Herrmidifier Herrtronic MD User Manual

Engineered Humidification Systems

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Herrtronic® MD Series

Installation, Operation, & Maintenance

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Installation, Operation, & Maintenance Manual

TABLE OF CONTENTS

SECTION I WARRANTY

Warranty ...............................................................................................................................................3

SECTION II UNIT OPERATION

Herrtronic MD: Basic Operation ............................................................................................................ 4

Types of Control ....................................................................................................................................5

SECTION III INSTALLATION INSTRUCTIONS

Allowable Operating Conditions ............................................................................................................6

Mounting ............................................................................................................................................... 6

Plumbing ............................................................................................................................................... 6

Supply Power ........................................................................................................................................7

Steam Distributor Pipes ........................................................................................................................ 8

Steam Distributoin for Ducted Systems ................................................................................................ 9

Controls ................................................................................................................................................10

Control Circuit Connections .................................................................................................................. 10

External Off Switch ...............................................................................................................................11

Remote Alarm Output ........................................................................................................................... 12

Unit Networking ....................................................................................................................................12

SECTION IV OPERATION INSTRUCTIONS

Operating Instructions ...........................................................................................................................13

Programming ........................................................................................................................................14

Start-up with Check List ........................................................................................................................ 16

Diagnostics ...........................................................................................................................................19

System Fault Conditions ....................................................................................................................... 20

Maintenance .........................................................................................................................................20

SECTION V TROUBLESHOOTING GUIDE

General Maintenance Notes ................................................................................................................. 22

Operating The Humidier Without External Controls ............................................................................ 22

Unit Detected Faults: (Red “Service” Light On) ....................................................................................24

Non-Fault Indicated Problems ..............................................................................................................25

Troubleshooting Without Unit-Detected Faults .....................................................................................27

Output / Input of Terminal Strips and Terminal Block ............................................................................ 28

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Herrtronic® MD Series

Installation, Operation, & Maintenance Manual

I. WARRANTY

Limited 2-Year Warranty

Seller warrants the equipment of its manufacturing to be free
from defects in workmanship and material for a period of 24
months after shipment or 24 months after initial commissioning,

whichever occurs rst. This warranty is limited, however, to the

repair or replacement of defective equipment, which is returned,
freight prepaid, to Seller’s factory.

This limited warranty does not apply to any part or component
that is damaged in transit or when handling, has been subject
to misuse, negligence or accident, has not been installed, oper­ated or serviced according to Seller’s instructions, or has been
operated beyond the factory-rated capacity or has been altered
in any way.

Seller’s liability is limited to replacement of defective parts or
components and does not include any cost of labor (including,
but not limited to, labor required to remove and/or reinstall any

defective part) other than Trion/Herrmidier factory labor.

Each of the Herrtronic series of steam generating humidiers

contains a plastic steam generating cylinder that is to be consid­ered a routinely disposable part to be changed at regular main­tenance intervals at the user’s expense. This steam generating

cylinder is not covered by this Warranty. If, after the rst instal­lation of your Herrtronic humidier, you feel the steam generat-

ing cylinder is not operating normally, you should contact your

Herrmidier Representative with an explanation of the problem.
However, in the continuing operation of this humidier, replace-

ments of this part are your responsibility as part of routine main­tenance.

Trion/Herrmidier shall not be responsible for loss of use of

any product, loss of time, inconvenience, or damage to other
equipment, or any other indirect or consequential damage with
respect to property whether as a result of breach of warranty,
neglect, or otherwise.

THE WARRANTIES AND LIABILITIES SET FORTH ARE IN
LIEU OF ALL OTHER WARRANTIES AND LIABILITIES, EX­PRESSED OR IMPLIED, IN LAW OR IN FACT, INCLUDING IM­PLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
FOR PARTICULAR PURPOSE.

The foregoing shall constitute the total liability of seller in the
case of defective performance of all or any of the equipment or
services provided to Buyer. Buyer agrees to accept and hereby
accepts the foregoing as the sole and exclusive remedy for any
breach or alleged breach of warranty by Seller.

Herrtronic® MD Series

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3

Installation, Operation, & Maintenance Manual

Water Level

Output

II. UNIT OPERATION

Herrtronic MD: Basic Operation

Controlled humidication requires a very precise control sys­tem. The Herrtronic MD utilizes a microprocessor to monitor
performance and maintain humidity. Further, the Herrtronic
MD evaluates the operation and alerts the operator to prob­lem conditions and prevents undesirable operation:

1. Start-up: On initial start-up (prompted by a call-for-hu-

midity), the ll valve opens allowing water to enter the

cylinder. When the water level rises to the electrodes,

current will ow and the water will begin heating. As

the water temperature increases, its conductivity also in­creases, accelerating the rate of temperature increase.

When the output reaches the “capacity set point,” the ll

valve closes. The output capacity may continue to rise
slightly beyond the “capacity set point.” As the water
boils away, the water level falls. This results in a reduc­tion in output capacity.

2. Normal Operation: Upon achieving “capacity set point,”
the system begins operation in a steady state mode.
Output capacity slowing decreases until the elapsed “cy-

cle time” opens the ll valve to replenish the water level

until the “capacity set point” output is achieved. As the
mineral concentration in the water increases, the water
conductivity also increases. Accordingly, the rate of boil­ing increases. Eventually, the rate of boiling reduces the
output capacity below the “low drain threshold” before

the “cycle time” initiates the ll cycle.

At this point, the drain valve opens discarding the min­eral laden (highly conductive) water, replacing it with
fresh water, that lowers the mineral concentration until
the system is restored to the steady state mode.
The steady state operating mode continues with small
increases in the water level to maintain output capacity
(by exposing new electrode surface).

3. End-of-Cylinder Life: Steady State operation continues
with “ll and boil” and periodic drain cycles with ever in­creasing water levels. Eventually, the water level reach­es the cylinder full electrode, representing the maximum
allowable water level inside the cylinder. The system
output begins to decrease since there is no new elec­trode surface to expose. If the system operates continu­ously without achieving “capacity set point,” an “end of
cylinder life” fault will be displayed.

High Drain

Threshold

Capacity
Set Point

Low Drain
Threshold

Cylinder

Full

HERRTRONIC MD: Basic Operation

1. 2.

Hours of Operation

Steadily Increase

Water Level

3.

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Herrtronic® MD Series

Installation, Operation, & Maintenance Manual

Relative Humidity %

Time

Types of Control

The Herrtronic MD System is available with (3) types of con­trol ---(1) On/Off, (2) Proportional, (3) Proportional + Integral:

1. On/Off – Humidity is sensed by a humidistat that pro-

vides an On/Off input to the humidier. Humidity varies

above and below the setpoint based on the tolerance
and accuracy of the humidistat.

2. Proportional – A proportional controller produces a sig­nal (ohms, volts DC, or milliamps DC) corresponding to
the difference between the control humidity and the hu-

midity setpoint. The humidier’s output increases as this

difference (and signal) increases. Humidity variations
will be smaller than with “On/Off” control and the control
humidity will be maintained within the bandwidth, toler­ance, and accuracy of the controller.

Types of Control

60

3. Proportional + Integral – Over a repeating time period
the “P+I” control simply evaluates the difference be­tween the average control humidity and the control hu­midity setpoint and adjusts the bandwidth to minimize
the “offset.” Optimal control is attained in most cases
with this alternative.

NOTE

If your application is unique or water is excessively

“clean” or “dirty,” consult Herrmidier for assis­tance in matching your humidier, water treatment,

and its control scheme to your application!

55

50

45

Offset Correction

On/Off Control
Proportional Control
Proportional + Integral Control
Set Point

40

0 5 10 15 20 25 30 35 40 45 50 55

Herrtronic® MD Series

P + I Bandwith

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Installation, Operation, & Maintenance Manual

III. INSTALLATION INSTRUCTIONS

Allowable Operating Conditions:

Ambient Temperature: 40ºF - 120ºF (4ºC - 50ºC)
Ambient Relative Humidity: 0% to 90%
Line Voltage: -15% to +10% of Nominal
Frequency: 50/60 Hz.
Supply Water Temperature: 40ºF-100ºF (4ºC-38ºC)
Supply Water Pressure: 20-100 psig
Supply Water Conductivity:

• 70-1000 mincromho (on-off control)

• 200-1000 micromho (prop or P + I control)

(See Figure 30 & 31 on page 27 for alternative water conditions)

Maximum Duct Static Pressure: 5” MDM, 7” MDS/MDD
units

NOTE: If units are mounted in outdoor enclosures, conditions
inside enclosure must be maintained as shown above.

Mounting

The cabinet is designed to safely contain the working com-

ponents of the Herrtronic MD humidier and dissipate heat to

protect the electronics. Herrtronic MD Series electronic steam
humidiers, room distribution units, steam pipes, and any ac­cessories should be located in a manner to facilitate routine in­spection and any necessary maintenance. The unit should not
be located above (such as false ceilings) or around valuable
property, where a malfunction could cause damage. Correct

positioning of the Herrtronic MD humidier is important to allow

for proper operation and easy maintenance. Minimum clearance
around the cabinet should be maintained as follows:

Unit Clearances By Model

Unit Series MDM

5-30 Lbs.

Left 2” 2” 2”

Right 20” 20” 20”

Top 12” 12” 12”

Bottom 10” 10” 10”

MDS

10-100 Lbs.

MDD

110-250 Lbs.

Four lag bolts, (2) 5/16” and (2) 1/4”, are supplied with the MDS
and MDM units which are designed to be secured to a wall. In­stall the top two lag bolts (5/16”) according to the dimensions in
Figure 1. Hang the unit on the wall, and then install the bottom
two lag bolts (1/4”) and secure all four bolts. Be sure the unit is
level and mounted directly to the wall to wood studs at least 2”
thick (or equivalent).
Operating weights are as follows:

• MDM - 82 lbs.

• MDS - 131 lbs.

• MDD - 258 lbs.

WARNING!
Do not mount any controls inside the unit or tap power from
any location in the unit, except as stated in these instruc­tions. Do not place objects near the cabinet. Do not attach
to dry wall without studs.

NOTE
To mount the Room Distribution Unit, refer to the “supple­mental” RDU Installation Instructions.

Plumbing

To make the necessary connections for water ll and drain,

the following steps are required: (refer to Figure 2 for drain
location)

1. Install an external shutoff valve between the water supply

and the humidier for ease in servicing the unit.

2. Connect water supply to 1/4” compression tting on the
bottom of the cabinet.

CAUTION!

Do not use reverse osmosis or demineralized water treatment

without rst consulting the factory. This water may not be suf­ciently conductive to allow proper operation. Consult factory

if water is outside the range of allowable conductivities. Do
not use hot water.

MDS MDM

10-100#

5.2516.004.25

4.00

22.38

1.81 21.89 1.81

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Figure 1

.75 Typ.

Both units

Ø .38" x Ø .75"
Keyhole Slot
Typ.

Ø .25 Typ.

5-30#

16.001.50 1.50

1.82

21.56

Herrtronic® MD Series

Installation, Operation, & Maintenance Manual

3. Connect the ¾” tube from the accessory pack to the drain
reservoir. Cut hose to necessary length.

WARNING!

Be sure that the ¾” drain tube is not kinked or bent in a man-

ner to prevent free owing drainage from the drain reservoir

to the drain pipe.

