Stulz DRH User manual

DRH
Direct Room Humidier
Installation, Operation and Maintenance Manual
Ultrasonic Humidication
DRH Series
GEN2
Energy Efficient Ultrasonic Humidifier
Models: DRH 04, 06, 08, 16
Installation, Operation and Maintenance Manual

IOM
Notice
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Copyright 2019 by STULZ Air Technology Systems, Inc. Printed in the United States of
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All rights reserved.
STULZ Air Technology Systems, Inc.
1572 Tilco Drive
Frederick, MD 21704 USA
https://www.stulz-usa.com/en/
®

DRH Series GEN2 Ultrasonic Humidifier IOM Manual
Table of Contents
Introduction ......................................................................................................................................................................... 6
Safety ...........................................................................................................................................................................................6
Safety Summary ..................................................................................................................................................... 6
Specifications ..................................................................................................................................................................................8
General Design................................................................................................................................................................................9
Main Parts .........................................................................................................................................................................................9
Ultrasonic Nebulizer Unit .................................................................................................................................... 9
Mist Guide................................................................................................................................................................. 9
High Water Float Switch...................................................................................................................................... 9
Low Water Float Switch....................................................................................................................................... 9
Fan ..................................................................................................................................................................... 9
Air Filter ..................................................................................................................................................................... 9
Water Fill Valve Solenoid.................................................................................................................................. 10
Water Supply Valve............................................................................................................................................. 10
Water Supply Tubing.......................................................................................................................................... 10
Drain and Overflow Assembly ........................................................................................................................ 10
Temperature Sensor.......................................................................................................................................... 10
Solid State Relay ................................................................................................................................................. 10
Level Controller.................................................................................................................................................... 10
Installation......................................................................................................................................................................... 12
Receiving the Equipment ..........................................................................................................................................................12
Site Preparation............................................................................................................................................................................13
Mounting/Placement .................................................................................................................................................................14
Supply and Drain Piping.............................................................................................................................................................14
Main Power and Control Wiring..............................................................................................................................................16
Wire Sizing Control Box to Humidifiers..................................................................................................................................17
Connecting Humidifier(s) to ControlBox....................................................................................................... 17
Single Humidifier................................................................................................................................................. 17
Multiple Humidifiers (Grouped)...................................................................................................................... 18
Operation........................................................................................................................................................................... 19
Purge the Water Line ..................................................................................................................................................................19
Initial Operation Checklist .........................................................................................................................................................19
Procedure for Operation............................................................................................................................................................19
Precautions....................................................................................................................................................................................20
Steps for Long Term Shutdown ...............................................................................................................................................20
Maintenance/Repairs................................................................................................................................................... 21
Periodic General Maintenance.................................................................................................................................................21
Air Filter .................................................................................................................................................................. 23
Water Supply Strainer/Flow Regulator ...................................................................................................... 23
Float Switches...................................................................................................................................................... 24
Water Tank............................................................................................................................................................. 25
Mist Guides............................................................................................................................................................ 25
Troubleshooting and Repair .....................................................................................................................................................26

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Common Repairs/Parts Replacement ..................................................................................................................................28
Preparation for Repairs (Removal of Water Tank)................................................................................... 28
Reassembling....................................................................................................................................................... 28
Replacing the Temperature Sensor ............................................................................................................. 29
Temperature Sensor on Water Tank ............................................................................................................ 29
Replacing a Transducer .............................................................................................................................................................30
Replacing a Nebulizer Print Plate ................................................................................................................. 31
Water Solenoid Valves, Float Switches and Level..............................................................................................................31
Control Board ....................................................................................................................................................... 31
Fill Solenoid Valve............................................................................................................................................... 31
Float Switch .......................................................................................................................................................... 32
Level Control Board ........................................................................................................................................... 32
Drain Solenoid Valve .......................................................................................................................................... 32
Product Support ............................................................................................................................................................. 33
Technical Support........................................................................................................................................................................33
Obtaining Warranty Parts ..........................................................................................................................................................33
Obtaining Spare/Replacement Parts ..................................................................................................................... 34
Drawings............................................................................................................................................................................ 35
Layout Drawing of Humidifier (Covers Removed to Show Parts) ..................................................................................35
Electrical Circuit Diagrams........................................................................................................................................................36
Typical Wiring Diagram for Modbus Version............................................................................................. 36
Typical Wiring Diagram for Stand-Alone Version.................................................................................... 37
Figures
Figure 1. Ultrasonic Humidifier- Model DRH-06.......................................................................................................... 8
Figure 2. Installation of Humidifier.................................................................................................................................. 13
Figure 3. Locating the Humidifier.................................................................................................................................... 14
Figure 4. Piping Connections............................................................................................................................................ 15
Figure 5. Water Inlet Connector....................................................................................................................................... 16
Figure 6. Electrical Connections...................................................................................................................................... 17

