Munters HCUw Manual

Patent Nos. 6,711,907 & 6,557,365
Additional US, International and Chinese patents pending
OPERATING & MAINTENANCE
MODEL HCUw
R410a Refrigerant
OM 0009 - 06

Table of Contents
i. Cover Sheet
ii. Table of Contents
1 Introduction
2 Safety
3 Installation (pg.3)
3.1 Lifting and Inspection
3.2 Positioning the Unit
3.3 Installing the Hoods
3.4 Connecting the Supply Air Duct
3.5 Connecting the Condensate Drain
3.6 Electrical Connections
3.7 Connecting the Control System
3.8 Start-up Checks
4 Operating Instructions
(pg.6)
4.1 Controls
4.2 Starting the Unit
4.3 Unit operation
4.4 Using the Carel microprocessor
4.5 Shut down
4.6 Adjusting the supply airflow
4.7 Condenser and Reactivation Fan Control
5 Maintenance
(pg.18)
5.1 Quick Maintenance Check
5.2 Suggested Maintenance Schedule
5.3 Inspecting the Ductwork
5.4 Replacing the Air Filters
5.5 Inspecting the Seals
5.6 Inspecting the Fans
5.7 Inspecting the Wheel Drive Motor and Belt
5.8 Inspecting the Roller Wheels
5.9 Electronic Controls
5.10 Checking the Drip Tray and Drain
5.11 "Removing and Replacing the Honeycombe® Wheel,
Drive Belt, and/or Seals"
5.12 Inspecting the Wheel
5.13 Cleaning the Wheel
5.14 Warranty
6 Troubleshooting
(pg.24)
6.1 Dehumidifier Operating Principle
6.2 Troubleshooting
Appendix
A Troubleshooting
(pg.28)
B Wiring diagrams (pg.29)
C Variable Frequency Drives (pg.41)
D Sequence of Operation (pg.74)
E Equipment Data (pg.76)
F Afterheat (pg.82)

1
1 Introduction
This manual includes installation, operation, and troubleshooting instructions for the HCU unit. The
engineers at Munters DryCool have designed the HoneyCombe®dehumidifier using state-of-the-art
technology. The unit is durable, simple to operate, and needs very little maintenance.
The HCU is controlled by an external Novar IOM controller.
The HCU unit is designed to provide an economical way to bring makeup air into the space and control
space temperature and humidity at the same time. The HCU first uses a cooling coil to cool and
dehumidify the air. The air is cool and saturated with moisture as it leaves the cooling coil. The air is then
passed through a desiccant wheel which converts the latent heat (moisture) into sensible heat. This
raises the air temperature to a neutral condition and at the same time lowers the dew point. The desiccant
wheel is reactivated by recycling heat from the condenser coil. The HCU can provide cooling only by
simply turning off the desiccant wheel.
A conventional air conditioner cools the air and removes some of the moisture. It works well at design
conditions of high ambient temperature with mild humidity conditions. However, at more moderate
ambient temperature conditions with greater moisture levels, the conventional air conditioner will overcool
the air and not dehumidify sufficiently.
The HCU can provide years of trouble-free service if you follow the recommendations listed in this
manual. We strongly recommended that you read this entire manual. The manual describes how to get
the best service from your unit. While a DryCool dehumidifier is easy to operate, it is a bit different from
most air handling equipment.
If you do not understand a part of this manual, or have a question concerning the dehumidifier, call the
DryCool Technical Service Department at [phone], and speak with one of the Service Operation
Technicians.

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2 Safety
Munters is concerned about the safety of anyone who uses or services the HCU unit. Some of the parts
inside the HCU can be dangerous if an untrained person tries to service the unit. Throughout this
manual, we have pointed out some of the hazards that may occur in the use of the HCU. We have also
listed the precautions that you should take to avoid these problems.
In this manual, we will use three different kinds of messages to warn you of possible problems:
Immediate hazard that will result in severe personal injury or death.
Hazard or unsafe practice that may result in severe personal injury or death.
Hazard or unsafe practice that could result in minor personal injury or property
damage.
Please keep these points in mind as you use or service the unit:
The HCU is wired for up to 480V AC. The unit can produce enough voltage and
current to cause serious injury or death. Always turn off and lock out the power
before you work inside the unit. Do not work with the electrical parts unless you
are a trained electrician.
The HCU unit includes three or four fans - the supply, reactivation, and
condenser fans. Keep your hands away from the fans while the unit is turned on.
Before working with the machine, allow enough time for the fans to come to a
complete stop.
The wheel used in the HCU is heavy. When working near the wheel when it is
inside the unit, and the wheel is propped up, use blocks to prevent the wheel
from moving accidentally.
This unit is designed for outdoor use. However, it is not waterproof and
weatherproof unless all panels are secured in place and doors closed.
During normal operations, do not run the unit unless the panels are in place and
doors closed.
PLEASE READ THIS ENTIRE MANUAL. PLEASE FOLLOW THE INSTRUCTIONS CAREFULLY AND
COMPLETELY. PLEASE PAY PARTICULAR ATTENTION TO THE SAFETY INSTRUCTIONS AND
PRECAUTIONS.

