the cooling
air ducts.
3-5. Modulating Tank
The modulating tank consists of a copper pipe
and tank sections, each being separated from
the other. The pipe connects to the evaporator
outlet at one end and to the compressor at the
other; the tank connects to the evaporator inlet.
The modulating tank is covered with insulation to
reduce thermal effects of ambient temperature.
It varies the quantity of refrigerant in the refriger-
ating cycle for optimum operating condition; it
stores part of refrigerant under light load and
delivers additional refrigerant to the cycle under
heavy load.
■ Modulating Tank
3-6. High Pressure Switch
The high pressure switch prevents the con-
denser and compressor from being damaged by
excessively high pressure in the high pressure
line of the refrigeration cycle. The switch is
normally closed. The snap disk responds to
variations in pressure and, if pressure is abnor-
mally high, the snap disk moves down to push
the pin down, causing the internal contacts to
open. This generates a signal to open the
auxiliary relay.
Possible causes of this trouble include:
(1) The condenser air filter is dirty, restricting
air flow.
(2) The condenser blower is defective. ■ High Pressure Switch

MOVINCOOL 24HFU / 24HFU-1 SERVICE PAGE 11
REFRIGERANT SYSTEM
■ Refrigerant System Piping
Condenser
Inlet Pipe
Compressor
Discharge
Pipe
Condenser
Outlet Pipe
Compressor Suction
Pipe (insulated) Connecting Tube (condenser to capillary tube)
Connecting Pipe
(evaporator to compressor)
Capillary Tube
Evaporator
Outlet Pipe
Evaporator
Inlet Pipe

MOVINCOOL 24HFU / 24HFU-1 SERVICE PAGE 12
ELECTRICAL SYSTEM • 24HFU
■ Electrical System and Control Box for Model 24HFU
24HFU

MOVINCOOL 24HFU / 24HFU-1 SERVICE PAGE 13
ELECTRICAL SYSTEM • 24HFU
4-1. Basic Operation of MovinCool Modelp 24HFU Electrical Circuit
The three basic modes of operation are as follows:
1) Control Switch in “OFF”position:
a. Current flows through terminals 5 and 2
of the control switch (CS) and to the coil
of the auxiliary relay (RX). (A and B.)
b. Two contacts (RX) of the auxiliary relay
are closed by electromagnetic force. The
closed contact RX (terminals 19 and 20)
allows current to flow directly to the
auxiliary relay coil and hold the contact in
a closed position.
■ Operation in “OFF” position
2) Control Switch in “FAN”position:
a. Current also flows through the control
switch (CS) to the fan motor (MF).
b. Current flows through the contact (termi-
nals 19 and 20) of the auxiliary relay and
its coil, and remains closed.
■ Operation in “FAN” position
NOTE
Symbol indicates alternating current.
3) Control Switch in “COOL”position:
a. The contacts of the auxiliary relay remain
closed as mentioned in step 2) b.
b. Current flows to the fan motor (MF).
c. Current also flows to the anti-freezing
thermostat (THS) contact, to the coil of
the relay for the compressor motor
(MCC) (A and B) and the auxiliary relay
contacts.
d. Two contacts of the relay for the com-
pressor motor (MCC) are closed by the
electromagnetic force. Current then
flows to the compressor motor (MC).
■ Operation in “COOL” position

