1. A.R.T.
Munters (Amesbury) Technology Training - Dana Eldredge - Technical Support Technician

2. Maintenance
Maintenance for Munters dehumidifiers and systems is kept simple to minimize demands on facility maintenance personnel.

3. Maintenance Munters Recommended Maintenance Schedule
Munters has established baseline recommendations for periodic maintenance on the Honeycombe Dehumidifiers. Each Operation and Maintenance Manual (O&M) outlines these recommendations and procedures.
It is important to note that these recommendations are offered as a starting point and that the frequency of each maintenance procedure should be adjusted to suit your application. For example a unit in a pristine clean pharmaceutical installation may require filter changes no more frequently than once every 6 months, while a similar machine on a construction site may require the same filters be changed every two or three days.

4. Items are listed in order from most frequent to least frequent
Maintenance
Munters Recommended Maintenance Schedule
Items are listed in order from most frequent to least frequent
Every 1-7 Days
Check This
Location
Airflows
Process and Reactivation
Manometers for proper values
Rotation
Desiccant wheel turns 6-9 revolutions per hour
(once 6-8 min)
Temperatures
Reactivation outlet 120°F-130°F
Process inlet, design precool temp or lower

5. Munters Recommended Maintenance Schedule
Every 30 Days
Check This
Location
*Clean the air filters
Inlet for reactivation air Inlet for process air
*Inspect the seals around the Honeycombe® wheel
Both sides of the Honeycombe wheel
*Inspect the Honeycombe® wheel
Behind access panel, center of unit.
Check the temperature at the reactivation outlet
Outlet for reactivation air
* Frequency of these inspections can be stretched out over longer periods, depending upon the applications and harshness of the environment.

6. Munters Recommended Maintenance Schedule
Every 30 Days
Check This
Location
Check all ductwork
Inlet and outlet for process air for leaks. Leaks in the process duct work can adversely affect performance. Inlet and outlet for reactivation air
Units with steam reactivation
Check the steam piping
Steam supply lines and steam coil
Leaks, blocked strainers/traps

7. Munters Recommended Maintenance Schedule
Every 60 Days
Check This
Location
Inspect the blower fans
Blower for process air
Tightness of all fasteners and set screws.
Bearing lubrication
Inspect the electric controls
Check ALL electrical connections for tightness. Both power wiring and control wiring terminals
Inspect the wheel drive motor and belt
Check for signs of belt slippage or wear

8. Munters Recommended Maintenance Schedule
Every 60 Days
Check This
Location
Units with Indirect-Fired Gas Reactivation only:
Inspect for heat exchanger leaks
Visual inspection of heat exchanger
Inspect for corrosion of the drip tray
Below each gas heater

9. Munters Recommended Maintenance Schedule
Every 6 Months
Check This
Location
Inspect the roller wheels
Inside the desiccant wheel compartment. Excessive wear and play
Every 12 Months
Check This
Location
Units with Indirect-Fired Gas Reactivation only:
Wire brush exchanger to remove any rust. Signs of soot in the heat exchanger should be further investigated
From the top of each burner

10. Munters Recommended Maintenance Schedule
Every 12 Months
Check This
Location
Clean or replace burner pilot
Near each main burner. Clean with fine wire brush. Replace if corroded.
Inspect the pilot supply line for corrosion
Near each main burner.
Units with Indirect-Fired Gas Reactivation only:
Change the flame rod sensor
In the burner
Check the spark plug gap. Should be 7/64”

11. Maintenance
The following provides an overview of the maintenance items to be performed. Again the frequency should be adjusted to suit the application. Details of the actual procedures are given in the Operation and Maintenance Manual of each machine.
The items shown, are in general order of frequency. No timeframes are given, just the most frequent to the least frequent items.

