Stulz DAH User manual

DAH
Ducted Air Humidier
Installation, Operation and Maintenance Manual
Ultrasonic Humidication
DAH Series
GEN2
Installation, Operation and Maintenance Manual
Energy Efficient Ultrasonic Humidifier

DAH Series GEN 2 Ultrasonic Humidifier IOM Manual
Notice
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equipment for which this manual is written may photocopy the contents of this manual for internal use
only. No part of this document may be photocopied, reproduced, or translated into another language for
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written consent of STULZ Air Technology Systems, Inc. (STULZ).
This document contains confidential and proprietary information of STULZ Air Technology Systems, Inc.
Distributing or photocopying this document for external distribution is in direct violation of U.S. copyright
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Unpublished — rights reserved under the copyright laws of the United States and of other countries.
Other brands and tradenames are trademarks of their respective owners.
Copyright 2019 by STULZ Air Technology Systems, Inc.
Printed in the United States of America.
All rights reserved.
STULZ Air Technology Systems, Inc.
1572 Tilco Drive
Frederick, MD 21704 USA
https://www.stulz-usa.com/en/

Series GEN 2 Ultrasonic Humidifier IOM Manual
Table of Contents
Energy Efficient Ultrasonic Humidifier ..................................................................................................... 1
Introduction.............................................................................................................................................. 1
Safety ................................................................................................................................................ 1
Safety Summary............................................................................................................................. 1
Specifications................................................................................................................................. 3
General Design..................................................................................................................................... 4
Main Parts ............................................................................................................................................ 4
Ultrasonic Nebulizer Unit ............................................................................................................... 4
Mist Outlet ...................................................................................................................................... 4
High Water Float Switch................................................................................................................. 4
Low Water Float Switch.................................................................................................................. 4
Water Fill Valve Solenoid ............................................................................................................... 4
Water Supply Valve ........................................................................................................................ 4
Water Supply Tubing ...................................................................................................................... 4
Drain and Overflow Assembly........................................................................................................ 4
Temperature Sensor ...................................................................................................................... 5
Solid State Relay ........................................................................................................................... 5
Level Controller.............................................................................................................................. 5
BoosterFan (Optional DAH-24/30 Only) ........................................................................................ 6
Mounting Rack (Optional) .............................................................................................................. 7
Installation ............................................................................................................................................... 8
Receiving the Equipment...................................................................................................................... 8
Site Preparation.................................................................................................................................... 8
Mounting and Placement....................................................................................................................... 10
Supply and Drain Piping ..................................................................................................................... 12
Main Power and Control Wiring ......................................................................................................... 13
Wire Sizing — Control Box to Humidifiers ................................................................................... 13
Connecting Humidifier(s) to Control Box...................................................................................... 14
Single Humidifier.......................................................................................................................... 15
Multiple Humidifiers (Grouped) .................................................................................................... 15
Multiple Humidifiers/Optional Multi-Tier Mounting Rack (Grouped)............................................. 15
Operation............................................................................................................................................... 16
Purge the Water Line .......................................................................................................................... 16
Initial Operation Checklist................................................................................................................... 16
Operation Procedure .......................................................................................................................... 16
Precautions......................................................................................................................................... 17
Steps for Long Term Shutdown .......................................................................................................... 17
Maintenance .......................................................................................................................................... 18
Periodic General Maintenance ........................................................................................................... 18
General Maintenance................................................................................................................... 18
Maintenance Items and Tools ............................................................................................................. 19
Electrical Parts ............................................................................................................................. 20
Float Switches.............................................................................................................................. 21
Water Tank................................................................................................................................... 21
Water Supply Strainer/Flow Regulator......................................................................................... 21
Troubleshooting and Repair ............................................................................................................... 22
Common Repairs and Parts Replacement .................................................................................. 24
Temperature Sensor on Water Tank............................................................................................. 25
Replacing a Transducer ............................................................................................................... 25
Replacing a Nebulizer Print Plate ................................................................................................ 22
Water Solenoid Valves, Float Switches and Level Control Board................................................ 22
Fill Solenoid Valve........................................................................................................................ 22
Drain Solenoid Valve ................................................................................................................... 23