3
3 INSTALLATION
3.1 LIFTING AND INSPECTION
1. Unit must be lifted by crane using all 4 lifting points located on the sides of the unit. The crane must
be selected to handle the weight shown on the General Arrangement drawing. Spreader bars that are
2” to 4” wider than the unit width must be used to prevent the rigging cables from squeezing the top of
the unit. Failure to do so will damage the unit.
2. When the unit arrives, check it immediately for signs of shipping damage. If you do notice any
damage, report it to the shipping company and to Munters right away.
3. The control enclosure is mounted behind a door on the side of the unit. The electrical controls are
located directly behind the control panel door. The door is secured with a bolt and locking nut to
prevent unauthorized access. This bolt and nut should be replaced after installation or servicing or
may be replaced with a padlock.
• Check for any signs of damage.
• Check the tightness of all electrical connections. Carefully check the power wiring terminals.
• Be sure all control relays are firmly seated in their sockets.
3.2 POSITIONING THE UNIT
1. The HCU must be installed and operated outdoors. The unit is mounted on a roof curb where bottom
discharge and/or return is featured. The curb should be installed level. The curb must have a
neoprene gasket ½” thick x 1 ½” wide installed completely around the perimeter prior to setting the
unit in place.
CAUTION: Failure to install the roof curb gasket may result in rain water leaks.
2. Allow clearances around the unit on all sides for maintenance access.
3. The unit should have free access to outdoor air.
3.3 INSTALLING THE HOODS
1. Air intake hoods must be installed over the condenser coils and on the outside air inlet on the side of
the unit opposite the condenser coil. There are 12 condenser coil hoods (40” wide) and 4 makeup air
inlet hoods (30 ½” wide).
2. Condenser coil hoods (40” wide)
a. Remove any shipping covers or materials from the face of the condenser coil. Remove coil
support screws on the left side of the condenser coil. Place the first hood in the upper left hand
corner so that the pre-punched holes in the hood line up with the pre-punched holes on the
condenser coil flanges on the left side. Install 6 sheet metal screws (furnished).
b. Place the next hood directly below the first hood. The top of the second hood should be butted
against the bottom of the first hood and the pre-punched holes should line up. Install 6 sheet
metal screws. The third and fourth hoods are installed likewise. The top hood shall have an
additional 5 screws installed in the pre-punched holes along the top flange.
c. Install the remainder of the hoods in the same fashion.
3. Makeup air inlet hoods (30 ½” wide)
a. Place the first hood at the top of the makeup air inlet louver (the inlet louver has vertical aluminum
fins about ¾” apart). The flanges should sit on the face of the inlet louver frame. The top of the
hood is aligned with the top of the inlet louver frame. Install 3 screws on each side and 4 screws
along the top of the top hood through the pre-punched holes.
b. Place the second hood directly below the top hood and attach with 3 screws on each side.