12. The Primary Items needed for proper operation of Munters dehumidifiers
Maintenance
The A.R.T. of Dehumidification
The Primary Items needed for proper operation
of Munters dehumidifiers
Process airflow should be at or below design levels Reactivation airflow should be at or can be slightly above design Steam may vary due to energy modulation
Airflows
Rotation
Whenever airflow is present, the desiccant wheel shall be turning
Temperatures
Reactivation outlet at 120°F (110°F -145°F)
Process inlet at or below design

13. Maintenance A.R.T. Airflows Rotation Temperatures Check Airflows
Process minihelic Reactivation minihelic Values should equal design
Check Reactivation
Temperature
120°F
Check Process inlet
Temperature
At or below design
Check Wheel Rotation
6-10 RPH

20. Maintenance Airflows Rotation Temperatures Precooler
Check “P-traps” for water
Prime as necessary

22. Filters Maintenance Optional 30% Fiberglass Reactivation Metal Mesh
Washable
Wash with mild detergent and water. No spray on filter coating.
Optional
30% Fiberglass
Remove and replace as required

29. Lubrication Maintenance
There are no lubrication requirements for units* unless equipped with belt drive blowers.
Lubricate belt drive blower bearings every 4000 hrs.
* Older units can be converted with newer parts (roller support wheels) to eliminate the lubrication requirement of those machines.

30. Belts Maintenance Belt Drive Blowers. Check tension and for cracks
Desiccant Wheel Drive Belts are all Kevlar Timing Belts requiring no maintenance

33. Munters Self Tensioning Drive Arrangement
Maintenance
Munters Self Tensioning Drive Arrangement
Drive Assembly
Drive Sheave
Desiccant Wheel Support Roller
Major Components
Desiccant Wheel
Self Tensioning Drive Setup

37. Munters Self Tensioning Drive Arrangement
Maintenance
Munters Self Tensioning Drive Arrangement
Proper operation of the Self Tensioning Drive relies on proper setup and belt installation.
Begin belt setup, by letting the drive hang down straight. When threading the belt onto the drive sheave and idler/belt guide, it is essential that the drive be pushed inwards to provide clearance for the belt.
NOTE: If you pull the drive towards you to install the belt, the drive will not work to turn the desiccant wheel. This is a self tensioning drive and the motor “walks” towards the access panel as it increases belt tension. With the drive held forward while installing the belt, the drive will decrease tension as it starts.
Incorrect (pulled)
Correct (pushed)
When placing the belt onto the drive the drive must be pushed in towards the center of the unit, not pulled outward

38. Munters Self Tensioning Drive Arrangement
Maintenance
Drive Belt
Correct
Munters Self Tensioning Drive Arrangement
Drive Belt
Incorrect
Counterclockwise rotation of drive sheave, causes motor assembly to “walk” the belt towards the access panel opening. As it does so, the belt length is short enough that the belt tension is increased by this action.
If the drive assembly is lifted towards the access panel opening prior to engaging the belt, the effect will be opposite. The belt will loose tension as the drive moves out towards the access panel.

39. Electrical Maintenance
Tighten Electrical Connections and terminals for both power wiring and control wiring. Check for signs of overheated connections.

44. Seals Maintenance Wheel Seals
Wheel seals should be inspected every 6 months
Use .030” feeler gauge between wheel face and seal. Good seals will provide a moderate drag. No drag over more than 5% of seal area is cause for further inspection.

45. Seals Maintenance Visual inspection of seals:
Wear indicated by red area
Visual inspection of seals:
If black rulon surface
is worn through at areas other than joint connections, seals should be replaced.

46. Seals and Wheel Maintenance
Wheel Life is 7-10 years if maintained and operated properly Seal life is 3-5 years depending upon service duty Seals are replaced/sold in pairs.
Desiccant Wheel
Seal Kit

55. Honeycombe Wheel Maintenance The wheel should be inspected as follows:
Wheel Face:
Check for physical scarring of the wheel face. Minor imperfections may be repaired with RTV silicone or auto body filler.

56. Honeycombe Wheel Maintenance
Discoloring of the wheel face may indicate exposure to external particulate or excessive heat. A darkening of the reddish coloring is possibly due to excess heat. As long as there is no exposure of light grey material, there is no long term problem associated with this.