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Nomenclature
DRH-04-S
DRH DAH S 04
Ducted Air
Humidifier
Ducted Air
Humidifier
Stand
Alone
Number of
Transducers

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Introduction
DRH Ultrasonic Humidifiers are designed and manufactured with the highest quality
craftsmanship using the finest materials available in the industry.It will provide years of
trouble free service if installed and maintained in accordance with this manual.
Spare parts are available from STULZ to ensure continuous operation. Using substitute
parts or bypassing electrical components in order to continue operation is not
recommended and will VOID THE WARRANTY. Damage to the unit from improper
installation, operation or maintenance is not covered by thewarranty.
Due to technological advancements, components are subject to change without notice.
Each unit is designed as a stand-alone direct room humidifier. Any use beyond this is
deemed to be not intended. STULZ is not liable for any damage resulting from improper
use. The system is designed to be installed indoors unless otherwise noted on the
equipment nameplate.
Safety
We use NOTES along with CAUTION and WARNING symbols throughout this manual to
draw your attention to important operational and safety information.
A bold text NOTE marks a short message in the information to alert you to an important
detail.
A bold text CAUTION safety alert appears with information that is important for
protecting your equipment and performance. Be especially careful to read and follow all
cautions that apply to your application.
A bold text WARNING safety alert appears with information that is important for
protecting you from harm and the equipment from damage. Pay very close attention to all
warnings that apply to your ap- plication.
A safety alert symbol accompanies a general WARNING or CAUTION safety
statement. A safety alert symbol accompanies an electrical shock hazard WARNING
or CAUTION safety statement.
Safety Summary
The following statements are general safety guidelines. They are followed by warnings
and cautions. Prior to performing any installation, operation, maintenance or
troubleshooting procedure read and understand all instructions, recommendations and
guidelines in this manual.
WARNING
High voltage is used in the operation of this equipment. Death on contact may result if
personnel fail to observe safety precautions.

DRH Series GEN2 Ultrasonic Humidifier IOM Manual
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CAUTIONS
This unit must be installed according to local and national electric codes. All maintenance and
repairs must be per- formed by a qualified technician. All person networking on or near
equipment should be familiar with hazards associated with electrical maintenance.
Always turn off the main power and unplug the unit before beginning work on the equipment.
NOTES
Wiring terminations may become loose during transit of the equipment therefore, so verify all
wiring terminations are secure prior to operation. Do not attempt to make repairs without the
proper tools. STULZ offers no warranty protection on humidification systems using controls
that are not provided by STULZ.
CAUTIONS
It is essential that Deionized (DI) or Reverse Osmosis (RO) water be used as the supply water
source to maintain full warranty cover- age. The use of untreated water will VOID THE
WARRANTY.
Use only non-corrosive stainless steel or poly tubing rated for use with DI water to supply the
humidifier.
Provide a drain with an air gap per local and national plumbing codes.
Never block the mist outlet or the opening of the air inlet. The humidifier may be filled with the
condensed mist and electrical shorts may result.
Never attempt to remove the mist guide cover and/or the mist blow tubes while the humidifier
is operating, or electrical shorts may result.
If there is a risk of supply water freezing, pipe insulation should be provided.
Never apply power when the humidifier is overturned or upside down. Damage to the
ultrasonic nebulizer unit or transducer may result.
Never drop the humidifier or apply hard shock to it. It may damage internal parts.
Drain the water in the tank for sanitary reasons when humidifier is turned is off for more than 3
days.
Observe the unit for water leakage. A short circuit could occur if the humidifier is splashed
with water while operating.

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Figure 1. Ultrasonic Humidifier- Model DRH-06
Specifications
Type
DRH Series Ultrasonic Humidifier
Model
DRH-04
DRH-06
DRH-08
DRH-16
Nebulizing capacity (lb/h) 4.4 6.6 8.8 17.6
Qty. of Ultrasonic nebulizers/unit 4 6 8 16
Power source 48VDC
Rated power consumption (W) 134 195 256 505
Weight (lb) 19.8 24.3 30.9 50.7
Electrical Characteristics
Allowable voltage range 47-51VDC
Insulation resistance 100 M.Ohms or more (excluding solid-state components).
Dielectric voltage withstand Operational when 1500VACisapplied for1 minute (excluding solid-state components).
Operating Conditions
Ambient working conditions 34 to 122°F; 90%RH or less.
Water supply quality DI or RO water. Water conductance <5 microsiemens purity.
Water supply pressure 30 to 75 psi
Water supply temperature 40°F to 104°F
These parts must be provided by the user:
DI or RO supply water, Water supply valve, Water supply tubing (1/4”
stainless steel or poly tubing rated for DI water), power supply wiring and control wiring to the control box.
1. Calcium, magnesium or other agents that may be contained in the supply water are atomized into
the air together with the mist and may form white powders after the water has evaporated. To avoid
this, always use DI or RO supply water.
2. The nebulizing capacity of the transducer in the ultrasonic nebulizer unit decreases gradually with