4
c. The third and fourth hoods mount under the top 2 hoods in like fashion.
3.4 CONNECTING THE SUPPLY AIR DUCT
a. Duct connections must be completed according to U.M.C., A.M.C.A., S.M.A.C.N.A., and/or state
and local code requirements. Refer to the plans and specifications supplied with the machine.
b. This machine will require a duct from the supply air outlet to the conditioned space. The duct
should be sized appropriately and insulated. At the supply air outlet on the HCU, install a section
of flex-duct. (This will prevent the ductwork from transmitting vibrations).
3.5 CONNECTING THE CONDENSATE DRAIN
1. The unit includes a condensate drain located on the outlet of the evaporator coil. Install a proper
vented P-trap in the drain line and connect this outlet to a suitable drain. IMPORTANT: The P-trap is
vented to atmosphere by means of an open tee fitting. This tee must be left open as is. Do not cap or
extend upward from the tee.
2. The trap must be constructed according to U.M.C. and/or state and local code requirements. Refer
to the plans and specifications supplied with the machine.
3.6 ELECTRICAL CONNECTIONS
1. The electrical service entrance is through the bottom of the unit directly into the electrical panel. The
exact location is shown by a label.
2. Electrical service and control wiring must be made according to NEC and/or state and local code
requirements. Follow these codes and specifications when installing any control devices. Appendix
B shows detailed wiring diagrams for the units.
3. The HCU is designed to operate on three-phase AC at 208/3/60, 230/3/60, or 460/3/60 as specified.
Be sure the line voltage matches the voltage required by the machine.
The HCU is wired for 208 - 480 Volts. The unit can produce
enough voltage and current to cause serious injury or death.
Always turn off the power before you work inside the unit. Follow
standard lockout tag-out procedures. Do not work with the
electrical parts unless you are a trained electrician.
Be sure the unit is connected to a source with the correct line
voltage. If you connect a higher voltage than the unit can
accept, you may create a shock hazard or damage the machine.
The correct line voltage is listed on the nameplate on the
machine.
4. Bring in the main power cable from a fused disconnect through the bottom of the unit to the
disconnect inside the control panel. The fuse must be a time delay type. Unit FLA, MCA, and MOP
are shown on the Equipment Data Sheet (APPENDIX E).
4. Properly connect the chassis of the HCU to a good earth ground.
5. The unit may be wired with an interlock to the smoke detector system in the building. Please refer to
the wiring diagram
6. Before operating, check to see that the phasing is correct. With any given combination of wiring
connections for L1, L2 and L3, there is a 50:50 chance that the fans and compressors will be turning
backwards. To check for this, turn on the power to the unit momentarily and check for correct rotation
of the condenser fan. The condenser fan is mounted on the top of the unit and can be easily viewed
for rotation. If the fan is running backwards, turn off the unit and disconnect the power. Reverse any
two of the three leads to the main power terminal block. It is important that the machine not be left

5
incorrectly wired.
3.7 CONNECTING THE CONTROL SYSTEM
The unit is controlled by a Novar IOM or Danfoss controller with relay outputs. Digital inputs monitor
faults. With this method of control, the fan relay on the IOM turns the unit on. The relays on the BMS IO
card call for stages of cooling, dehumidification and heating as conditions require.
The HCU has eight (8) control inputs for the functions of fan, cooling stage 1, cooling stage 2, and
dehumidification. Heating stages 1 through 4 are controlled directly by the IOM. See Section 4 for details.
The HCU microprocessor is connected to the Novar IOM according to wiring diagram 5900-03 for a single
heater unit or 5900-00 for a two heater unit (Appendix B).
3.8 START-UP CHECKS
There are a couple of points that should be checked before the unit can be released for normal service:
1. A unit using three-phase AC may be wired so the compressor is operating backwards. A unit that is
wired this way may make an unusual sound, and will not produce any cooling. The microprocessor
will indicate “Compressor Low Diff Press” alarm after a 5 minute delay. To correct this problem, see
Section 3.5. If the compressors will not energize, check adjustment on the Airflow switch. The supply
fan must close the airflow switch for the compressors to operate.
2. Turn on power to the unit and allow it to operate normally for about 30 minutes. (This will allow time
for the temperatures inside the unit to stabilize.) You should run this test at a time of day when the
HCU needs to run dehumidification. Using a simple probe thermometer, check the temperatures
leaving (LAT) the cooling coil, desiccant wheel, and condenser coil. The cooling coil LAT should be
15 to 30 degrees F cooler than ambient. The wheel LAT should be 10 to 15 degrees F warmer than
the coil LAT. The condenser coil LAT should be at least 112 degrees F.