57. Honeycombe Wheel Maintenance
Cleaning: Visually inspect the wheel for blockage from dirt. Use drop light or strong flashlight on one side of wheel. Light should be visible on other side of wheel. If more than 15% of the total wheel face area is blocked, the wheel should be cleaned.

58. Honeycombe Wheel Maintenance Recommended Cleaning:
Use wet/dry vacuum with soft brush nozzle and thoroughly vacuum both wheel faces. Then re-inspect.
If blockage still exists: use dry, oil free compressed air (or nitrogen), with a maximum of 30 psig pressure to blow through the wheel in both directions. Do not place the air nozzle too close to the wheel face or deforming of the structure may occur. Blow out the wheel in both directions. Continue to do this until no evidence of dirt or dust emissions occurs.

59. Honeycombe Wheel Maintenance Recommended
If blockage still exists, and the wheel is a Lithium Chloride type, no further cleaning is possible. Replacement would be indicated if blockage still exists.
3. If wheel is Silica Gel it may be “rinsed” carefully with water. Do not pressure wash any of these wheels. Care should be taken when performing this procedure as the weight gain from the ingested water can be substantial.
After rinsing, use compressed air to blow out excessive water prior to reinstalling into the dehumidifier. Perform the wheel drying procedure before returning the unit to active operation.

65. Storage of Munters Desiccant Dehumidifiers
In general, the desiccant dehumidification systems are very resilient and can be stored for long periods without harm. There is however several preventative measures that you can take that will assure the maximum life for your unit. The desiccant wheel can absorb moisture even with the system off. Since a desiccant wheel has a capacity to hold several times its weight in moisture, it is best to store the wheel in a dry environment. It is not always necessary to remove the desiccant wheel to accomplish this.
If the dehumidifier is part of an air handling system, requiring air to be run through the dehumidification system even without it running, it would be best to run the dehumidifier in bypass mode, (providing the system is equipped with a face and bypass option). If the unit does not have the face and bypass option then the desiccant wheel should be removed from the unit and stored as mentioned in the “long term” storage procedure. In addition to removing the wheel the react inlet and outlet should be sealed from the process airstream.
This will prevent air from being drawn from the react inlet and outlet openings instead of the process inlet.
The face and bypass option is not to be confused with an internal, manual bypass that some systems are equipped with. This is a duct located directly under the desiccant wheel inside the basic unit. The internal bypass can be used as long as the process inlet and process outlet openings to the wheel are properly sealed.
Long term: storage can be defined as any unit out of service for a month or more.
Short term: storage can be defined as any time shorter a month.
Long term out of service: (out of service greater than 1 month)
The best option for storing an inactive system that will be out of service for more than 1 month is to simply protect the desiccant wheel from outside harm.
One can remove the desiccant wheel from the unit, (see the maintenance section of the O&M manual for proper wheel removal), shrink wrap it and put it in a box or crate. Storing the wheel in an environment of 50% RH or less is best but not necessary. The rest of the system should remain intact and the duct openings should be sealed to prevent foreign objects and weather from entering the system.
If it is possible to vapor seal the process inlet and outlet and the reactivation inlet and outlet openings, the desiccant wheel can remain in the unit. Vapor sealing can be accomplished with careful shrink wrapping of the 4 openings. The openings are comprised of the Process inlet and outlet and Reactivation inlet and outlet. This is the more desirable arrangement as it minimizes any potential handling damage to the desiccant wheel and seals. If this is not possible then removal of the desiccant wheel as describe above is the next best alternative.
In Short Term (out of service less than 1 month)
In some cases it may be necessary to leave the dehumidifier out of operation for shorter terms. If the equipment is to be left off for weeks, it is a good practice to prevent weathered air from entering the unit. Closing off or isolating any ducting that leads to the outside air should accomplish this. If the installed ductwork is so equipped, simply close any inlet and outlet dampers to the two airstreams. This can also be done by sealing off the duct intakes and discharges with vapor resistant material such as shrink wrap. Weathered air is typically reactivation in and out. Process inlet on some systems can also be outside air.