Series GEN 2 Ultrasonic Humidifier IOM Manual
Float Switches.............................................................................................................................. 23
Level Control Board ..................................................................................................................... 23
Product Support .................................................................................................................................... 24
Technical Support............................................................................................................................... 24
Obtaining Warranty Parts ................................................................................................................... 24
Obtaining Spare and Replacement Parts.............................................................................................. 26
Drawings................................................................................................................................................ 27
Unit Component Layout Drawing of Humidifier (Exploded View)....................................................... 27
DAH-04/16 - Typical Wiring Diagram for Modbus Version .......................................................... 28
DAH-04/16 - Typical Wiring Diagram for Stand-Alone Version ................................................... 29
DAH-24/30 - Typical Wiring Diagram for Stand-Alone Version ................................................... 30
DAH-24/30 - Typical Wiring Diagram for Stand-Alone Version ................................................... 31
Figures
Figure 1. Ultrasonic Humidifier- Model DAH-16 ........................................................................................ 2
Figure 2. Booster Fan Assembly ............................................................................................................... 6
Figure 3. Humidifier Mounting Rack (Front View, Shown with Five Humidifiers) ...................................... 7
Figure 4. Ultrasonic Humidifier Mounting................................................................................................. 10
Figure 5. Duct Mounting — Vertical Arrangement ................................................................................... 11
Figure 6. Duct Mounting — Cascade Arrangement................................................................................. 11
Figure 7. Water Supply and Drain ........................................................................................................... 12
Figure 8. Power and Control Wiring......................................................................................................... 13

Series GEN 2 Ultrasonic Humidifier IOM Manual
Nomenclature
DRH-04-S
DRH DAH S Number of
Transducers
Ducted Air
Humidifier
Ducted Air
Humidifier
(Blank) =
Ultra Series
Control
S = Stand
Alone
04, 08, 12, 16,
24, 30

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Series GEN 2 Ultrasonic Humidifier IOM Manual
Introduction
Recognized as a world leader, STULZ Air Technology Systems, Inc. (STULZ) Ultrasonic humidifiers are
designed and manufactured with the highest quality craftsmanship using the finest materials available.
Your ultrasonic humidification system will provide years of trouble free service if installed and maintained
in accordance with this manual.
Damage to the unit from improper installation, operation or maintenance is not covered by the warranty.
This manual contains information for installation, operation, maintenance, troubleshooting and repair.
Study the instructions contained in this manual. They must be followed to avoid difficulties. 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. Due to technological advancements, components are subject to
change without notice.
DAH Series Ultrasonic Humidifiers are designed for use with a central air handler unit (AHU). They may
be rack mounted in an AHU or mounted in the air distribution ductwork.
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
STULZ uses 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.
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 application.
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 guidelines followed by warnings and cautions applicable throughout
the manual.
Prior to performing any installation, operation, maintenance or troubleshooting procedure read and
understand all instructions, recommendations and guidelines contained within 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.
CAUTIONS
This unit must be installed according to local and national electric codes.
All maintenance and/or repairs must be performed by a qualified technician. All personnel working 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.

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Series GEN 2 Ultrasonic Humidifier IOM Manual
NOTES
Wiring terminations may become loose during transit of the equipment therefore; verify all wiring
terminations are secure prior to operation.
Do not attempt to make repairs without the proper tools.
NOTE: STULZ offers no warranty protection on humidification systems using controls not provided by STULZ.
CAUTIONS
It is essential that De-ionized (DI) or Reverse Osmosis (RO) water be used as the supply water source to
maintain full warranty coverage. 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.
Observe the unit for water leakage. A short circuit could occur if the humidifier is splashed with water
while operating.
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 as this may damage internal parts.
Drain the water in the tank for sanitary reasons when humidifier is turned is off for more than 3 days.
Figure 1. Ultrasonic Humidifier Model DAH-16