6
4 OPERATING INSTRUCTIONS
4.1 CONTROLS
The unit is controlled and monitored by a Novar IOM or Danfoss controller. The HCU has a
microprocessor to supervise and control all internal functions. The IOM provides eight dry contact
closures to control the supply fan and stages of: cooling, dehumidification, and heating as shown on the
wiring diagram. The controller also monitors inputs as shown on the wiring diagram.
4.2 STARTING THE UNIT
Turn the disconnect switch for the HCU on.
The unit will start when the external FAN contacts close on the IOM. The unit will also start when either
the COOL, DH, or HEAT contacts close.
4.3 UNIT OPERATION
The controller will sense space conditions and call for two stages of cooling, DH, or stages of heating as
required to maintain space conditions. Digital inputs 4 and 7 must be connected with a jumper wire
(terminals 37 and 40). A call for dehumidification will energize compressor A. After a settable delay period
called “Comp B On” under User Settings: DEHUM OVERRIDES (default 30 minutes), compressor B will
start if the call for DH is still present. When the call for dehumidification is dropped, compressor B will de-
energize and compressor A will continue to run for a period of time called “Comp A Off” under User
Settings: DEHUM OVERRIDES (default 15 minutes). Stage 2 DH will not energize if:
1. Outside air temperature is below set point: OUTSIDE AIR TEMPERATURE Comp B Set: (default)
65°F.
2. Outside air damper DI8 is not energized.
3. Suction pressure is below set point: COMP B – CYCLE ON MIN SUCTION PRESSURE Set
point: (default) 128 psig (R410a).
NOTE: The night setback digital input (DI8 Outside Air Damper) must be jumpered to terminal 20. When
DI8 is not energized, compressor B will not operate.
The HCU microprocessor can be set for temperature priority or humidity priority mode of operation. In
Humidity priority (default position), the desiccant wheel will operate along with the compressor anytime
DH is called for by the external controller. In Temperature priority mode, the desiccant wheel will shut off if
the external controller calls for cooling while calling for DH. This mode of operation defaults as Humidity
priority. The mode can be changed in the CONTROL SETUP screen under USER SETTINGS on the
microprocessor.
The external controller may be overridden if the outside conditions are above user adjustable set points.
There are adjustable compensations for high outdoor ambient temperature and humidity conditions to
prevent swings in indoor conditions.
This is accomplished by setting desired “overrides” for differences between outdoor and desired indoor
temperature and grain levels. If the difference exceeds these adjustable overrides, the appropriate stages
of cooling or DH will remain on even though indoor conditions are met. See 4.6 USER SETTINGS.
4.4 USING THE CAREL MICROPROCESSOR
The Carel pCO2 microprocessor has a keypad and display to allow the operator to view the status of
various functions, set parameters with authorization to up to three levels of security, and to troubleshoot
problems that may occur.
The keypad and display are located on the microprocessor inside the control panel. CAUTION! There is
high voltage inside the control panel. Do not touch anything other than the keypad on the display.

7
Operation of the Carel pCO2 Microprocessor
The pCO2 microprocessor has a keyboard and display to allow the operator to view the status of various functions, set
parameters with authorization to up to three levels of security, and to troubleshoot problems that may occur.
Alarm (bell icon) - is used to view and alarm. An alarm is indicated when the button is illuminated in red.
Esc - is used to return to the Main Menu or go back one screen.
Up and Down arrows are used to scroll the display up or down, to toggle values, or to increase or decrease
Enter ( ) is used to move the cursor when changing setpoints or to accept a value entered.
Prg button is not used and is inactive.
Pressing the UP and Down arrows simultaneously will display the Main Screen that will display the HCU model and the
software version with version date.
*** MAIN MENU ***
STATUS
CURRENT ALARMS
DATE / TIME
USER SETTINGS
RUN TIMES These are the 10 fields that appear on the Main Menu
SERVICE SETTINGS
FACTORY SETTINGS
SENSOR CALIBRATION
DIG-IN CALIBRATION
MANUAL CONTROL
*** END ***
STATUS The STATUS field has 7 screens that show the current status of all
digital outputs, analog inputs, and analog outputs.
CURRENT STATUS
Supply Fan: ON/OFF
Outside RH: XXX.X %
Outside Temp: XXX.X º F
OUTSIDE AIR STATUS This shows outside air enthalpy, a measure of total
heat content of the air.
Enthalpy: XX.X btu/lb
COMPRESSOR - STATUS
CompA: ON/OFF CompB: ON/OFF
Suct Press: XXX psi
Disc Press: XXXpsi
CONDENSER FAN STATUS This shows the % of full RPM of the reactivation and/or condenser
fan. REACTIVATION STATUS screen shows Current Setpoint for
discharge pressure, which is set for 220 psi for cool-only mode of
operation or 260 psi for DH mode. The React Fan Out
Wheel: ON/OFF
Current Setpoint: 340psi/444psi
React: 0 - 100.0% Cond: 0 - 100%
CURRENT STATUS