4. Insert the other end of the tube into a minimum 6” length of
1 ¼” minimum I.D. copper line. The balance of the drain
line should be 1” I.D. minimum with a minimum 1/8” per foot
slope. (See Figure 2)

Figure 2

WARNING!
If the drain line is exposed, it is recommended that it be in­sulated for safety. Do not use PVC drain line unless “Drain
Tempering” is enabled (see page 16-17).

NOTE
Inlet water pressure must be in the range of 20-100 psig.
Consult the factory if you are outside this range. Softened wa­ter may be used but requires that the low drain threshold be
adjusted (refer to Fig. 30 page 27). Drain water can be tem­pered to lower its temperature (refer to page 16).

3/4" MIN. I.D./1" MAX O.D.
FLEXIBLE DRAIN CONNECTION

RECOMMENDED

DRAIN RESEVOIR

4" RECOMMENDED

8"

6" MIN. LENGTH OF 1-1/4" MIN. I.D.
COPPER LINE. IF PVC IS USED, LOCAL

CODES REQUIRE A LOWER TEMPERATURE
DRAIN WATER, ADD DRAIN TEMPERING.

BALANCE OF DRAIN LINE TO BE 1" MIN. I.D.

WITH A MINIMUM PITCH OF 1/8" PER 12" OF RUN

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Installation, Operation, & Maintenance Manual

Supply Power (See Electrical Characteristics Table Below)

1. Ensure that adequate service is available to carry 125% of
rated amp level.

2. Field wiring of the main power supply is connected directly
to the contactor (single contactor units) or to a power distri­bution block (multiple contactor units) located in the electri­cal compartment. A ground lug is provided for the ground
wire.

3. Install external overcurrent protection and provide wiring in
accordance with the NEC, state and local code.

4. Power supply must be “clean”; free of spikes, surges and
sags; -15% to +10% of Nominal. Ground should be a true
earth ground.

Steam Distribution for Ducted Systems

Each steam cylinder requires at least one outlet for steam via
a duct distributor or Room Distribution Unit. (See RDU supple­ment for Room Distribution Unit)

Steam Distributor Pipes

Herrmidier supplies stainless steel duct distributor pipe(s) for

use in injecting pure steam into ducts. Refer to Figure 3, 4, or 5
for proper placement. A minimum of 3’ clearance downstream
is required for most applications. However, differing pyschro­metric conditions may require a greater or lesser steam absorp­tion distance. Consult the factory if you have any questions or
need to exchange your standard distribution system for a rapid
absorption CS-Series Distribution system.

NOTE

• The rubber steam hose carries steam to the distributor pipe
and condensate back to the unit. It must have an 8% (1”
per foot) pitch back to the unit. Support the steam hose so
it will maintain the proper pitch when in operation or at rest.

• If any low spots are in the steam line or the unit is mounted
higher than the distribution system, spitting may occur from
the steam distribution pipes. A condensate separator (EST-

250) is available from the factory. (See Fig. 6)

• If you must split the discharge of one steam outlet into two
ducts with the same static pressure, a “Y” connector (EST-

255) is available from the factory. The length of steam hose
after the “Y” connector must be the same for equal distribu­tion of steam. (See Fig. 8)

• Mount the unit as close to the distribution pipe as possible.
Use 1 ½” Type L insulated copper pipe whenever the length
of run exceeds 20 feet. Do not exceed a 30 foot run as the
capacity of the unit will be decreased by as much as 15%
and the increased static pressure could cause problems

with the ll system.

• Maximum duct static pressure: 5” MDM units, 7” MDS and

MDD units.

• Internal duct insulation should be removed in the “bulk
evaporation” zone (Consult factory representative).

• Steam holes in the distribution pipe are located 2” from
mounting plate and designed for a maximum duct wall
thickness of 1”. Consult factory if special hole locations
are required.

• Do not mount the standard distribution pipe in a vertical
downow or vertical position in a horizontal ow system.

Special pipes are available, consult the factory.

Steam Output

Lb/hr 5 10 15 20 25 30 40 50 60 70 80 90 100

Kg/hr 2.3 4.5 6.8 9.1 11.4 13.6 18.2 22.7 27.2 31.8 36.3 40.9 45.4

Voltage Electrode Current (amps)

208/1

240/1

277/1

208/3

240/3

380/3

440/3

460/3

480/3

575/3

600/3

KW = .333 X Lbs/Hr
Amps(1Ph) = KW X 1000 / (Voltage)
Amps(3Ph) = KW X 1000 / (Voltage X 1.732)
Min. Circuit Ampacity = 1.25 X Rated Electrode Current (Note: with RDU add .5 Amps @ 208/240 Volts or add .25 Amps @ 480 Volts)
Minimum Circuit Ampacity determines wire size (AWG)

8.0A 16.0A 24.0A 32.0A 40.0A 48.0A 64.0A

6.9A 13.9A 20.8A 27.8A 34.7A 41.6A 55.5A 69.4A

6.0A 12.0A 18.0A 24.0A 30.1A 36.1A 48.1A 60.1A

4.6A 9.2A 13.9A 18.5A 23.1A 27.7A 37.0A 46.2A 55.5A 64.7A 73.9A 83.2A 92.4A

4.0A 8.0A 12.0A 16.0A 20.0A 24.0A 32.0A 40.1A 48.1A 56.1A 64.1A 72.1A 80.1A

2.5A 5.1A 7.6A 10.1A 12.6A 15.2A 20.2A 25.3A 30.4A 35.4A 40.5A 45.5A 50.6A

2.2A 4.4A 6.6A 8.7A 10.9A 13.1A 17.5A 21.8A 26.2A 30.6A 35.0A 39.3A 43.7A

2.1A 4.2A 6.3A 8.4A 10.4A 12.5A 16.7A 20.9A 25.1A 29.3A 33.4A 37.6A 41.8A

2.0A 4.0A 6.0A 8.0A 10.0A 12.0A 16.0A 20.0A 24.0A 28.0A 32.0A 36.0A 40.1A

1.7A 3.3A 5.0A 6.7A 8.4A 10.0A 13.4A 16.7A 20.1A 23.4A 26.7A 30.1A 33.4A

1.6A 3.2A 4.8A 6.4A 8.0A 9.6A 12.8A 16.0A 19.2A 22.4A 25.6A 28.8A 32.0A

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Herrtronic® MD Series

Installation, Operation, & Maintenance Manual

Steam Distribution for Ducted Systems

DUCT HEIGHT

10" - 16"

(254MM) - (406MM)

(76mm)

3"

DUCT HEIGHT > 16"

(406mm)

DUCT HEIGHT

10" - 16"

(254MM) - (406MM)

AIR

6.5" (165mm)

FLOW

H

3.00" (76mm)

8.00

(203mm)

H

-5" (127mm)

h=

2

h

FIGURE 3 - SINGLE DISTRIBUTOR PIPE FIGURE 4 - DUAL DISTRIBUTION PIPES

DUCT HEIGHT>16"

(406MM)

6.5" (165mm)

h/3

AIR

FLOW

DUCT HEIGHT > 16"

(406mm)

h

3"

(76mm)

EST-250

SEPARATOR

(H-15)

2

h (in) = 6 +

CONDENSATE

H

h

h/3

h/3

3.0"

FIGURE 5 - MULTIPLE DISTRIBUTION PIPES

MIN. 8% (1" PER FOOT)

10" MIN.
(254mm)

NO SAGS

ALLOWED

CYL FULL

FAULTPOWER

ON/OFF

BACK

ENTER

FAULTS

HERRTRONIC MD

STEAM DISCHARGE MUST ALWAYS

BE FROM THE TOP OF DISTRIBUTOR

FIGURE 7 - STANDARD DUCT DISTRIBUTION

8.00

(typ.)

HORIZONTAL DUCT

VERTICAL DUCT

CYL FULL

FAULTPOWER

ON/OFF

BACK

ENTER

FAULTS

HERRTRONIC MD

½" TUBE

TO NEAREST

OPEN GRAVITY DRAIN

FIGURE 6 - INSTALLATIONS WITH UNAVOIDABLE LOW SPOT

EST-255

"Y" CONNECTOR

POWER FAULT

CYL FULL

BACK

ON/OFF

ENTER

FAULTS

HERRTRONIC MD

FIGURE 8 - TWO SEPARATE DUCTS

AT LOWEST

POINT

Herrtronic® MD Series

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9

Installation, Operation, & Maintenance Manual

Controls

The Herrtronic MD Series Humidier has the capability to utilize

one of three types of control schemes.

1. On/Off

2. Proportional

3. Proportional + Integral

Controls may be supplied by the factory or others. The following
information applies to all controls factory supplied or furnished
by others. All external electrical control circuits are to be con­nected to the unit using the twelve pole terminal strip located
in the electrical compartment. The terminal strip is accessed
through the side electrical compartment door. Field wiring from

humidistat to humidier and between safety devices, such as

high limit humidistat and air proving switches, should be 18
AWG stranded or 20 AWG solid wire. If conduit is not used with

the controls wiring, install the black plastic ngered bushing (in

accessory pack) and completely seal with RTV silicone.

Wall devices should be mounted at a height similar to that of a
typical thermostat and should be located in an area that will pro-

vide good representation of the overall space being humidied.

Do not mount wall devices directly in the air stream of a supply
grille or room distribution unit.

Duct control devices should be mounted in a location where the
humidity and temperature are uniform, usually the return duct.
Do not mount in front of the steam distributor or in a mixing,
turbulent, or isolated area.

Duct high limit devices should be mounted downstream of the
steam distributors-far enough that under normal conditions in
the air stream, the steam has been completely absorbed, typi­cally 10 ft. The device should be located such that it can sense

humidied air as it approaches saturation. Do not mount in dead

air spaces such as inside of corners or erroneous operation may
result.

Air proving devices should be mounted so that they sense air

ow (or the absence of it). Wire the device so that it closes when
air ow is present and will open when there is no air ow. The
purpose of the device is to prove that air ow is present before

steam is distributed into the duct.

The following information and diagrams are shown for each con­trol scheme. Please refer to the control scheme that your humid­ier was set up for and follow the diagram for control circuit con­nections. The factory-set control type and signal are indicated
on a label adjacent to the controls terminal strip.

Air Flow Switch High Limit Stat

1
2
3

Control Humidistat

4
5

68.1 k Resistor

6

Ω

7

See Note Pg. 28

Mode 2 - Proportional Operation

1. If two position airow and/or high-limit humidistat is used
wire as shown in Figure 9.

2. Control Input - Interpreted by the humidier as a demand of

output signal. Input device should be linear. Unit can accept
any VDC or mADC signal within a range of 0-20 VDC or
mADC (See Fig. 10). Unit may also accept a resistive signal
0-135 ohms (See Fig. 11).

3. Limit Input - Unit may accept any modulating input within
the same ranges as the control inputs listed above.
a. Proportional VDC or mADC (See Fig. 12)
b. Resistive (See Fig. 13)

Additionally, a P + I sensor may be used as a limit

input.
c. VDC (See Fig. 16)
d. mADC (See Fig. 17)

_

4

FIGURE 10

5

+

_

4
5

OUT

FIGURE 11

6

+

FIGURE 9

VDC or
mADC
Signal

W

R

B

Control Circuit Connections

Mode 1 - ON/OFF Operation

1. Control Input - Unit will operate with any two position device
(See Fig. 9). Demand for humidity will close the contact.