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Series GEN 2 Ultrasonic Humidifier IOM Manual
Specifications
Type DAH Series Ultrasonic Humidifier Model
Model DAH-04 DAH-08 DAH-012 DAH-16 DAH-24 DAH-30
Nebulizing capacity, lb/h 5.3 10.6 15.8 21.1 30.8 39.6
Qty. of ultrasonic nebulizers/unit 4812 16 24 30
Power source, VDC 48
Rated power consumption, W 125 246 366 486 726 906
Weight, lb 15.4 21.7 28.0 34.3 37.5 44.1
Electrical Characteristics
Allowable voltage range, VDC 47-51
Insulation resistance, MOhms 100 or more (excluding solid-state components).
Dielectric voltage withstand Operational when 1500 VAC is applied for 1 minute (excluding solid-state
components).
Operating conditions
Ambient working conditions 34 °F to 122 °F; 90%RH or less.
Water supply quality DI or RO water. Water conductance <5 microsiemens purity.
Water supply pressure, psi 30 to 75
Water supply temperature, °F 40 to 104
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 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.

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Series GEN 2 Ultrasonic Humidifier IOM Manual
General Design
The DAH Series Ultrasonic humidifier directly atomizes water with high frequency mechanical oscillation,
producing a fine mist to be delivered into the room by the laminar airflow of an AHU fan.
DAH humidifiers may be mounted in the air distribution ductwork or rack mounted in the AHU. For large
AHU applications with low AHU air velocity, ultrasonic humidifier models DAH-24 and DAH-30 may be
equipped with an optional booster fan to propel the mist out.
The humidifier uses high frequency nebulizers to produce ultrasonic waves 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 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 Outlet
Directs mist out of the humidifier and eliminates larger mist particles so the humidifier only introduces fine
mist into the air stream.
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.
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 SupplyValve
NOTE: This is to be provided by the user.
A valve must be installed upstream from the humidifier for service and maintenance. The valve must be
rated for use with DI water.
Water SupplyTubing
NOTE:Thus user must provide the water supply tubing.
Water supply tubing must be provided to connect the water supply to the water strainer/flow regulator in
the back 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

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Series GEN 2 Ultrasonic Humidifier IOM Manual
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
diverted 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
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 must be present at all times to allow the Level Controller microprocessor to monitor the inputs
and control the outputs.
The microprocessor monitors the On and Off command from either the Modbus or the input dry contact
(depending on which model was purchased). If commanded on, the microprocessor checks the Low
Water Float Switch and the High Water Float Switch. If the water is too low, the microprocessor turns on
the Water Fill Valve Solenoid and monitors the Float Switches.
When the water level is above the low water level, the fan is turned on. When the water level is above the
high water level, the Water Fill Valve Solenoid is turned off and the Solid State Relay is turned on. When
the water level falls below the high water level, the microprocessor turns the Water Fill Valve Solenoid on
again to maintain optimal water level. When the on/off command is removed, the Solid State Relay is
turned off and, after a few seconds time delay to eliminate the remaining mist out of the humidifier, the
Fan is turned off.
Proportional control is accomplished by the microprocessor monitoring the proportional signal from the
Modbus or proportional input (depending on which model was purchased). When the proportional signal
is greater than 10% of the maximum input, the microprocessor will turn the Solid State Relay on and off in
a pulse-width modulation control. The period of the pulse width is 1 seconds.
For 10% control, the Solid State Relay is turned on for 0.1 seconds and off for 0.9 seconds. The on time
increases as the input approaches 100%. At 100%, the Solid State Relay is on continuously.
Safety control is built into the microprocessor. The voltage applied to the transducer controls the amount
of mist produced. Too high a voltage can cause damage to the transducer and too low a voltage prevents
mist from being formed. The microprocessor monitors the 48VDC to be with a range of voltages. If the
voltage is out of range, the microprocessor will not energize the Solid State Relay.
If the temperature of the tank rises too high, the microprocessor will turn off the Solid State Relay. If the
temperature approaches freezing, the microprocessor will turn off the Solid State Relay and the fan, and
then drain the tank to prevent damage from freezing water. When the temperature returns to a safe level,
normal operation is resumed.
A low level alarm is annunciated when the microprocessor sees the Low Level Float Switch indicate low
water after the tank has been filled. A fill alarm is annunciated when the High Water Float Switch does
not indicate the water level has been achieved after a predetermined amount of time.
A transducer alarm is annunciated if the transducers have been energized and no water is used in a
predetermined time (indicating no transducer is functioning). For the Modbus version of the Level