8
PostCool Temp: XXX.X º F
Leaving Temp: XXX.X º F
CURRENT GRAIN STATUS
Outside:
PostCool:
Leaving:
MISC OUTPUTS
Coil Damp: ON/OFF WhlD: ON/OFF
Afterheat Stage: ON/OFF
Supply Heat Out: 000.0 - 100.0%
CURRENT ALARMS When the unit is in the alarm mode, the alarm button on the
microprocessor will be illuminated in red.
***ALARM*** The CURRENT ALARMS field will show any current alarms, but the
easiest way to view the alarm(s) is to press the red alarm button to
show the first current alarm on the display. Press the down-arrow to
view any additional alarms. When there are no more corrent alarms,
the NO MORE ALARMS screen will appear. Press the enter button
to clear the alarms after the problem causing the alarms is rectified.
Alarms must be manually reset except where noted below.
SUPPLY FAN FAULT
***ALARM*** Compressor High Discharge Lockout occurs when discharge
pressure reaches 600 psi.
COMPRESSOR A
HIGH DISCHARGE LOCKOUT
***ALARM*** The difference between suction and discharge pressure is ≤75 psi
after the compressor has run for 5 minutes
COMPRESSOR A LOW PRESS DIFF
***ALARM*** Reactivation fan fault occurs when the reactivation fan VFD or
contactor indicated that the reactivation fan has tripped.
REACTIVATION FAN FAULT
***ALARM*** Wheel fault is occurrs when DH is on and the temperature
difference between the wheel entering temperature and the wheel
leaving air temperature is less than 5ºF after a delay of 30 min.
WHEEL FAULT
***ALARM*** Indicates that the outside air temperature is less than the minimum
air temperature allowed for the compressor to operate. This is
adjustable under factory settings. Outside temperature cooling
shutoff will automatically reset when the temperature rises above
the setpoint.
OUTSIDE TEMPERATURE
COOLING SHUTOFF
***ALARM*** Indicates that the outside air temperature is less than the minimum
air temperature allowed for the supply fan to operate and bring in
outside air. This is adjustable under user settings. Outside
temperature fan shutoff will automatically reset when the

9
temperature rises above the setpoint.
OUTSIDE TEMPERATURE
FAN SHUTOFF
***ALARM*** Low suction pressure is indicated when the suction pressure drops
below 25 psi. The compressor is locked out.
LOW SUCTION PRESSURE
COMPRESSOR A
NO MORE ALARMS
PRESS DOWN TO REVIEW
PRESS ENTER TO CLEAR
DATE / TIME
Date / Time Settings
00:00
XX / XX / XXXX
DAY OF WEEK
RUN TIMES
CURRENT RUN TIMES The CURRENT RUN TIMES displays the time that each digital
output has been in its present state, either on or off.
TOTAL RUN HOURS The TOTAL RUN HOURS displays the total number of hours each
digital output has been in the on state since the unit was new.
SENSOR CALIBRATION SENSOR CALIBRATION is used to "zero" a sensor that may be off
by a certain amount.
ENTER LEVEL 2 PASSWORD: 0002 In order to access SENSOR CALIBRATION, the Level 2 password
must be entered.
*CALIBRATE READINGS* This is an example of what will appear in the sensor calibration
screens. The calibration may be either a positive or a negative
value.
Comp A Suction Pres
CALIBRATION: 00 psi
Actual: 75 psi
DIG-IN CALIBRATION DIG-IN CALIBRATION is used to initially set up digital inputs. The
logic requires that all digital inputs are active if closed.
ENTER LEVEL 3 PASSWORD: 0003
DIGITAL INPUT 1 This is an example of a digital calibration screen.
SUPPLY FAN
Current: OPEN
Active If: CLOSED
MANUAL CONTROL Manual control is used by the service technician when required to
set up or troubleshoot a unit. The level 2 password must be entered
to gain access to the manual control screens.
ENTER LEVEL 2 PASSWORD: 0002

10
DIGITAL INPUTS Digital inputs may be manually forced on to simulate a call from the
control system to bring on any of the functions. To do this, the
CONTROL STATE must be changed to MANL. Now changing the
INPUT STATE to CLOSED will initiate that function.
DIGITAL INPUT #1
CONTROL STATE : AUTO / MANL
INPUT STATE: OPEN / CLOSED
SUPPLY FAN
ANALOG INPUTS Analog inputs may be manually forced to a value to test the system.
For example, the discharge pressure may be forced to a high value
to test the lockout function.
ANALOG INPUT #1
CONTROL STATE: AUTO / MANL
INPUT VALUE: XXX psi
DISC PRESS COMP A
DIGITAL OUTPUTS Digital outputs may be forced to a manual position. Extreme caution
must be used when forcing digital outputs because all safety
features are bypassed. For example, the microprocessor will not
shut off the compressor due to high discharge pressure. It is much
safer to force the digital input which will leave safety functions
operational.
DIGITAL OUTPUT #1
CONTROL STATE: AUTO / MANL
OUTPUT STATE: OPEN / CLOSED
SUPPLY FAN STATUS
ANALOG OUTPUTS Analog output may be forced to run the reactivation fan to a certain
speed for troubleshooting purposes.
ANALOG OUTPUT #1
CONTROL STATUS: AUTO / MANL
OUTPUT VALUE: XXX.X%
REACTIVATION FAN
HCU Carel IO and Setpoints
Digital Inputs Symbol
1 Fan ID1
2 Cool Stage 1 ID2
3 Cool Stage 2 ID3
4 DH Stage 1 ID4
5
6
7 DH Stage 2 (Jumpered to ID4) ID7
8 Outside air damper (Jumpered to ID1) ID8
9 Supply fan fault ID9
10 Reactivation fan fault ID10
11 Condenser fan fault ID11
12 ID12