68. Munters Service Operations
Honeycomb® Wheel Inspection & Cleaning Procedure
Inspection: Visually inspect the wheel for blockage from contaminants. Use a drop light or strong flashlight to shine light through the Desiccant wheel. The light should be visible on the other side of the wheel as a soft white ball. If the inspection reveals that more than a 15% blockage exists, then the wheel should be cleaned per the instructions below. Inspect the wheel surface for signs of softening. Place your thumb against the surface of the wheel and press firmly.
The surface should be solid, without give. If the surface feels spongy, it is an indication that the wheel needs to be replaced. Also look for sections of the wheel face lifting away from the inner wheel media. The wheel media will have a “cotton candy” appearance to it. This is an indication that the wheel has come in contact with liquid water. The wheel should be replaced at this point. Look for signs of blackening on the wheel surface. This is an indication that the wheel has been exposed to temperatures in excess of 400ºF. Monitor the Reactivation discharge temperature and Reactivation manometer as these blacken surfaces pass through the Reactivation circuit. If the Reactivation airflow or Reactivation outlet temperature does not change as they pass through and the wheel is still reaching performance, the wheel does not require changing. If either the airflow or discharge temperatures are affected as the blackened areas pass through and the wheel is not maintaining performance, then the wheel should be replaced.
Cleaning: Use a shop vacuum with a soft brush nozzle to vacuum both wheel faces. Re-inspect the wheel using the inspection procedure. If the blockage still exists use a maximum 30 psig dry compressed air or dry Nitrogen, with a fan tip nozzle preferably, no closer than 12” from the wheel face to blow obstruction from wheel. Combine this with vacuuming for added effectiveness.
If blockage still exists and the wheel is a Lithium Chloride wheel then no further field cleaning is possible. The wheel may be returned to Munters for an inspection. A factory wash and Re-impregnation may be possible.
If the wheel is a Silica Gel, HPX or GTR it may be rinsed carefully with water. The desiccant wheel should be removed from the unit. It should be placed horizontally with its face surface blocked up off the floor as close to its outer rim as possible so as not to damage the wheel face. Care should be taken to support the wheel face while performing this function. A small amount of dish liquid may be incorporated as a degreaser if oils are suspected in the wheel.
Using a garden hose with the spray nozzle removed allow the water to flow over the wheel face gently rinsing the wheel media. The desiccant wheel should be
Munters Service Operations
79 Monroe Street
Amesbury MA 01913
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installed back into the dehumidifier after the rinsing process is complete. The desiccant wheel should be dried out soon after the washing process to minimize the stresses placed on the wheel structure by the substantial water weight increase. Once the wheel has been installed into the dehumidifier and after following all safety and lockout – tagout procedures, remove the Process blower fuses, and start the unit. On purge units consult the factory for wheel drying procedure. Run the unit in this manner until the reactivation outlet temperature reaches a consistent 120°F minimum and then for an additional 10 minutes after that. Once this has been achieved the dehumidifier can be powered down and the Process fuses installed back in the unit.
Munters Service Operations
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Amesbury MA 01913
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78. •

80. HCE Wheel Tightning Maintenance Recommended8 1
Due to the structural makeup of all HCE wheels, periodic inspection of sector tightness and run out is required. This should be conducted on an annual basis at a minimum.
If allowed to operate in a loose
condition, failure of the media sectors, ultimately requiring replacement, may result.
Refer to the Wheel Tightening Procedure in the Operation and Maintenance Manual for step by step instructions on wheel tightening. 7 2 6 3 5 4

86. Troubleshooting

87. Troubleshooting Fault Identification and Resolution
This section details troubleshooting of the dehumidifier faults.
If the machine you are working with has a fault enunciator or other means of specifying which fault the machine has shut down on, proceed to Chart 1.
If you need assistance determining which fault the machine has gone out on, proceed to Chart 2.
HC-150I and 300 units have their own charts, review Charts 3 & 4.