MOVINCOOL 24HFU / 24HFU-1 SERVICE PAGE 14
ELECTRICAL SYSTEM • 24HFU
4-2. Control Box
4-2-1. Capacitor
The capacitor is used to boost power
output to the fan motor and the compres-
sor at start-up.
The specifications of each capacitor are
shown below.
■ Circuit of Auxiliary Relay
■ Auxiliary Relay
4-2-2. Auxiliary Relay
This auxiliary relay is normally closed
when the unit is in operation (FAN or
COOL), and supplies power to the com-
pressor relay and the fan motor. In the
following cases, however, the relay opens
to interrupt power to the compressor and
the fan motor.
•When the drain tank is filled with water.
(Drain switch OFF.)
•When the high pressure becomes
excessively high. (High pressure switch
OFF.)
When current flows across A and B,
terminals 11 and 12, 13 and 14, 15 and
16, 19 and 20 conduct.
Specifications:
Rated Voltage AC 240V
Rated current 15 amps
UL Listed File No. E112482
Capacitor Registrant Voltage Capacitance
(Volt) (mF)
For fan motor 440 12.5
For compressor 370 40
4-2-3. Compressor Relay
The compressor relay is closed when the
unit is operating in COOL mode, and
supplies power to the compressor. How-
ever in the following cases, the relay
opens to cut off power to the compressor.
•When the auxiliary relay is opened.
(Drain switch OFF or high pressure
switch OFF.)
•When the evaporator has frosted.
(Thermostat OFF.)
Specifications:
Rated Voltage AC 230V
Rated Current 30 amps
UL Listed File No. E43028
■ Circuit of Compressor Relay
■ Compressor Relay

MOVINCOOL 24HFU / 24HFU-1 SERVICE PAGE 15
ELECTRICAL SYSTEM • 24HFU
4-3. Control Switch
The control switch is employed to start or stop
operation. This switch is a 250V, 20A rating
rotary type (3-position). The switching positions
are OFF-FAN-COOL. Each contact is switched
by the cam uniting with the shaft.
Switch Terminals OFF FAN COOL
(5) - (2) Conduct OFF OFF
(5) - (1) OFF Conduct OFF
(5) - (4) OFF Conduct Conduct
■ Control Switch
CF1
CF2
RX12
■ Fan Motor
■ Thermostat
4-4. Fan Motor
The fan motor is a single phase, induction type
motor which drives fans on the evaporator side
and the condenser side at the same time.
Specifications:
Rated Voltage AC 230V
Rated Output 552 Watts
UL Listed File No. E49807
4-5. Compressor Motor
The compressor motor is a single phase motor
and is contained within the same housing as the
compressor.
Specifications:
Rated Voltage AC 230V
Rated Output 1600 Watts
NOTE
An internal overload relay is used to protect the
compressor motor and fan motor. This relay is
built into the compressor motor and fan motor and
will interrupt the flow of current when there is an
overcurrent situation or if abnormally high
temperature builds up in the compressor motor or
fan motor.
4-6. Anti-freezing Thermostat
If the evaporator has frosted, the thermostat
contacts open to stop the compressor and the
unit continues to operate on “FAN”mode. Once
the evaporator has defrosted, the contacts close
to restart the compressor and the unit operates
in “COOL”mode. The thermostat heat sensing
tube is mounted at the evaporator outlet tube
and is insulated from surrounding air by heat
insulating material. The thermostat contacts are
opened at -1.5˚C and closed at +14.5˚C.

MOVINCOOL 24HFU / 24HFU-1 SERVICE PAGE 16
ELECTRICAL SYSTEM • 24HFU
4-7. Drain Switch
The drain switch interrupts both the compressor motor circuit and the fan motor circuit when the drain water
accumulates approximately 4.4 gallons (16 liters) in the drain tank. This also illuminates the full tank lamp
on the control panel and stops the operation. This system adopts a 250V, 3Arating micro switch for this
function. When drain water accumulates approx. 4.4 gallons (16 liters) in the drain tank, the drain tank base
plate, which is supported at its fulcrum (a), is pushed down in the arrow direction as shown in the figure
below. When the drain tank base plate is forced down, “portion A”located at the top of the drain tank base
plate turns off the contacts (1) - (2) of the micro switch. Since this breaks the auxiliary relay (RX) circuit, the
auxiliary relay contacts are turned off to break the compressor circuit and the fan motor circuit. At the same
time, the contacts (1) - (3) are turned on to light the full tank warning lamp.
■ Operation of Drain Switch
When the drain tank is removed (or the water in the drain tank is drained), portion “A”of the drain tank base
plate returns to its original position by the elasticity of the coil spring. Then the contacts (1) - (3) turn off,
extinguishing the full tank lamp. At the same time, the contacts (1) - (2) turn on. Under this condition, turn
the control switch to FAN or COOL position to start operation.
4-8. Condensate Pump Kit <OPTIONAL>
Models 24HFU and 24HFU-1 come standard with a condensate tank, which collects the water that forms on
the evaporator during normal cooling operation. If the unit is required to operate continuously without
periodic emptying of this tank, a condensate pump may be needed. A condensate pump kit is available for
Models 24HFU and 24HFU-1.