11
13 Wheel Motor fault ID13
Analog Inputs Sensor/transmitter Location
1 Compressor A Discharge Compressor A liquid line
2 Compressor A Suction Compressor A suction line
3 Ambient Humidity In front of DX coil
Calculated ambient grains/lb
4 Ambient Temperature In front of DX coil
5 Post cool temperature Centered on leaving side of DX coil
6
7
8 Wheel leaving air temp After supply fan (no afterheat); Centered
on leaving air side of supply heater
(afterheat)
Digital Outputs
1 Supply fan NO1
2 Compressor A NO2
3 Compressor B NO3
4 Desiccant wheel NO4
5 Reactivation fan NO5
6
7
8
9 Alarm NO9
10 Liquid Line NO10
11
12 Condenser fan NO12
13 VFD Reset NO13
Analog Outputs
1 Reactivation fan Y1
2
3 Condenser fan Y3
4
USER SETTINGS Setpoint Function
SPACE SET POINTS
Temperature: 75.0F Reference setpoint for operation of
OUTSIDE TEMPERATURE OVERRIDEs
Humidity: 45.00% Reference setpoint for operation of
OUTSIDE GRAIN OVERRIDEs
Calc gr/lb:
OUTIDE TEMPERATURE OVERRIDEs
Compressor A: 99.9F When outside temp is ≥SPACE SET
POINT Temp + this value, stage 1 cooling
will energize
Compressor B: 99.9F When outside temp is ≥SPACE SET
POINT Temp + this value, stage 2 cooling
will energize
OUTIDE GRAINS OVERRIDEs

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Compressor A: 99gr When outside grains is ≥SPACE SET
POINT grains + this value, stage 1 DH will
energize
Compressor B: 99gr When outside grains is ≥SPACE SET
POINT grains + this value, stage 2 DH will
energize
DEHUM OVERRIDES When only one stage of DH control is
used, a call for DH will energize Com A.
Comp A Off: 15 min Stage 1 DH will remain on for this period of
time after the DH 1&2 signal is gone
Comp B On: 30 min After this initial delay, if DH 1&2 is still
called for, Comp B will energize
OUTSIDE TEMPERATURE
Fan Shutoff: -30.0F Entire unit will shut off when outside
temperature drops below this value after
the delay period.
Delay: 0300s
SUPPLY HEAT OUT
Stage #1 Set: Stage
#2 Set:
080F 100F Setpoint for optional modulated afterheat
leaving air temperature
SUPPLY HEAT OVERRIDES
Heat 1 Diff: 100F When outside temp is ≤SPACE SET
POINT temp - this value, stage 1 heat will
energize
Override Set: 060F Setpoint for optional modulated afterheat
leaving air temperature when operaiing in
this override mode
OR Off Diff: 03F Deadband value to de-energize outside
temperature heating override.
SUPPLY HEAT OVERRIDES
Heat 2 Diff: 100F When outside temp is ≤SPACE SET
POINT temp - this value, stage 1 heat will
energize
Override Set: 070F Setpoint for optional modulated afterheat
leaving air temperature when operaiing in
this override mode
OR Off Diff: 03F Deadband value to de-energize outside
temperature heating override.
CONTROL SETUP Set for temperature or humidity control
priority
Priority: Humidity (Temperature) Humidity Humidity: When DH is called for, the
desiccant wheel will run.
Temperature: If cooling is called for, only
the compressors will run. The wheel will
shut off even if DH is called for.
SERVICE SETTINGS Setpoint Function
OUTSIDE AIR TEMP
Current: XX.X btu/lb
Comp A Set:
Comp B Set: 045.0
065.0
Compressors are not allowed to energize
when the ambient temperature drops to
these values respectively