2. Limit Input - Unit will operate with any two position device
(See Fig. 9). The humidistat contact will open on humidity
rise.

10 www.herrmidifier-hvac.com

FIGURE 12

FIGURE 13

8
9

8
9
10

_

VDC or
mADC
Signal

+

_

W

OUT

+

R

B

Herrtronic® MD Series

Installation, Operation, & Maintenance Manual

Mode 3. (Proportional + Integral)

1. If two position airow and/or high-limit humidistat is used,

wire as shown in Figure 9, page 10.

2. Control Input - Unit will accept any sensor input that pro-

vides a VDC (See Fig. 14A, wall or Fig. 14B, duct) or n­mADC (See Fig. 15) signal within a range of 0-20 VDC or
mADC that is proportional to the humidity level in the air.
The sensor may be direct or indirect acting but must not
have an impedance greater than 500 ohms, and should be
linear. Example - A direct acting 2 - 10 VDC wall sensor will
send a 2 VDC signal if the R.H. level in the space is 10%; it
would send a 10 VDC signal if the R.H. level is 90%. The

humidier receives this input and compares it to the control

setpoint that has been programmed into the unit. The mi­croprocessor modulates the output capacity of steam. The
adjustable integration period will review performance over
the given time and will make tuning adjustments by shifting
the proportional bandwidth to correct for over or under hu-

midication offsets automatically.

3. Limit Input - Unit can accept any sensor input as specied

above.
a. VDC sensor input (See Fig.16).
b. mADC sensor input (See Fig. 17).

7
8
9

FIGURE 16




PWR

GND

RH (0 -10 vdc Output)



HED3VSX

Duct

Sensor

(EST-1600)





4
5
6
7

FIGURE 14A

4

5
6
7




GND

RH (0-10 vdc Output)

PWR

GND

RH (0-10 vdc Output)

PWR



HEW3VSX

Wall

Sensor

(EST-1601)

HED3VSX

Duct

Sensor

(EST-1600)








External Off Switch

Should a eld installed remote off switch be required, follow

the wiring diagram below (See Fig. 18). Be sure to remove the
jumper wire between poles 1 and 3 on “Controls Terminal Strip.”
The remote off switch is to be wired between poles 1 and 3. This
switch will override the unit on/off switch to turn the unit off only,
it will not restart the unit. The unit must be turn back on by the
unit on/off switch.















Herrtronic® MD Series



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11

Installation, Operation, & Maintenance Manual

Remote Alarm

The Herrtronic MD Humidier is equipped with a remote alarm

output. It is a triac output that may be used to energize an exter­nal relay or buzzer to indicate an alarm condition is present. The
alarm output is activated whenever an indicating fault condition
exists. When units are networked together, the master’s alarm
contacts will close if a fault occurs at either the master or one of
the slave units. The contacts are connected at poles 1 and 2 of
the remote alarm terminal strip 3.

In order to use the remote alarm output with a Building Manage­ment System, the remote alarm output must be used to energize
a mechanical relay. The contacts of the external relay may then
be wired to an input on the BMS to indicate if an alarm condition
is present. The remote alarm output may not be used like a dry
contact to a BMS.

Do not exceed the contact specications!

Contact rating:

• 24 VAC - 3.0 A

• 24 VDC - 2.1 A

Unit Networking

When networking units together in a master/slave congura­tion, be sure to maintain polarity between poles 11 and 12 on
all units. Units are to be wired as a parallel circuit. More than
one branch is allowable so that the master unit can be centrally
located (See Fig. 19). A maximum of 29 slave PC boards (29

MDS or MDM units or 14 MDD units) may be congured as a

network. Included in each installation pack is a 120 ohm resistor.
This resistor should be inserted into R28 on the microprocessor
board (see Fig. 32) on the appropriate end units of the chain.
(Refer to Fig. 19)
























 


























 





































12 www.herrmidifier-hvac.com

Herrtronic® MD Series

Installation, Operation, & Maintenance Manual

IV. OPERATING INSTRUCTIONS

Your unit has been pre-set for 1 of 3 control modes:

1. On/Off

2. Proportional

3. Proportional and Integral

With each control mode, there is a specic set of operating parameters and setpoints that apply. All of the setpoints have been preset
at the factory to simplify the start-up procedure. The following table identies the parameters, setpoints and preset values that apply

to each mode. Below the table is a more detailed description of the setpoint parameters. All setpoints have pre-set default values to
simplify programming. Instructions for adjustment follow.

Setpoint Parameters

Control Mode

1 2 3

Menu to

Adjust

Adjust Setpoint Range

MDM

Preset Values

MDS/MDD

Preset Values

Control Setpoint X 2 20-98% 35% 35%

Limit Setpoint (Note 3) X X 2 20-99% 75% 75%

High Humidity Alarm X 2 20-100% 99% 99%

Low Humidity Alarm X 2 10-98% 10% 10%

Capacity Setpoint X X X 2 10-100% 100% 100%

Auto Drain X X X 2 0-99 Days 7 Days 7 Days

Low Drain Threshold X X X 2 50-100% 85% 80%

Steam Output Rating X X X 3 0-999 lbs/hr. 5-30 lbs/hr. 10-100 lbs/hr.

Electrode Current Rating X X X 3 0-999 Amps As required As required

High Drain Threshold X X X 3 100-120% 110% 110%

Cycle Time X X X 3 30-300 Sec. 75 /(90) See note 1 130 /(150) See note 2

Proportioning Band X 3 +/- 2 to 15% +/- 10% +/- 10%

Integration Period X 3 0-60 Min. 30 Min. 30 Min.

Throttling Range (Note 3) X X 3 0-25% 10% 10%

Unit Address X X X 3 0-99 01 01 MDS (00, 01 MDD)

Low Drain Limit X X X 3 25-75% 50% 50%

Manual Drain X X X 5 Active/Inactive Active Active

Leakage Protection X X X 5 On/Off Off Off

End of Cyl. Life Setpoint X X X 5 1-500 hrs. 6 hrs. 6hrs.

Electrode Run Time X X X 5 0-999,999 hrs. 0 0

Limit Input (Note 3) X X 5 Enable / Disable Enable Enable

Control Input X X X 5 Enable / Disable Enable Enable

Drain Tempering X X X 5 Active/Inactive Inactive Inactive

Notes:

1. On units where voltage is 380 VAC or greater, the cycle time is 75 seconds. On units where voltage is 240 VAC or less, the cycle time is 90 seconds.

2. On units where voltage is 380 VAC or greater, the cycle time is 130 seconds. On units where voltage is 240 VAC or less, the cycle time is 150 seconds.

3. If a unit is ordered with the modulating high limit, the Limit Input will be ENABLED. If an “On/Off” type or no high limit is used, the Limit Input and Throttling Range
screens will have been eliminated.

Parameter Denitions: All Control Modes

• Output Rating - Unit design capacity (lbs/hr).

• Electrode Rating - Current rating that corresponds to unit design capacity.

• Capacity Rating - Output capacity as a % of the output rating.

• Low Drain Threshold - Minimum output capacity % that initiates a drain cycle.

• High Drain Threshold - Maximum output capacity % that initiates a drain cycle.

• Auto Drain - Time in days between system shutdown and cylinder drain.

• Manual Drain - Operator activated cylinder drain

• Drain Tempering - Allows mixing of cool inlet water with drain water for tempering

• Cycle Time - Time in seconds between ll cycles.

• Unit Address -In network installation; “master unit” is “00”, slaves “01” to “99”.

• Leakage Protection - Electrically disconnect electrodes during drain cycle.

• Electrode Run Time - Hours of cylinder operation.

• Control Input - Space condition humidity input device.

• End of CYL Life Setpoint - Unit has not achieved desired output within specied

time.

Specic Control Modes (See Chart)

• Control Setpoint - Desired % RH

• Limit Input - Modulating high limit from a controller or sensor

• Limit Setpoint - Maximum allowable % RH limit

• Low Humidity Alarm - Indication of control humidity level below alarm setpoint.

• High Humidity Alarm - Indication of control humidity level exceeding alarm set-

point.

• Proportioning Band - Humidity span around control setpoint where modulation
occurs.

• Integration Period - Length of time period for %RH evaluation and adjustment.

• Throttling Range - Humidity range below limit setpoint where modulation occurs.

All setpoints have pre-set default values to simplify programming -Instructions for
adjustment follow.

Herrtronic® MD Series

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13

Installation, Operation, & Maintenance Manual

SETPOINT 35%

Programming

When power is initially applied (i.e. close the disconnect), the
liquid crystal display (LCD) will become active (without user ac­tion). A “signature” screen will appear:

HERRMIDIFIER INC.
HERR 002 VER 5.X

“Ver 5.X” denotes the program level of the microprocessor. The

specic “Ver 5.X” level should be included in any inquiry to a
Herrmidier representative or the factory. After a brief pause, the

‘”Main Menu” will appear:

SYSTEM OFF 000% X 01
MENU Y

The contents of the display provide the following
information:
“System Off” - The “ON/OFF” button is in the “OFF” position.
“000%” - Output capacity in % “0%” = 0 lbs /hr. Range is 0-100%

“X” - Control Mode:

1. On/Off

2. Proportional

3. Proportional + Integral

“01” - Unit Address
“Menu Y”- Designates program MENU:

Menu 1 - Status Items (non-adjustable)
Menu 2 - Setpoint Adjust (non-secured)
Menu 3 - Setpoint Adjust (secured by “password”)
Menu 4 - Network Communication
Menu 5 - Maintenance Adjust (infrequently used options)

Prior to start-up, the operator should review and/or adjust all

setpoints and, if needed, establish the network conguration.

Programming is accomplished as follows:

1. Press the “up” arrow for Menu 2. The LCD screen will read:

2. Press “Enter” to initiate the Menu program. The LCD will
read:

CONTROL 3 01

3. Press the “up” or “down” arrow button to increase or de­crease the pre-programmed setting as desired.

4. Press “Enter” to register the setpoint and move to the next
setpoint.

5. Repeat steps “3” and “4” until all of that Menu’s setpoints
are registered.

6. Press “Back” to return to the MAIN MENU. (Menu 1)

7. Press the “up” arrow for Menu 3. The LCD will read:

SYSTEM OFF 000% 3 01
MENU 3

8. Press “Enter”. The LCD will read:

ENTER PASSWORD

NOTE!
Menu 3 is password secured. The setpoints in this menu are
protected from routine adjustment. The unit is shipped new
with three presses of the “Enter” key as the password.

9. To set a new password, six keystrokes are required. The

rst three keystrokes tell the unit that a new password is

being set. The last three keystrokes are the actual pass­word. To set a new password, press “On/Off”, “up” arrow,
“Enter” and any (3) additional keystrokes - i.e. “up” arrow,
“down” arrow, “Back”. These last (3) keystrokes become
your “password.” Any subsequent revisions to Menu 3 set­points will require use of this three keystroke “password.”

SYSTEM OFF 000% 3 01
MENU 2

NOTE!
Control Mode may be: (1), (2), or (3). This example pertains
to mode (3). In control modes (1) and (2), not all setpoints will

appear (The table on page 13 identies parameters visible in

each mode).