DRH Series GEN2 Ultrasonic Humidifier IOM Manual
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use. It should usually be exchanged after about 10,000 to 15,000 hours of operation, (depending
on water quality and suitable voltage), although the unit may continue to run as long as its effective
capacity meets the particular requirements.
3. To ensure full warranty coverage, the input voltage to the humidifier must not exceed 51VDC. If the
input voltage exceeds 51VDC, damage to the transducers and print plates will result.
General Design
The DRH Ultrasonic Humidifier directly atomizes water, producing a fine mist. The humidifier
incorporates high frequency nebulizers to produce ultrasonic waves, a fan to propel the mist
out, and an automatic water supply mechanism to maintain the supply water at a constant
level. When conducting routine maintenance, it is important to clean the air filter and water
tank because it significantly affects the humidifying capacity and life of the ultrasonic
nebulizers.
Main Parts
Ultrasonic Nebulizer Unit
This consists of a modular assembly located in the bottom of the water tank incorporating a
1.6 Mhz power oscillator on and a piezoelectric transducer. The transducer vibrates at that
frequency,developing ultrasonic columnar waves in the water and producing a fine mist
above that column.
Mist Guide
The mist guide carries the mist off the top of the columnar wave and directs it up and out of
the humidifier.
High Water Float Switch
For maximum atomization, it is essential the water level in the tank be constantly maintained.
The High Water Float Switch is an input to the Level Controller. It is open when the water level
is below the optimal level and is closed when the water level reaches the maximum level.
Low Water Float Switch
Operating the humidifier when the water level is below the top of the transducers will damage
the Ultrasonic Nebulizer Unit. The Low Water Float Switch is an input to the Level Controller. It
is open when the water level is near an unsafe level and is closed when the water level is at a
minimal level.
Fan
The 24VDC fan or fans both lightly pressurizes the air above the water to provide a path for
the mist to pass through the Mist Tubes and provides a sheet of air to carry the mist away from
the humidifier into the room. The fan is controlled by the Level Controller.
Air Filter
The Air Filter removes coarse dust from the air and prevents the humidifier water tank from

DRH Series GEN2 Ultrasonic Humidifier IOM Manual
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becoming dirty which would affect the mist output.
Water Fill Valve Solenoid
The Water Fill Valve Solenoid is a 24VDC solenoid that allows water from the water supply to
enter into the tank when energized by the Level Controller. There is an orifice to restrict the
flow of water.
Water Supply Valve
NOTE: The user must provide the water supply valve.
A valve must be installed upstream from the humidifier for service and maintenance. The valve
must be rated for use with DI water.
Water Supply Tubing
NOTE: The user must provide the water supply tubing.
Water supply tubing must be provided to connect the water supply to the water strainer/flow
regulator on the end of the unit. The strainer/flow regulator is equipped with a 90° swiveling,
¼” push-to-connect fitting. Use ¼” stainless steel or poly tubing rated for use with DI water.
Drain and Overflow Assembly
The Drain and Overflow Assembly contains a 24VDC drain solenoid valve, an overflow pipe
and a drain outlet. The drain valve solenoid is controlled by the Level Controller to drain water
from the tank via the drain outlet.
If the water level in the tank exceeds the height of the overflow pipe, the excess water is di-
verted to the drain outlet. The drain outlet pipe is 1/8” MPT and ships with a stainless steel
cap.
Temperature Sensor
The temperature sensor monitors the temperature of the tank and is read by the Level
Controller which prevents overheating and freeze protection. Indication is read at the Level
Controller in the humidifier.
Solid State Relay
The 48VDC operating voltage for the Ultrasonic Nebulizer Units is switched on and off by a
solid state DC relay controlled by the Level Controller.
Level Controller
The Level Controller is a microprocessor based device located in the electric box that receives
inputs from sensors and other inputs and in turn controls the valves, fan and Ultrasonic
Nebulizer Units.
It consists of a DC-DC power supply to convert the 48VDC to 24VDC for the fans and
solenoids and a further reduction to 5VDC for the microprocessor, sensors, power switches
and either a Modbus interface to communicate with the Ultra-Series Control box or a simple
standalone input interface depending on which model humidifier was purchased. The 48VDC