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WHEEL CLEAN CYCLE This energizes the wheel motor and react
fan to clean the wheel during long periods
of off time
Cycle Delay: 150 hrs Clean cycle will run when supply fan runs
for this period of time without DH on
Clean Time: 020 min Length of time for clean cycle
SENSOR FAILURE ALARM Sensor failure alarm is enabled or disabled
by these settings. When sensor alarm is
disabled, sensor functions as
Disc Pres A: ENABLED normal but will not shut unit off when the
microprocessor senses a sensor failure.
This feature may be used to get a unit
Suct Pres A: ENABLED running temporarily when a non-essential
sensor failure occurrs.
SENSOR FAILURE ALARM
Disc Pres B: ENABLED
Suct Pres B: ENABLED
SENSOR FAILURE ALARM
Out Temp: ENABLED
Out Humid: ENABLED
SENSOR FAILURE ALARM
Heat Temp: ENABLED
Leav Temp: ENABLED
Post C Temp: ENABLED
PRESSURE OVERRIDE
Fans run at 100%
Setpoint = 320 psi
Run Time = 060 sec
SUPERVISOR SETUP
Ident: 00001 Must be set for either a cell phone modem
or a BMS communicating system. Call
factory for number
Baudrate: 19200 19200 for a cell phone modem. As
required for a BMS communicating
system.
Protocol: LOCAL Sets protocol for Serial Card: LOCAL for
I/O or Bacnet; KYOCERA for cell phone;
MODBUS; LONWORKS; REMOTE as
applicable
FACTORY SETTINGS Setpoint Min On Min Off Function
REACTIVATION FAN OUT:
Currently: Set
Point: No DH
Set:
XXX psi
444 psi 340
psi
Setpoint for
discharge pressure
for reactivation
compressor
REACTIVATION FAN OUT: Variables to adjust
modulation response
of the
condenser/react fan
Band: 095 psi Increasing this
number widens the
response band

14
Int Time: 950 sec Increasing this
number makes the
response slower
(prevents overshoot)
Deriv Time 12 sec Increasing this
number makes the
response faster
SUPPLY HEAT OUT Variables to adjust
modulation response
of the
condenser/react fan
Band: 05 F Increasing this
number widens the
response band
Int Time: 600 sec Increasing this
number makes the
response slower
(prevents overshoot)
MINIMUM ON/OFF TIMES
Sup Fan: 20sec 00sec Sets minimum on and
off times for the
supply fan
Comp A: 03min 05min Sets minimum on and
off times for
compressor A
MINIMUM ON/OFF TIMES
Wheel: 02min 01min Sets minimum on and
off times for the
desiccant wheel
Comp B: 03min 05min Sets minimum on and
off times for
compressor B
MINIMUM ON/OFF TIMES
Con Fan: 60sec 00sec Sets minimum on and
off times for the
condenser fan
Rea Fan: 20sec 00sec Sets minimum on and
off times for the
reactivation fan
INITIAL DELAY TIMES
Supply Fan: 0000 s Initial delays when
microprocessor is
powered on
Compressor A: 0000 s
INITIAL DELAY TIMES
Wheel: 0000 s
Compressor B: 05 min
INITIAL DELAY TIMES
React Fan: 0000 s
COMPRESSOR A RANGES
4mA 20mA Adjust to min and
max

15
Suct: 000 to 650 psi pressure range of
gauge
Disc: 000 to 650 psi
COMPRESSOR SET POINT
HIGH DISCHARGE PRESS
Shutoff: 600 psi Compressor will lock
out at this pressure
COMPRESSOR SET POINT
LOW SUCTION PRESS
Shutoff: 025 psi Compressor will lock
out if suction drops to
this pressure
COMP A -- CYCLE OFF LOW TEMPERATURE
Setpoint: 034.0 F Cycles the
compressor off when
the coil LAT drops to
this value
Delay: 330 s Delay for the above
function
COMP A -- CYCLE OFF LOW PRESSURE
Setpoint: 090 psi Cycles the
compressor off when
the suction press
drops to this value
Delay: 330 s Delay for the above
function
COMP B -- CYCLE OFF LOW TEMPERATURE
Setpoint: 034.0 F Cycles the
compressor off when
the coil LAT drops to
this value
Delay: 180 s Delay for the above
function
COMP B -- CYCLE OFF LOW PRESSURE
Setpoint: 110 psi Cycles the
compressor off when
the suction press
drops to this value
Delay: 180 s Delay for the above
function
COMP B --- CYCLE ON HIGH SUCTION PRESSURE
Set Point: 156 psi When compressor A
suction pressure
rises to this setpoint,
compressor B will
energize for its
minimum on time
after the delay
Delay: 0060s
COMP B -- CYCLE ON MIN SUCTION PRESS
Setpoint: 128 psi Compressor B will
not cycle on if suction
pressure is less than
or equal to this value