14 www.herrmidifier-hvac.com

NOTE!

If the wrong password is entered, the LCD will read:

INCORRECT
PASSWORD

Refer to step 9. The last (3) keystrokes become the new pass­word.

Herrtronic® MD Series

Installation, Operation, & Maintenance Manual

10. After establishing the “password”, repeat steps 3 through 5
to program Menu 3. Press “Back” to return to MAIN MENU.
(Menu 1)

11. Press “up” arrow for Menu 5. The LCD will read:

16. Press “up arrow” if you would like to access slave 2 and “up
arrow” again for slave 3, etc.

17. From the screen described in step 15, press “Enter” to ac­cess Slave 01. The LCD will read:

SYSTEM OFF 000% 3 01
MENU 5

12. Repeat steps 3 and 4 to complete Menu 5. The press “Back”
to return to the MAIN MENU (Menu 1)

NOTE!
Programming of the setpoints for the unit is now complete. If
there are multiple Herrtronic MD’s networked together OR you
are programming a MDD (110-250 lbs/hr.) unit, continue to
step 13. Otherwise proceed to STARTUP with CHECK LIST,
page 16.

Access Menu 4 for MDD Models only (2 tanks) or Networked
Units. This allows you to program the slave circuit board.

NOTE!
The address in the below screen is now 00. This allows the
‘Master” unit access to any “Slave” in the “Network.” Only one
Master unit “00” per Network can be used.

13. Press the “up” arrow for Menu 4. The LCD screen will read:

SYSTEM OFF 000% 3 00
MENU 4

SYSTEM OFF 000% 2 01
MENU 1

NOTE!

On MDD units, the address of the slave unit is factory set as

01. To reprogram the Slave, repeat steps 1 through 12 de­scribed on previous page.

NOTE!

If communications are not successful, the LCD will read:

NO REPLY ENTER TRY
AGAIN BACK TO EXIT

Possible sources for failed communication attempt:

A. Chosen Slave does not exist.
B. Slave unit does not have power connected.
C. Faulty communications wiring

1. Improper polarity of RS-485 (Controls Terminal
Strip Poles 11 & 12).

2. Resistor required to signify the beginning and end
of the “Network” is not installed correctly. On indi­vidual MDD units, these resistors are not neces­sary. See “Installation/Networking” section for clari-

cation.

D. It is possible for high levels of Electro-Magnetic Interfer-

ence (EMI) to impede communications between units.
Press “Enter” to try communications again, or “Back” to
return to “Master” units’ Main Menu.

14. Press “Enter”. The LCD will read:

POLLING SLAVE PRESS
BACK FOR MASTER MENU

This screen will appear only when power has been initially ap­plied or reapplied. Wait about (5) minutes to allow the micropro­cessor to “Poll” the network.

15. After returning to the screen described in step 13, press
“Enter”. The LCD will read:

ENTER SLAVE
NUMBER 01

Herrtronic® MD Series

18. To return to “Master” unit (unit address 00) press the “up”
arrow (3) times. The LCD will read:

SYSTEM OFF 000% 2 01
MENU 4

19. Press “Enter”. The LCD will read:

LEAVING SLAVE PRESS
BACK FOR MASTER MENU

20. Press “Back” and return to “Master” unit (unit address 00)
Main Menu.

21. To program additional slaves, repeat steps 13-20. Program­ming is complete. Proceed with START- UP section.

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15

Installation, Operation, & Maintenance Manual

Start-up with Check List

After all programming is completed (and the total installation is
complete), the Herrtronic MD system is ready to start. At the
end of START-UP section is a CHECK-LIST. The CHECK-LIST
is intended to highlight critical installation points. A poor installa-

tion frequently results in start-up difculties, and always results
in less than ideal operation of the humidier.

IMPORTANT- Before any Herrmidier representative or the

factory is contacted with a start-up problem; please have the
checklist completed as far as possible.

1. Set all controls to their lowest setting (control and high limit
if applicable). In systems using distributor pipes, make sure
the fan is operating. By placing the controls at their lowest
setting and turning the unit “ON” at the “ON/OFF” button,
the unit should not try to initiate production of steam. On
MDD units it is necessary to turn the Slave “on” through the
communications, Menu 4.
Find the lowest setting in each Control Mode as follows:

• Mode 1 (On-Off)-Turn the dial to the OFF position or
its lowest setting.

• Mode 2 (Proportional) - Set the controller to send the
lowest signal in the range (i.e. 4 mA in a direct 4-20
mA range).

• Mode 3 (P + I) - Set “Control Setpoint” through Menu
2 at least 11% below the “Control RH” displayed in
Menu 1.

2. Set high limit to its highest setting (all control modes).

3. Set CONTROL input to get the Herrtronic MD to attempt
100% of capacity as follows:

• Mode 1 (On-Off) - An audible “click” will be heard
when the humidistat is asking for full output.

• Mode 2 (Proportional) - Set controller to send
Herrtronic MD a full signal (i.e. 20 mA in a direct 4-20
mA output range).

• Mode 3 (P + I) – Set “Control Setpoint” through Menu
2 20% Above “Control RH” displayed in Menu 1.

4. TURN UNIT ”ON”. (ON MDD UNITS, BOTH MASTER AND
SLAVE BOARDS MUST BE TURNED “ON”.) Slave units
can be turned on via the Master board through communica­tions or directly from the slave circuit board. Once the unit
gets the signal to run and unit is turned “On”, the contactor

will pull in within 5 seconds, followed by the ll valve be­ing energized. The unit will attempt to ll to FULL OUTPUT

(100%) or CYLINDER FULL. If the unit fails to reach 75%

of capacity on the initial ll (as shown by CYLINDER FULL

light illuminated and <75% Output), you should use the
jumper wires enclosed in the accessory envelope and ar­range them as shown on the diagrams on Figure 28, page

21. Be sure to disconnect power rst and re-tighten each of

the electrode knobs.

NOTE!
THIS WILL NOT BE POSSIBLE ON UNITS WHICH AL­READY HAVE POWER TO EACH ELECTRODE OR ANY
MDM. Before restarting the unit, drain half the water from the
cylinder using “Manual Drain” found in Menu 5.

5. If low conductivity water is being supplied, as indicated by
a low percentage of output (70% and under) and the CYL-

INDER FULL light is illuminated, you may want to articially

increase the output. This is accomplished by the following
procedure:

• Drain 1/2 the water from the tank using the manual
drain option in Menu 5.

• Add 1 Alka-Seltzer tablet

• Restart

• Repeat if needed

6. Fill System (Fig. 20) Check Points

• No leaks in system

• Virtually all the water entering the FILL TEE should

be going down the FILL TUBE as opposed to the
OVERFLOW TUBE. A slight adjustment may be
needed to the Metering Screw (Fig. 21) if water sup­ply pressure is too high. Turn the screw clockwise to
close, or counter clockwise to open.

























Figure 20

7. If you need to “TEMPER” the drain water because of lo­cal codes or low temperature drain piping is used, activate
“DRAIN TEMPERING” (Menu 5)

NOTE!
The drain water is TEMPERED or COOLED by the addition of
fresh water while the drain solenoid is open. The proper rate
of fresh water will cool the drain water and still allow the hu-

midier to drain freely. Use the ll valve adjusting screw (Fig.

21) to regulate the owrate of the cool inlet water. The amount

of tempering will depend on incoming temperature and pres­sure of the water supply.

8. Once the water is boiling and steam is being produced,
check the following:

• No leaks in the steam distribution lines or connec­tions.

• The steam has a clear path from the cylinder to its
distribution points. Any low spots in the steam distri­bution line must be trapped. (See Fig. 6)

9. Unit needs to drain hot water to check proper drain line in­stallation. Unit may be draining through normal operation,
but if not, initiate a drain through the MANUAL DRAIN in

16 www.herrmidifier-hvac.com

Herrtronic® MD Series

Installation, Operation, & Maintenance Manual

Menu 5. Once hot water is being drained, check the follow­ing:

• Steam condensing on the bottom of the cabinet.
Correct by lowering the drain line or adding DRAIN
TEMPERING.

• Flash steam entering the steam cylinder compart­ment due to inadequate drain line.

• Flash steam entering the electrical compartment if
the knockout for the control wires isn’t sealed. This
should be sealed even if there doesn’t appear to be
any steam entering into the compartment. If conduit
is not used with the controls wiring, install black plas-

tic ngered bushing and completely seal with RTV

Silicone.

• Water must drain from unit freely. If there are restric­tions in the drain line, it will send hot water/steam up
into the CABINET DRAIN and/or the OVERFLOW
TUBE which will pool inside the cabinet and could

leak out of the unit onto the oor.

START-UP IS COMPLETED. MAKE SURE CONTROLLING
DEVICES ARE SET FOR DESIGNED CONDITIONS. PRO­CEED TO AND COMPLETE CHECK-LIST. AFTER INITIAL
WARM UP, SHUT UNIT DOWN, TURN OFF MAIN POWER
AND RECHECK TIGHTNESS OF POWER CONNECTIONS
WHILE UNIT IS WARM (TORQUE TO 15-20 in-lbs.).




















Figure 21

Herrtronic® MD Series

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17

Installation, Operation, & Maintenance Manual

1. MATCHES DATA PLATE

2. IS PROPERLY GROUNDED

3. CAN CARRY AT LEAST 125%

OF RATE AMP DRAW

4. DISCONNECT SUPPLIED BY

OTHERS.

MAKE SURE ALL HIGH VOLTAGE

ARE TIGHT.

ELECTRICAL CONNECTIONS

POWER SUPPLY:

PRE-STARTUP CHECKLIST

NO UNTRAPPED LOW SPOTS

IN STEAM SUPPLY.

ELECTRICAL CONNECTIONS ON

MAKE SURE ALL HIGH VOLTAGE

(15-20 in/lbs)

STEAM CYLINDER(S) ARE TIGHT

SEALED TO PREVENT FLASH STEAM FROM

KNOCKOUT FOR CONTROL WIRING MUST BE

ENTERING ELECTRICAL COMPARTMENT.

4"

RECOMMENDED

8"

RECOMMENDED

WITH A MINIMUM PITCH OF 1/8" PER 12" OF RUN

3/4" MIN. I.D./1" MAX O.D.

FLEXIBLE DRAIN CONNECTION

BALANCE OF DRAIN LINE TO BE 1" MIN. I.D.

AIR FLOW IS HORIZONTAL OR VERTICAL UPFLOW

A SPECIAL PIPE IS REQUIRED FOR VERTICAL DOWNFLOW,

AIR FLOW.

OR A VERTICAL DISTRIBUTOR PIPE IN A HORIZONTAL

18 www.herrmidifier-hvac.com

DURING FILL CYCLE CHECK TO SEE IF ANY

WATER IS DRAINING FROM UNIT. A LOT OF

WATER FLOWING OUT OF THE UNIT WOULD

INDICATE EXCESSIVE WATER PRESSURE.

AMOUNT OF WATER IS NOT UNCOMMON.

OR SUPPLY VALVE TO HUMIDIFIER. A SMALL

REDUCE THROUGH METERING FILL SOLENOID

TEMPERATURE DRAIN WATER. THIS IS NOT UNCOMMON

AND DRAIN TEMPERING SHOULD BE ENABLED.

6" MIN. LENGTH OF 1-1/4" MIN. I.D. COPPER LINE.