88. Fault Identification and Resolution
Chart 1
Troubleshooting
Fault Identification and Resolution
Low Reactivation Outlet Temperature Fault
Reason: Reactivation Outlet Temperature was below 110°F for 30 minutes or longer.
Possible Causes:
Failed Electric Heater Elements or fuses
Improper output from SSPC
Insufficient Steam Pressure, blocked traps or strainers
Improper operation of modulating steam damper (open for more heat, close for less heat.
Check TS03 switch calibration
Excessive Process Volume
Excessive Process inlet humidity
High process inlet temperature on precool units
Low gas pressure or failed pilot on gas units
Initial pull down of humidity may cause high loads on the dehumidifier resulting in Low temp faults Rest the unit up to two times is acceptable to overcome this.
Reason: Reactivation temperature between heater and desiccant wheel exceeded 325°F, or 350°F on gas fired units.
Reactivation Overheat Fault
Possible Causes:
Low Reactivation airflow. Check minihelics
Check for dirty of blocked filters
Check for closed dampers in reactivation airstream
Check for excessive gas pressure.
Check for corroded or distorted overheat switch (TS01) warp switch, located above heater elements.
Reset TS01 to 350°F on gas fired units.
Reason: The desiccant wheel did not prove rotation within a 10 minute period.
Wheel Rotation Fault
Possible Causes:
Is the desiccant wheel rotating once every 6-9 minutes?
Check for belt slippage
Check wheel cam/limit switch adjustment. Limit switch should click no more than half way up the cam
Failed drive motor.
Reason: One of the motors is drawing amperage above nameplate full load amperes.
Motor Overload Fault
Possible Causes:
Airflows above design may over amp blower motors, adjust as necessary
Incorrect voltage to motor.
Rapid cycling on/off of motor or unit may cause overload trip or fuse failure.
Single phasing either of the supply voltage or as a result of a blown fuse can cause trips.

89. Fault Identification and Resolution
Troubleshooting
Fault Identification and Resolution
Overheat Fault Temp exceeds 325°F
Low React Fault Temp < 110°F for 30 minutes
1 TS
3 TS
Heater
React
Motor Overload Fault Motor exceeds nameplate amperage
Rotation Fault Wheel doesn’t prove rotation <10 minutes
D/H
1 LS
Process

90. Unit has a Fault Condition
Chart 2
Troubleshooting
Fault Identification and Resolution
Use this chart if you need assistance identifying a fault condition
Unit has a Fault Condition
Determine the
Type of machine
Unit is an HC,
HCD or HCE
Unit is an IDS
Unit is an HC-150I,
150R, DEW300,
HC300 with push
buttons
Unit is and HC150I,
150R, DEW300
HC300 with Rotary
Selector Switch
CHART 4
Determine if unit has a PLC or not
CHART 1
Unit has a PLC
Unit has NO PLC
CHART 3

91. Fault Identification and Resolution
Chart 3
Troubleshooting
Fault Identification and Resolution
Use this chart if you need assistance identifying a fault condition on units without a PLC. This will be accomplished by a process of elimination.
To determine the source
of the
fault, follow this guide.
Rotation Fault is on a 10 minute timer
Low Reactivation Outlet Temperature is on a 30 minute timer
Overheat has no time delay
Remove timer relay
3TR (5TR) and
restart unit.
Fault Condition
does not repeat
See Chart 1
Low Reactivation
Outlet temperature
fault
Fault Condition
repeats itself.
Reinstall 3TR and
proceed
Fault Condition
does not repeat
See Chart 1
Rotation Fault
Fault Condition
does not repeat
See Chart 1
Reactivation
Overheat
fault
Remove the timer relay
labeled 2TR and
restart unit.

92. Fault Identification and Resolution
Chart 4
Troubleshooting
Fault Identification and Resolution
Use this chart if you are troubleshooting HC-150/300 units with round indicator lights and a rotary selector (On, Off, Auto) switch.
Unit runs and shuts
down
Unit lights the
Fault light
Unit does not light
The fault light
Unit is shutting down on Reactivation high temperature fault
Check the following:
Dirty or blocked reactivation inlet filters, ductwork (inlet or outlet).
Reactivation damper closed too much
Worn or torn desiccant wheel seals
Does unit run okay in manual? Unit may be cycling off on humidity Control.
Check unit circuit breaker and supply voltage to the machine.