16
PRE/POST WHEEL ALARM
Differential: 05.0 F Sets minimum
differential between
desiccant wheel
entering and leaving
Delay: 030 min temperature to insure
wheel is turning (after
associated delay)
PRESSURE ALARMS
Low Diff: 075 psi Compressor will lock
out if diff between
suction and
discharge pressure is
Delay: 300 sec less than this amount
(after associated
delay)
VFD SETTINGS
VFD Reset: 120 sec When VFD reset is
initiated, this delay is
set to allow fans to
stop
Retry Delay: 030 min The pCO2 will wait
this period of time,
reset the VFD and
restart the unit
Retriew Til Fail: 04 The pCO2 will retry
this many times
before locking out
MISC SETTINGS
Manl Mode Del: 005 min Any manual modes
will be reset after this
delay
Relay 10: Liquid Line (Coil Bypass) Liquid Line Set "Liquid Line" on
units without coil
bypass damper
Dampers Del: 010 min Delay for bypass
dampers to open
(units with bypass
dampers only)
MISC SETTINGS
Fan Ops: STANDARD (ENERGY SAVE) STANDARD
Location OUTDOOR Selecting INDOOR
will not allow the
compressors to
alternate lead
Altitude: 0000 ft Adjusts calculated
ambient grain level
based on this altitude
value
SET PASSWORDS
LEVEL 01: 0001 Password (number)
for user access
LEVEL 02: 0002 Password (number)
for service access

17
LEVEL 03: 0003 Password (number)
for factory access
FACTORY SETTINGS
Model Num: HCUb410 Set to HCU model
Control Method: STD STD for I/O control
BMS for
communicating
control
4.5 SHUT DOWN
De-energizing output 1 on the CONTROLLER will shut the unit down.
4.6 ADJUSTING SUPPLY AIRFLOW
The supply airflow is adjusted by moving the direct drive supply fan closer to or farther away from the inlet
cone. Maximum airflow is attained when the inlet cone is just inside the blower wheel inlet. Moving the
motor/blower wheel away from the inlet cone reduces the airflow.
4.7 CONDENSER AND REACTIVATION FAN CONTROL
The reactivation fan is controlled by 2 VFD (variable frequency drive) and the condenser fans are
controlled in tandem by 3 VFD. Each VFD receives a 0 – 10 volt DC analog signal from the
microprocessor to control the speed of the fan to maintain a constant discharge pressure of 444 psig
during dehumidification mode and 340 psig during cooling-only mode. 2 VFD (reactivation fan) will
modulate from 50% minimum to 100%. 3 VFD (condenser fans) will energize and modulate from 20% up
to 100% as required. The purpose of the 444 psig discharge pressure during dehumidification mode is to
maintain sufficient condenser coil leaving air temperature for reactivation. At higher ambient
temperatures, it is normal for the discharge pressure to increase above these set points. See Appendix C
for VFD settings.

18
5 Maintenance
Note: This unit contains R410a refrigerant. Use only R410a refrigerant and POE oil.
This section includes some suggested maintenance requirements for this unit. This information is offered
as a guide, but your system may require more frequent maintenance. For example, if your unit is used in
a very dusty atmosphere, you should replace the air filters more often. Use these suggested schedules
as a starting point, and modify them to suit your own installation.
Munters dehumidifiers are designed to be very rugged and reliable. In fact, they have the lightest
maintenance requirements in the industry. However, this does not mean you can skip the maintenance
completely. Poor maintenance can result in poor performance, increased downtime and additional
operating costs.
Munters strongly recommends that you follow a comprehensive maintenance program. This program
should include not only the dehumidifier, but any support systems involved in the dehumidification
system.
5.1 QUICK MAINTENANCE CHECK
As the unit operates, make routine checks of these two basic functions:
• The supply air fan should be running whenever the controller is calling for “FAN” to be on.
• Turn on power to the unit and allow it to operate normally for about 30 minutes. (This will allow
time for the temperatures inside the unit to stabilize.) You should run this test at a time of day
when the HCU needs to run dehumidification. Using a simple probe thermometer, check the
temperatures leaving (LAT) the cooling coil, desiccant wheel, and condenser coil. The cooling
coil LAT should be 15 to 30 degrees F cooler than ambient. The wheel LAT should be 10 to 15
degrees F warmer than the coil LAT. The condenser coil LAT should be at least 112 degrees F.
5.2 SUGGESTED MAINTENANCE SCHEDULE
The following table lists the recommended maintenance schedule for this unit. For detailed instructions
on each procedure, see the sections that follow.
EVERY 30 DAYS
Check this Location
Inspect the ductwork. Supply air outlet (See Sect. 5.3)
Replace the air filters. As labeled (See Sect. 5.4)
ANNUALLY
Check this Location
Inspect the seals around the Both faces of the HoneyCombe® wheel
HoneyCombe®wheel.
(See Sect. 5.5)
Check the fans. Supply fan (See Sect. 5.6)
Reactivation fan
Condenser fan
Inspect the wheel drive motor. Cassette access panel or door
(See Sect. 5.7)
Inspect the roller wheels. Cassette access panel or door (See Sect. 5.8)
Inspect the electronic controls. Control panel (See Sect. 5.9)