IF PVC IS USED, LOCAL CODES MAY REQUIRE A LOWER

Herrtronic® MD Series

Installation, Operation, & Maintenance Manual

Diagnostics

The Herrtronic MD humidier includes built-in diagnostics ca­pability to identify potential problems, protect the system, and
minimize service/repair time. Should the system detect a critical
condition, a “fault” warning will be displayed on the LCD. Cer­tain faults prompt immediate system shutdown to protect the
MD unit or ductwork. Other faults allow the unit to continue to
operate but alert the operator to potential problems that require
maintenance. Other faults, which are designed for initial system
tune-up or preventative maintenance, are classied as “non-in­dicating.” These faults are viewed by pressing the “fault” key on

the control panel. The table reects all of the faults the system

is capable of detecting. Please note, however, that certain faults
are unique to certain control modes or networked systems and
are only visible where applicable.

During operation, when an “indicating” fault occurs, the word
FAULT will be visible in the lower right hand section of the LCD.
The red fault light will also be illuminated.
If an “indicating” fault has been detected or a preventative check
is being performed, follow this procedure to determine the cause
of the fault:

1. The LCD must be in the MAIN MENU to access diagnos­tics. Press “FAULT” key to determine the type of fault.

2. Press the up arrow to determine if there is more than one
fault.

3. If possible, correct the condition causing the fault signal or
plan corrective action.

4. Press “ENTER” to clear the fault signal from the display.
When “ENTER” is pressed, all faults registered in the unit
will be cleared. If the condition causing the fault is not cor­rected, another fault signal will occur.

5. Under normal operating conditions, pressing the “FAULT”
button will prompt the following display:

NO FAULTS PRESENT
IN SYSTEM

In a multi-unit network, the master (“00”) unit will indicate a fault

within the entire network. To nd the fault(s), follow steps 1 and

2 for the master unit. If the display indicates “No Faults Present
In System,” then neither the Master, nor any Slave unit, has any
faults.

If any slave has a fault, the LCD will read:

System Fault Conditions

(See Troubleshooting Section for corrective action)

Fault Operation Status Comments

Current Overload (4) Shutdown and Drain

Contactor Failed (4) Continued Operation Humidication Re-

Cylinder Full Zero
Current

Fill System Fault (4) Shutdown and Drain

Zero Electrode Cur­rent

Non-zero Slowly De­creasing Amps

Non-zero Non-De­creasing Amps

Non-zero Non- In­creasing Amps

Non-zero Slowly In­creasing Amps

Cylinder Full Continued Operation Caused by low water

End of Cylinder Life
(4)

Air Flow / High Limit System Shutdown,

Hi Humidity Alarm (3)
(4)

Lo Humidity Alarm
(3)(4)

Humidity Sensor
Failed (3)

Slave “XX” Has Fault
(4)

Communication Port
Fault

Manual Reset(1)

Continued Operation Humidication re-

Manual Reset (1)

Continued Operation Humidication re-

Continued Operation Defective drain sys-

Continued Operation Defective drain sys-

Continued Operation Defective ll system

Continued Operation Defective ll system

Continued Operation Cannot achieve ca-

Automatic Reset (2)

Continued Operation Alarm threshold

Continued Operation Alarm threshold

Continued Operation
unless both fail

Continued Operation
of Master

Continued Operation
of Master

138% of Capacity
Setpoint Exceeded

quired

quired; unit not func­tioning properly

Fill for 15 min. – can­not achieve capacity
setpoint or cyl. Full

quired, no current
draw

tem

tem

conductivity, foam­ing, or end of cyl.
Life.

pacity and on cylinder
full or programmed
duration

Insufcient airow /

high limit setting ex­ceeded

achieved

achieved

Humidity less than
4% or greater than
100%

Slave has fault

Slave operation un­known

SLAVE XX HAS FAULTS

Utilize the communications (Menu 4) from the Master to access
the particular slave with fault(s) to determine the fault. (Refer to
communication instructions in the programming section). Press
the “up” arrow button to determine if there is more than one
“slave” that has a “fault.”

Herrtronic® MD Series

1. Manual reset requires the problem be corrected and the unit turned “on” at
the keypad

2. Automatic reset will resume normal operation once the circuit is closed.

3. Proportional + Integral Control Only

4. Indicating Fault

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19

Installation, Operation, & Maintenance Manual

Maintenance

To maintain efciency of the unit, the water level in the cylinder

will slowly rise as the electrodes become coated with minerals.
Progressively, the water level reaches the cylinder full electrode,
representing the maximum allowable water level. Eventually, all
of the usable electrode surfaces will be coated. After the end
of cylinder life setpoint has been reached, the LCD will read
“End of Cylinder Life” fault. Cylinder replacement should occur
to maintain satisfactory humidity levels. “End of Cylinder Life”
varies with water conductivity. Refer to the chart that follows:

Conductivity (micro-mhos)

(approximately)

70 2000

100 2000

135 1900

170 1800

250 1300

500 800

750 650

1000 500

Average Cylinder Life

(Hours)

on, allow cylinder to ll and check for leaks. AFTER INI­TIAL WARM UP, SHUT UNIT DOWN, TURN OFF MAIN
POWER AND RECHECK TIGHTNESS OF POWER CON­NECTIONS WHILE UNIT IS WARM (TORQUE TO 15-20
in-lbs.).

Extended Shutdown:

The humidier is set by the factory to drain if the unit doesn’t

operate for seven days. However, the drain time can be revised
through reprogramming (Refer to Page 14). Always drain the
cylinder completely if it will be off of an extended period of time
(see Auto drain feature, menu 2, page 13).

NOTE
Many factors in addition to water conductivity effect cylinder
life. Total dissolved solids (TDS) and exact mineral content
of the water can have negative effects on cylinder life. Your
representative will be happy to review your water analysis.
If you don’t have an analysis and are on a municipal system,
the municipal water authority will provide one free of charge.
Conductivity between 70 and 200 micromho is best handled
with “on/off” control. Discuss your application with the factory
if your water is in this range and “Proportional” or “Propor­tional + Integral” control is required. Water with less than 70

micromho may not be sufcient to allow the unit to operate.
Herrmidier has considerable experience optimizing the per­formance of your humidier on “fringe” water conditions. Con-

sult your representative.

To Remove the Cylinder:

1. Turn the unit “off” by pressing the “on/off” button. Drain the
cylinder completely using the manual drain (Menu 5).

2. Disconnect the power to the unit..

3. Disconnect the electrode power wires (and jumpers if used)

- noting the orientation, and the cylinder full electrode wire
from the cylinder. Remove the expired cylinder from the
cabinet.

4. Position the new cylinder in the cabinet. Place the new “O”
ring as shown in Fig. 22. Lubricate the “O” ring with water
only and install cylinder into drain cup, EST-1062, pushing

down rmly with a twisting motion.

5. Reconnect the power wiring (and jumpers if required) refer­ring to appropriate Figure on the next page that matches

the power wiring conguration of the unit. Be certain to use

lock washers on each electrode and tighten the electrode
knob (Fig. 25 or 29).

6. Installation is now complete, Reconnect power, turn unit

20 www.herrmidifier-hvac.com

Herrtronic® MD Series

Installation, Operation, & Maintenance Manual

FIGURE 23FIGURE 22

EST-1060-3
O-RING

POWER WIRE B

POWER WIRE A

CYLINDER

FULL

ELECTRODE

FIGURE 24

POWER WIRE A

POWER WIRE C

FIGURE 26

POWER WIRE H

POWER WIRE B

FIGURE 28

POWER WIRE G

POWER WIRE B

CYLINDER

FULL

ELECTRODE

POWER WIRE A

CYLINDER

FULL

ELECTRODE

JUMPER WIRE

FIGURE 25

FIGURE 27

POWER WIRE

C OR F

POWER WIRE

H OR K

POWER WIRE

B OR D

POWER WIRE G OR J

FIGURE 29

ELECTRODE CAP

LOCKWASHER

POWER WIRE

LOCKWASHER

POWER WIRE I OR L

POWER WIRE

A OR D

CYLINDER

FULL

ELECTRODE

ELECTRODE CAP

POWER WIRE

C OR F

JUMPER WIRE

POWER WIRE

B OR E

JUMPER WIRE

FIGURE 30

Herrtronic® MD Series

POWER WIRE

CYLINDER

FULL

ELECTRODE

ELECTRODE CAP

LOCKWASHER

POWER WIRE

JUMPER WIRE

LOCKWASHER

A OR D

LOCKWASHER

POWER WIRE

LOCKWASHER

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21

Installation, Operation, & Maintenance Manual

V. TROUBLESHOOTING GUIDE

General Maintenance Notes

WARNING!
High Voltage components are present in both the cylinder and
electrical compartments. Maintenance must be performed by

qualied individuals. Absolutely no other components may be
mounted inside or electrically tapped into humidier without

voiding the warranty.

A. Externally, controls of many congurations may be used

with your new MD series humidier. Herrmidier strongly

recommends the use of some type of control humidistat,
a high limit humidistat, and an air proving switch to insure

proper operation of your humidication system.

B. Electrode boilers operate by passing current through the

water utilizing the conductivity of the water itself as a cur-

rent path. The ow of current through the water generates

heat which boils the water and produces the steam required

for humidication. The diagnostic features of the MD series
humidier are designed to help you maintain and optimize

your system for years of service. If the fault light is illumi­nated, see the diagnostic section on page 19.

C. The wiring diagram, illustrated on page 34 (for MDD units,

the wiring diagram is located on pages 11 and 12 of the
“MDD Supplement”), clearly shows the path of the 24 VAC
control circuit. Control voltage leaves the transformer,
passes through a fuse and then into the circuit board. The
microprocessor has inputs and outputs for the humidistats
or sensors, contactor auxiliary pole, differential pressure
switch and the control loop. Power for the control loop goes
through the external off switch (optional), the door interlock
switch, and then back to the microprocessor. Understand­ing the wiring diagram will give you a better idea of the logic
of the MD series humidier and simplify your troubleshoot­ing.

D. If any changes to the physical board set-up are made, i.e.

capacity changes or resistor, the unit must be reset. You
may reset the unit by depressing the “reset” button on the
back of the board or turning the unit off and on through the
disconnect (See PC Board diagram on page 28).

E. If the circuit board needs to be changed, make sure the

ribbon cable connector from the main board to the display
board is as originally supplied (red stripe on top at LCD and
on the right at PCB). Reattach the (three) 11 Pin connectors
in the same manner. (J1, J3 and J5)

Operating The Humidier Without External Controls

The humidier has the capability to operate without any external
signals being sent to the unit. Being able to isolate the humidier

from the external controls is invaluable in troubleshooting. The
unit can be “jumped-out” whether it’s mode 1, 2, 3.

capacity setpoint) or cylinder full.

6. After conrming proper operation, reattach controls for
normal operation and remove added jumpers.

B. Mode 2 - Proportional

This signal is typically supplied by others. The MD has 2 sepa­rate VDC power supplies accessible from the controls terminal
strip (as shown on page 26). Either one of these outputs will be

sufcient to bring the MD into an operational state. You will need

to know the control signal being supplied and select the 5 VDC

or 2O VDC output from the control terminal strip. The humidier

will react in proportion to its programmed signal range.