MOVINCOOL 24HFU / 24HFU-1 SERVICE PAGE 17
ELECTRICAL SYSTEM • 24HFU
4-9. Wiring
■ Wiring Diagram for Model 24HFU
24HFU

MOVINCOOL 24HFU / 24HFU-1 SERVICE PAGE 18
ELECTRICAL SYSTEM • 24HFU-1
■ Electrical System and Control Box for Model 24HFU-1
24HFU-1

MOVINCOOL 24HFU / 24HFU-1 SERVICE PAGE 19
ELECTRICAL SYSTEM • 24HFU-1
UNIQUE FEATURES OF MOVINCOOL 24HFU-1
The MovinCool 24HFU-1 is a modified version of Model 24HFU. Model 24HFU-1 has several additional features,
which are described below.
4-1. Automatic Restart After Power Interruption
A restart auxiliary relay has been added to the electrical system to allow automatic restarting of the system
after a power interruption, eliminating the need for manual reset of the control switch.
Specifications:
Rated Voltage AC 240V
Rated Current 10 amps
UL Listed File No. E57520
4-2. Compressor Protection
There is a time delay circuit included in the electrical system to prevent a heavy load from being applied on
the compressor motor when restarting the system. This delay is in effect any time when the compressor is
turned on, by the control switch, thermostatic control, or resumption after blackout. (This delay is also in
effect when automatic restart after power interruption operates.) Delay time 75 ±15 seconds.
Specifications:
Rated Voltage AC 240V
In Operation 3 amps
After Operation 13 amps
Relay Time 75 ±15 sec.
UL Listed File No. E41515

MOVINCOOL 24HFU / 24HFU-1 SERVICE PAGE 20
ELECTRICAL SYSTEM • 24HFU-1
4-3. Temperature Control
The compressor is controlled by a thermostat which senses the return air temperature. This thermostat can
be set to approximate temperatures by means of the thermostat dial, located below the control switch.
1 LESS COOL →7 COOLEST
4-4. Fan Mode Control Switch
The fan motor is controlled by a switch located in the control box. There are two positions:
A. COOL-OFF
When the switch is set to the left, the fan motor is controlled by the thermostat which controls the
compressor. In this case, both the fan and the compressor stop when the thermostat detects suffi-
ciently low intake air temperature. When the temperature increases again, the fan will restart automati-
cally. The fan motor is independent from the time delay circuit which protects the compressor, conse-
quently the fan will begin approximately 75 seconds before the compressor restarts.
B. COOL-FAN
When the switch is set to the right, the fan motor will be controlled only by the control switch. As long
as the unit is set to FAN or COOL, the fan will operate continuously. (This is the factory default setting.)
Specifications:
Rated Voltage AC 240V
Rated Current 20 amps (Power Factor COS r = 1)
Off 16.1 ±1.1 (˚C)
Diff 2.8 ±1.1 (˚C) (ON: 18.9 (˚C))
UL Listed File No. SA512
CAUTION
Because there is a built-in delay circuit to protect the compressor, the compressor will never start up immedi-
ately, regardless of the type of operation. This delay is part of the normal operation of Model 24HFU-1 and
should not be diagnosed as a malfunction.
Specifications:
Rated Voltage AC 250V
Rated Current 16 amps
UL Listed File No. E98133