Example: The humidier is set up for 0-10 VDC signal from the
BMS. The humidier is being jumped-out with the 5 VDC signal

from pole 6 to pole 5 on the control terminal strip. You can ex-

pect the humidier to ll to 50% output or cylinder full.

1. Remove any eld installed control wires; mark for re-
attachment.

2. Through Menu 5, disable limit input (if applicable).

3. Jump terminals 1 & 2 on controls terminal strip.

4. Jump terminals 1 & 3 on controls terminal strip.

5. Select 5 VDC from control terminal strip pole 6 or 20
VDC from control terminal strip pole 7 to jump to pole 5
on the controls terminal strip.

6. If signal provided is other than VDC, use the following
comparisons: mADC; 20mA = 20 VDC, resistance; 135
ohms = 2 VDC

C. Mode 3 - Proportional + Integral

If a problem is detected in the sensors, the diagnostics will pick
up the problem and display a fault with the sensor. To jump-out,
follow the steps 1-4 listed for Mode 2 above, then follow steps 1
through 3 below.

1. If the control signal is a DC voltage type with a maximum
signal level of 5 VDC or greater, or a DC millilamp type with
a maximum signal level of 20 mA or greater, apply a jumper
wire between poles 5 & 6 on the controls terminal strip.

2. A control RH level will be indicated based on the jumped

input signal and the factory board set up for the actual eld

control signal. i.e., board factory set for a 0-10 VDC control
signal, jumper wire applied between poles 5 & 6, the indi­cated control RH level (via Menu #1) will be approximately
50%.

3. Adjust the control setpoint relative to the control RH level
via Menu #2, keeping in mind the bandwidth, i.e., control
RH level is 50%, Bandwidth is +/- 10%, adjust the control
setpoint to 60%, or greater, to obtain 100% output from the
unit.

A. Mode 1 - On/Off

1. Remove any control wiring supplied by others; mark
wires for re-attachment.

2. Jump terminals 1 & 2 on controls terminal strip.

3. Jump terminals 1 & 3 on controls terminal strip

4. Jump terminals 4 & 5 on controls terminal strip.

5. After unit is turned ON, it should ll to 100% output (or

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Herrtronic® MD Series

Installation, Operation, & Maintenance Manual

Unit Detected Faults (Red Light is Illuminated)

Problem / Symptom Probable Cause Reason - Correction

Restricted Drain System Clean and replace as necessary

Overcurrent

When this condition occurs, the system
has sensed an excessive current draw
(138% of rated current) and has shut itself
down and drained completely to prevent
possible damage. The system has already
taken preventative action by attempting to
drain down prior to the fault condition oc­curring. Therefore, further analysis is re­quired before restart is attempted.

Fill System Fault

The unit has been in ll cycle for 15 min­utes continuously without reaching re­quired output or cylinder full. System will
shutdown and drain completely.

End of Cylinder Life

The cylinder is full and humidier has not

been able to achieve desired output within
setpoint.

High Humidity

Humidity in the space being measured by
the control sensor has exceeded the pre­set alarm level. This alarm is only avail-

able on units congured with P + I control

(mode 3).

Use of softened water without adjusting
operating parameters

Water conductivity in excess of 750
micromho

Expired steam cylinder – a mineral bridge
has developed allowing a short between
two electrodes.

If drain tempering is enabled and the rate

of ll is exceeding the rate of draining,
the tank will ll whenever the unit tries to

drain.

Restricted or blocked ll system (strainer,

solenoid, external shut-off valve.)

Partially or completely open drain valve.

Extremely low conductivity supply water

Cylinder expired-electrodes have been
consumed.

Extremely low conductivity supply water Add a 1/4 teaspoon of salt to the cylinder.

Tampering with the control humidity set­point.

Alarm set-point too close to control set­point

Humidier is powered but not operating

and RH is above setpoint

Sensor or wiring has failed.

See Fig. 30

See Fig. 30 and 31

Replace steam cylinder

Adjust the ll valve metering screw to
slow the rate of ll so the unit can drain

properly. See Fig. 21 for adjusting screw
location.

Replace

1. Reset your alarm setpoint.

2. Turn off humidier at main disconnect

until humidication season.

Low Humidity

Humidity in the space being measured
by the control sensor has dropped below
the preset alarm level. This alarm is only

available on units congured with P + I

control (mode 3).

Slave Fault

One of the 6 indicating faults has been de­tected in a slave unit.

Contactor Failed

Unit has tried to turn on but contactor has
not closed, or unit should be off, but con­tactor is still closed.

Alarm setpoint too close to control set­point

Humidier is powered but turned “off” and

the RH is below the alarm setpoint.

Sensor or wiring has failed

Review of the slave units is required to

determine specic fault conditions.

Failed contactor - It’s common to nd

metal chips or other construction debris
lodged in the contactor preventing proper
operation

Faulty control wiring.

Auxiliary contact dislodged from proper
position.

Faulty auxiliary contact

Installation with RDU’s--the jumper be­tween control terminal strip poles 1 & 2
needs to be removed.

1. Turn the humidier “on” to satisfy de­mand.

2. Adjust the low humidity alarm.

Repair or replace

Herrtronic® MD Series

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23

Installation, Operation, & Maintenance Manual

Cylinder Full Zero Current

Cylinder full condition is present but zero
amp draw is being sensed. Unit will con­tinue to operate.

Zero Electrode Current

The electrode current is zero and it should
not be.

Non-Zero Slowly Decreasing Current

The current is decreasing more slowly
than it should during any automatic drain.
The system will continue to operate but
maintenance is required.

Non-Zero Non-Decreasing Current

A worsening of the condition above. A
complete blockage has occurred.

Non-Zero Non-Increasing Amps

System is not detecting increase in cur-

rent draw during ll.

Air Flow / High Limit

Unit has detected loss of airow in air han­dling system or room distribution unit, or
the optional on/off high limit setting has
been reached

Cylinder Full

Unit has detected water level at the top of
the steam cylinder.

Humidity Sensor Failed

Only available on units congured with a

P+I control. The sensor has registered a
humidity reading of 100% of more, or 4%
or less for more than 5 seconds.

Repair or replace. To check the toroid,

Faulty toroid transformer or wiring

Loss of one leg of main power

Very clean water-less than 100 micromho

Faulty toroid transformer or wiring

Failed drain system (stuck open)

Failed ll system (stuck closed)

Excessively long cycle time (>150 sec­onds).

Defective drain system

Block drain valve or drain system

Failed drain valve or defective wiring

Faulty ll valve or wiring

Water supply is shut off

High limit setpoint has been exceeded at
high limit humidistat

Fan has stopped while there is still a de-

mand for humidication.

Insure proper wiring for both air ow

switch and high limit humidistat.

Failed blower or air ow switch in RDU. Repair or replace.

Low conductivity water supply – start-up
condition

Softened supply water

Overconcentrated water in cylinder caus­ing foaming

Approaching end-of-cylinder life

Failed humidity sensor or wiring

Position of humidity sensor too close to
steam discharge

measure the resistance of the toroid trans­former. It should be approximately 8.5
ohms (+/- 1.5 ohm).

Check main terminal blocks. If line voltage
is not present, check external fusing.

Contact your local water authority. If you
are on a well, a complete water analysis
should be performed. If you have any
questions about the analysis, contact the
factory.

Repair or replace. To check the toroid,
measure the resistance of the toroid trans­former. It should be approximately 8.5
ohms (+/- 1.5 ohm).

Repair or replace. Operate drain valve
with manual drain switch (Menu 5) to de­termine whether it is operating freely.

Repair or replace. Check that external ll

valve is open. Check that strainer is not
blocked. Check to see that 24 VAC is at

the coil of the ll solenoid.

.

Clean and/or replace as necessary. Check
for partial blockage of drain valve, drain
cup, or drain plumbing.

Repair or replace as necessary.

Repair or replace.Blocked strainer

Check air handling system.

.

Install electrode jumper wires if not al­ready connected ( See page 21).

See softened water operating parameters
in Fig. 30.

See hard water operating parameters in
Fig. 30 or 31.

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Herrtronic® MD Series

Installation, Operation, & Maintenance Manual

Communications Fault

A short has been detected in the RS-485
communications loop.

Green power lamp and LCD are not illu­minated.

Unable to turn unit on after pressing “on/
off” button

Water always draining when drain sole­noid is closed

Display shows erroneous number and
titles (such as “%*#~?/*@”)

Blown 24 VAC control fuse

Blown high voltage fuses

Main transformer failure

Incorrect voltage to primary side of trans­former

Obstruction keeping the drain solenoid
from closing

Maintenance is required.

Short in control wiring or microprocessor
board if fuse blows immediately.

Short in contactor or control wiring if fuses
blow as unit energizes contactor.

Short in ll valve or wiring if fuses blow
after unit is attempting to energize the ll

valve.

Short in drain valve or wiring if fuses blow
after unit has cycled and is now attempt­ing to energize the drain valve.

Spike in power supply.

Short in terminal blocks or contactor

Check for 24 VAC on secondary side of
transformer between X1 and X2.

If secondary side is insufcient and proper

voltage is being supplied to primary side
of transformer, replace transformer.

Conrm voltage supplied compared to tap

on transformer and data plate.
Measure AC voltage across the primary
of the transformer for supplied voltage

If insufcient, check path through terminal

blocks, contactor and fuses for a potential
drain.
If every point of connection within the

humidier reads the same insufcient

number, then the disconnect should be
checked.

Open door and press “on/off” button again.
If unit comes on, place 1 and 2 wires to the
opposite side of the door interlock switch.

Poles 1 & 3 on the controls terminal strip
need to be jumped.

Clean and/or replace.

Press reset button on the back of the PC
board

Check for proper ribbon cable connec­tions to LCD and PC board (see page 22,
Item E)

Replace ribbon connector, LCD and PC
board.

Herrtronic® MD Series

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25

Installation, Operation, & Maintenance Manual

Summary of Troubleshooting Tips for the Inputs and Outputs of the EST-1250 Circuit Board

Turn power ON to the unit (green power light should be ON) & verify proper sensor installation. If all of the 24 VAC inputs to the
circuit board are energized, but ANY of the outputs from the circuit board are NOT indicated, the circuit board may not be operating
properly.

1) Verify that these inputs to the circuit board are energized:

24 VAC Input to Board Source of 24 VAC Input to Board

At Connector J3 At Terminal Block
PIN 1, wire # 17 Terminal 10, wire # 17
PIN 4, wire # 18 Terminal 9, wire # 18
PIN 8, wire # 19 Terminal 8, wire # 19
PIN 10, wire # 20 Terminal 7, wire # 20
At Connector J5 At Terminal Strip
PIN 1, wire # 37 Terminal 3, wire # 16 (thru door interlock)
PIN 2, wire # 45 Terminal 2, wire # 45
At Connector J5 At Auxiliary contact
PIN 3, wire # 3 Wire # 3

2) Verify that these outputs from the circuit board are energized:

24 VAC Output from Board Function of 24 VAC Output from Board
At Connector J3
PIN 5, wire # 34 Energize contactor coil, wire # 34
PIN 9, wire # 23 Energize drain solenoid, wire # 23

PIN 11, wire # 13 Energize ll solenoid, wire # 13

DC Output from Board Function of DC Output from Board
At Connector J5 At Terminal Strip
5 VDC at PIN 5, wire # 5 5 VDC available at terminal #10, wire # 5
20 VDC at PIN 8, wire # 8 20 VDC to power sensors from terminal #7, wire # 8
5 VDC at PIN 9, wire # 9 5 VDC to simulate sensor input at terminal #6, wire # 9

Output to Unit Display
From Connector J4
Board generates clear and legible two line display instead of a single row of black or gray blocks.

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Herrtronic® MD Series

Installation, Operation, & Maintenance Manual

Inputs / Outputs of Terminal Strips and Terminal Block

Terminal Block
Position 1-6 24 RET (GND)
7-12 24 VAC
All twelve (12) positions should be utilized if the Room Dispersion Unit (RDU) is installed

RDU Terminal Strip – Connections to RDU only
Pole
1 24 RET (GND) (Always)
2 24 VAC Trigger (24 VAC when contactor is energized)
3 Line Voltage (Always)
4 Line Voltage (Always)
5 24 VAC Air (24 VAC when switch Proving Switch is closed)
6 24 VAC (Always)

Control Terminal Strip
Pole
1 24 VAC (Always)

2 Airow / High Limit input, 24 VAC for operation

3 External “Off”, 24 VAC for operation
4 Control input ground – Modulating and on/off
5 Control input signal – Modulating and on/off
6 +5 VDC
7 +20 VDC
8 Limit input ground - Modulating
9 Limit input signal - Modulating
10 +5 VDC
11 RS-485 Communication, Negative, Digital
12 RS-485 Communication, Positive, Digital

Figure 30

Hard Water/Softened Water*

(750-1000 Micromho)

Adjust Menu Items to These Settings

MDM MDS/

MDD

Cycle Time (Menu #3) 75 11 5

Low Drain Threshold (Menu #2) 88 84

Capacity Setpoint (Menu #2) 96 96

High Drain Threshold (Menu #3) 108 108

*Naturally soft water is less than 50 micromho.

Figure 31

Very Hard Water

(> 1000 Micromho)

Adjust Menu Items to These Settings

MDM MDS/

MDD

Cycle Time (Menu #3) 60 100

Low Drain Threshold (Menu #2) 91 86

Capacity Setpoint (Menu #2) 94 92

High Drain Threshold (Menu #3) 105 105

Herrtronic® MD Series

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27

Installation, Operation, & Maintenance Manual

NOTE

1. For On/Off (mode 1) units, a resistor (68.1 kohms) between poles 5 and 7 on the controls terminal strip is required.
(34.0 kohms for MDD units)

2. If more than one MDS, MDM or MDD are “networked” together, a resistor may be required in socket R28 on PCB.
(See pg.12)

Circuit Board: J1 Connector

PIN

Circuit Board: J5 Connector

PIN

4 Toroid Input, Non-polar
3 Toroid Input, Non-polar
2 RS-485 Communication, Positive, Digital
1 RS-485 Communication, Negative, Digital
5 Not Used

Circuit Board: J3 Connector

PIN
1 Power Input, 24 VAC
2 Power Input, 24 RET (GND)
3 Not Used
4 24 VAC, for contractor coil, (Always)
5 24 VAC, for contractor coil, switched
6 Alarm Output
7 Alarm Output
8 VAC, for drain valve, (Always)
9 24 VAC, for drain valve, switched

10 24 VAC, for ll valve, (Always)
11 24 VAC, for ll valve, switched

RIBBON CABLE
CONNECTOR

J4

SELECT
RESISTORS

2
1

RESET

Figure 32

SW7

SW5 SW6

11. Door interlock input, 24 VAC to operate

10 Air ow/High Limit input, 24 VAC to operate

9 Auxiliary contact input, 24 VAC when energized and 0

VAC when de-energized.
8 Cylinder Full input
7 +5 VDC
6 Limit input signal – Modulating
5 Limit input ground – Modulating
4 +20 VDC
3 +5 VDC
2 Control input signal – Modulating and On/Off
1 Control input ground – Modulating and On/Off

Circuit Board: J3 Connector

PIN

1-14 LCD, 2-Lines X 20 Characters, non-backlit

Microprocessor Board

J5

SW3

SW1

J5 MOLEX
CONNECTOR

RESET
SWITCH

RAM

EPROM

HEAT SINK

28 www.herrmidifier-hvac.com

SW4

CR4

R12

R16

R7

CR2

CR1

HIGH LIMIT RESISTOR

CAPACITY RESISTOR

CONTACTOR IND.

FAULT IND.

J1

11

SW2

R28

CR5

FILL VALVE IND.

DRAIN VALVE IND.

1

J3

J1 MOLEX
CONNECTOR

J3 MOLEX
CONNECTOR

Herrtronic® MD Series

Installation, Operation, & Maintenance Manual

Replacement Cylinders

MDS Parts List:

Item no. Description
EST-1002-4-1 Single Phase, 5-50 #/hr.
EST-1002-6-1 Three Phase, 5-50 #/hr. (shown)
EST-1002-6-2 Three Phase, 60-100 #/hr.

MDD Parts List:

Item no. Description
EST-1002-6-2 Three Phase, 110-250 #/hr.
(2) Tanks Required

Herrtronic® MD Series

MDM Parts List:

Item no. Description
EST-416-2 Single Phase, 5-15 #/hr. (shown)
EST-416-3 Three Phase, 5-30 #/hr.

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29

Installation, Operation, & Maintenance Manual

EST-1080

EST-076

EST-1060-3

EST-165

EST-1092

DRAIN KIT
ASSEMBLY

EST-1225-KIT

354537-001

DRAIN SUB­ASSEMBLY

354415-001

FILL SUB-

ASSEMBLY

GT-116

GT-118

GT-116

GT-153

FV-12 (INCLUDED w/4060)

FV-11 (INCLUDED w/4060)

PART OF 4060

121078-011

121078-011

EST-122-1

454320-001

Model MDS - Parts Schematic

EST-1127

4060

EST-1136

121800-001

265171-001

EST-1168

EST-1250

121800-001

EST-1136

EST-1127

354563-001

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Herrtronic® MD Series

Installation, Operation, & Maintenance Manual

120096-003

1845

254319-001

EST-117

EST-1016

254319-002

454317-001

EST-1123

CHART 1

CHART 2

454313-001

POWER DISTRIBUTION

MODEL NO.

MDS-3
MDS-6
MDS-7
ALL OTHER MDS UNITS DO NOT USE A POWER DISTRIBUTION BLOCK

MODEL NO.

MDS-7

ALL OTHER MDS UNITS USE EST-238 GROUND BLOCK

BLOCK P/N

EST-235
EST-236
EST-236

GROUND BLOCK P/N

EST-239

VOLTAGE

208/240
208/240
208/240

VOLTAGE PHASE

208/240

PHASE

SINGLE
THREE
THREE

THREE

OUTPUT
LBS/HR

40-50
60-80
90-100

OUTPUT
LBS/HR

90-100

208V: 80-100

EST-1409

EST-353

EST-105A

SEE CHART 1

SEE CHART 2

EST-109

or

EST-109-3

259097-001

or

255991-001

or

253402-002

EST-109-2

EST-122-1

155045-001

EST-120 (4A)

OR

158481-001 (6-1/4A)

MDS Parts List

HERRMIDIFIER PART NO. DESCRIPTION

EST-003B

EST-076

EST-105A
EST-109
EST-109-2
EST-109-3
EST-117
EST-120
EST-122-1
EST-165
EST-171
EST-235
EST-236
EST-238
EST-239
EST-353

EST-529C

EST-1016
EST-1060-3
EST-1080
EST-1092
EST-1123 265171-001
EST-1124-1
EST-1127
EST-1136

Cylinder Full Interface
Lock Washer, Stainless Steel
Toroid Transformer
Contactor, 3 Pole, 40 Amp
Auxiliary Contact
Contactor, 3 Pole, 65 Amp
Grommet, Steam Hose
Control Fuse, 4 Amp
Cabinet Lock with Keys
SS Hose Clamp, Steam Hose
Steam Hose
Power Distribution Block, 175A, 1PH
Power Distribution Block, 175A, 3 PH
Ground Block
Ground Block
Shorty Bushing, 7/8"

Quick Connect, Cyl Full Electrode
Hole Plug, Steam Outlet, 2 1/2"
"O" Ring
Electrode Knob
Drain Kit Assembly
Terminal Block, 12 Position
Terminal Strip, 4 Amp
Spacer, Nylon #6
Washer, Nylon #6

EST-1124-1

EST-003B

EST-1612

HERRMIDIFIER PART NO.

EST-1168
EST-1225-KIT
EST-1250

EST-1409
EST-1612
FV-11
FV-12
GT-116
GT-118
GT-153

1845
4060
120096-003
121078-011

121800-001

141622-001EST-354
155045-001
158481-001
253402-002
255991-001
259097-001

354415-001
354537-001

141622-001

141622-001

EST-354

454320-001

EST-354

DESCRIPTION

RIbbon Cable Assembly
Drain Reservoir Kit
Microprocessor Board, Provide Specific Model # and
Control Arrangement.
Universal Bushing
Marking Strip for EST-1124-1
Sleeve, Brass, 1/4" Compression
Brass Compression Nut, 1/4"
Celcon Compression Nut, 1/4"
Metering Fill Solenoid
Strainer
Door Interlock Switch
1/4" Comp. X 1/4" Comp. Brass Bulkhead Union
Hole Plug
Sealing Washer
KEP Nut, 4-40
High Voltage Fuse HolderHigh Voltage Fuse, 600 V
Fuse Holder
Control Fuse, 6-1/4 Amp
Control Trans, 208/230/240/460/480V Primary, 150VA
Control Trans, 208/230/380/460/600V Primary, 96VA
Control Transformer, 208/230/460V Primary, 100VA
LCD Display
Fill Sub-assembly
Drain Sub-assembly

Herrtronic® MD Series

www.herrmidifier-hvac.com

31

EST-1080

Installation, Operation, & Maintenance Manual

354415-003
FILL SUB-

EST-076

EST-165

ASSEMBLY

EST-122-1

EST-1060-3

354190-001

354561-001

EST-1092
DRAIN KIT
ASSEMBLY

EST-1225-KIT

EST-1127

EST-1127

354537-002
DRAIN SUB­ASSEMBLY

EST-1136

121800-001

EST-1168

121800-001

EST-1136

GT-116

GT-118

GT-116

GT-153

FV-12 (INCLUDED w/4060)

FV-11 (INCLUDED w/4060)

PART OF 4060

121078-011
121078-011

4060

265171-001

EST-1250

Model MDM - Parts Schematic

32 www.herrmidifier-hvac.com

Herrtronic® MD Series

Installation, Operation, & Maintenance Manual

EST-117

454194-001

1845

EST-1409

EST-353

EST-105A

EST-238

254319-003

155045-001

MDM Parts List

HERRMIDIFIER PART NO. DESCRIPTION

EST-003B
EST-076
EST-105A
EST-109
EST-109-2
EST-117
EST-120
EST-122-1
EST-165
EST-171
EST-238
EST-353
EST-354

EST-529C
EST-1060-3
EST-1080
EST-1092
EST-1123
EST-1124-1
EST-1127
EST-1136
EST-1168

Cylinder Full Interface
Lockwasher, Stainless Steel
Toroid Transformer
Contactor, 3 Pole, 40 Amp
Auxiliary Contact
Grommet, Steam Hose
Control Fuse, 4 Amp
Cabinet Lock with Keys
SS Hose Clamp, Steam Hose
Steam Hose
Ground Block
Shorty Bushing, 7/8"
High Voltage Fuse, 600 V
Quick Connect, Cyl Full Electrode
"O" Ring
Electrode Knob
Drain Kit Assembly
Terminal Block, 12 Position
Terminal Strip, 4 Amp LCD Display
Spacer, Nylon #6
Washer, Nylon, #6
RIbbon Cable Assembly

EST-120

EST-1124-1

EST-1123

EST-1612

HERRMIDIFIER PART NO.

EST-1225-KIT
EST-1250

EST-1409
EST-1612
FV-11
FV-12
GT-116
GT-118
GT-153
1845
4060
121078-011
121800-001
141622-001
155045-001
255991-001
259097-001
265171-001
354415-003
354537-002

EST-003B

EST-109

259097-001

or

255991-001

EST-109-2

141622-001

141622-001

EST-354

354190-001

EST-354

DESCRIPTION

Drain Reservoir Kit
Microprocessor Board, Provide Specific Model # and
Control Arrangement.
Universal Bushing
Marking Strip for EST-1124-1
Sleeve, Brass, 1/4" Compression
Brass Compression Nut, 1/4"
Celcon Compression Nut, 1/4"
Metering Fill Solenoid
Strainer
Door Interlock Switch
1/4" Comp. X 1/4" Comp. Brass Bulkhead Union
Sealing Washer
KEP Nut, 4-40
High Voltage Fuse Holder
Fuse Holder
Control Transformer, 208/230/380/460/600V Primary - 96 VA
Control Transformer, 208/230/460V Primary - 100 VA

Fill Sub-assembly
Drain Sub-assembly

EST-122-1

Herrtronic® MD Series

www.herrmidifier-hvac.com

33

BLK

27

YEL

0

120

ALTERNATE TRANSFORMER

WHT

TRANSFORMER LEAD

CORRESPONDING TO INCOMING

ALTERNATE CLASS 2

TRANSFORMER WITH

FLYING LEADS AND

CIRCUIT BREAKER ON

SECONDARY (24V)

MDS / MDM WIRING DIAGRAM

Installation, Operation, & Maintenance Manual

27

14

BLK

CIRCUIT

BREAKER

YEL/WHT

(24 VAC)

240

277

480

BRN

GRAY

ORG

(2A)

LINE VOLTAGE IS CONNECTED

TO FUSE 1. UNCONNECTED

TRANSFORMER LEADS MUST BE

SEPARATELY INSULATED.

FUSE 2

BLK

(TR)

BLK

29

BLK

30

SIDE

BLK

YEL/WHT

TERMINAL

BLOCK

(2A)

FUSE 1

(TL)

GND

L1

L2

POWER INPUT

L3

11

9

53 7

1

IF FUSE 3 IS MOUNTED ON TRANSFORMER,

WIRE 28 IS OMITTED AND WIRES 14, 27, &

TRANSFORMER

GROUND WIRE #153 IS NOT USED WITH ALTERNATE CLASS 2 TRANSFORMER

12

10

8

6

4

2

54

BLK

FUSE 3

BLK

(4 A FOR 100 VA)

28

54 CONNECT TO TRANSFORMER TERMINAL XF

(24 VAC)

X1

XF

0

208

BLK

GND

POWER DISTRIBUTION

BLOCK

NOTE:

POWER DISTRIBUTION BLOCK

NOT USED ON SINGLE

CONTACTOR UNITS.

BLK

(6 1/4 A FOR 150 VA)

153

14

X2

230

WIRE #32 CONNECTED

TO INCOMING LINE

31

BLK

BLK

BLK

BLK

WHT

(24 RET)

VOLTAGE LEG OF

GROUNDED

27

26

26

X3

480

TRANSFORMER

TO CHASSIS

V

W

X

WHT

FUSE 2

(TR)

BLK

BLK

WHT

TERMINAL

BLOCK

BLK

(2A)

30

BLK

O

TERMINAL STRIP 2

(RDU)

11

9

5 7

3

1

55

BLK

32

(2A)

FUSE 1

BLK

15

(TL)

BLK

29

BLK

BLK

36

M

BLK

N

6

5

4

3

2

1

12

10

6 8

4

2

CYLINDER FULL

INTERFACE

BLUE

46

BLK

35

RED

CYLINDER

24

FULL

40

39

1

2

AIR FLOW SWITCH

DOOR

TOROID

INTERLOCK

THIS WIRE NOT

BLK

(NO)

(COM)

WHT

RED

SUPPLIED ON

1 PHASE UNITS

42

BLUE

47

(OPTIONAL)

41

A

B

C

BLK

BLUE

BLUE

12

45

FILL

VALVE

42

BLK

41

BLUE

36

BLK

35

BLK

38

ORG

33

WHT

12

BLUE

17

BLK

18

BLUE

19

ORG

20

WHT

33

WHT

22

ORG

47

WHT

46

BLUE

21

WHT

25

BLK

2

1

ELECTRODE

L1

L2

L3

4

ORG

3

4

BLK

14

V3

VARISTOR

ORG

ORG

34

RED

BLK

T1

BLK

T2

BLK

T3

(1)

CONTACTOR

RED

38

3

BLK

BLK

25

RED

BLK

36

35

5

3

4

WHT

GRN

16

10

11

22

ORG

VARISTOR

POWER ELECTRODES

THESE WIRES NOT

USED ON SINGLE

CONTACTOR UNITS

BARE

- RS-485

+ RS-485

8

7

9

6

RED

9

11

10

12

A B

GRN

RED

WHT

8

6

7

TERMINAL STRIP 1

BLK

RED

WHT

43

5

44

+

-

CONTROLS

WHT

55

TERMINAL STRIP 4

BLK

54

2

1

TERMINAL STRIP 3

24VAC, 4 VA MAX.

REMOTE ALARM

RED

RED

49

48

J5

37

WHT

45

3

4

5

6

7

8

9

10

11

11

BLUE

10

RED

9

ORG

RED

7 8

WHT

GRN

RED

4

RED

WHT

GRN

BOARD PIN NUMBER

32 65

1

J3

13

WHT

20

23

19

49

48

34

18

21

17

DRAIN

VALVE

11

WHT

10

ORG

9

ORG

RED

7 8

RED

ORG

BLUE

4

32 65

WHT

BLK

BOARD PIN NUMBER

J1

11

10

V1

VARISTOR

V2

44

43

THESE WIRES NOT

USED ON SINGLE

CONTACTOR UNITS

ORG

M

N

O

9

6 875

RED

4

RED

32

WHT

BLK

51

BLK

BLK

BLK

BOARD PIN NUMBER

1 1

V4

VARISTOR

BLUE

52

G

BLK

T1

L1

L2

L3

H

BLK

T2

I

POWER ELECTRODES

BLK

T3

(2)

CONTACTOR

34 www.herrmidifier-hvac.com

Herrtronic® MD Series

Installation, Operation, & Maintenance Manual

MDS / MDM WIRING DIAGRAM

POWER INPUT

TRANSFORMER

0

GND

L1

L2

L3

BLK

FUSE 3

(4 A FOR 100 VA)

BLK

(6 1/4 A FOR 150 VA)

28

(24 VAC)

X1

230

208

GND

POWER DISTRIBUTION

BLOCK

NOTE:

POWER DISTRIBUTION BLOCK

NOT USED ON SINGLE

40

39

1

2

AIR FLOW SWITCH

DOOR

TOROID

INTERLOCK

THIS WIRE NOT

BLK

(NO)

(COM)

WHT

RED

SUPPLIED ON

1 PHASE UNITS

BLUE

47

(OPTIONAL)

42

41

A

B

C

BLK

BLUE

BLUE

12

45

FILL

VALVE

6

5

4

3

2

1

TERMINAL STRIP 2

(RDU)

27

BLK

11

9

26

WHT

5 7

3

1

TERMINAL

BLK

14

WHT

(24 RET)

TO INCOMING LINE

VOLTAGE LEG OF

GROUNDED

BLK

BLK

BLK

26

X3

480

TRANSFORMER

TO CHASSIS

V

W

X

BLOCK

WHT

55

CYLINDER FULL

INTERFACE

BLK

600

BLK

32

(2A)

(2A)

FUSE 2

FUSE 1

BLUE

BLK

46

15

(TR)

(TL)

BLK

29

BLK

30

BLK

BLK

35

BLK

36

M

BLK

N

BLK

O

153

54

BLK

380

WIRE #32 CONNECTED

BLK

31

41

BLUE

36

BLK

35

BLK

38

ORG

33

WHT

12

BLUE

12

17

BLK

10

6 8

4

2

RED

CYLINDER

18

BLUE

19

ORG

20

WHT

33

WHT

22

ORG

47

WHT

46

BLUE

21

WHT

25

BLK

2

1

24

FULL

ELECTRODE

L1

L2

L3

4

ORG

3

4

BLK

14

V3

VARISTOR

ORG

ORG

34

RED

BLK

T1

BLK

T2

BLK

T3

(1)

CONTACTOR

RED

38

3

BLK

BLK

25

RED

BLK

36

35

42

BLK

CONTACTOR UNITS.

3

4

WHT

GRN

16

11

22

ORG

VARISTOR

POWER ELECTRODES

THESE WIRES NOT

USED ON SINGLE

CONTACTOR UNITS

BARE

- RS-485

+ RS-485

8

5

7

9

6

RED

10

9

11

10

12

A B

GRN

BLK

RED

RED

WHT

WHT

8

6

43

7

5

44

CONTROLS

TERMINAL STRIP 1

-

WHT

55

+

TERMINAL STRIP 4

BLK

54

2

1

TERMINAL STRIP 3

24VAC, 4 VA MAX.

REMOTE ALARM

RED

RED

49

48

J5

37

WHT

45

3

4

5

6

7

8

9

10

11

11

BLUE

10

RED

9

ORG

RED

WHT

GRN

RED

4

RED

WHT

GRN

BOARD TERMINAL

3 5 6 7 8

2

1

J3

13

WHT

20

23

19

49

48

34

18

21

17

DRAIN

VALVE

11

WHT

10

ORG

9

ORG

RED

RED

62 3

ORG

5 87

BLUE

4

WHT

BLK

BOARD TERMINAL

1

J1

11

10

V1

VARISTOR

V2

44

43

THESE WIRES NOT

USED ON SINGLE

CONTACTOR UNITS

ORG

M

N

O

9

RED

4

RED

3 5 6 7 8

WHT

BLK

51

BLK

BLK

BLK

BOARD TERMINAL

2

1

V4

VARISTOR

BLUE

52

G

BLK

T1

L1

L2

L3

H

BLK

T2

I

POWER ELECTRODES

BLK

T3

(2)

CONTACTOR

Herrtronic® MD Series

www.herrmidifier-hvac.com

35

Engineered Humidification Systems

Herrmidifier

®

101 McNeill Rd. | Sanford, NC 27330

P: 800.884.0002 | F: 800.458.2379 | www.herrmidifier-hvac.com | [e-mail]

Form No. OM-93 04/13 ©Herrmidier 2013. All Rights Reserved.