Nortec MES-U User Manual

MES-U Electrode
Steam Humidifiers

Installation, Operation,

Maintenance, Spare Parts, and

Exploded Views Guide

IMPORTANT: Read and save this guide for future

reference. This guide to be left with equipment owner.

Form 03-111 Rev. 1

Table of Contents

INSTALLATION 1

RECEIVING EQUIPMENT..............................1

–

PRINCIPAL OF OPERATION ............................1

–

WATER SUPPLY AND PLUMBING ..........................2

–

WATER CONNECTION .............................2

–

START-UP AND OPERATION ............................2

–

CAPACITY ADJUSTMENT ............................3

–

CYLINDER REPLACEMENT.............................3

–

WHEN TO REPLACE THE STEAM CYLINDER ...................3

–

REMOVING THE OLD CYLINDER .........................3

–

INSTALLING THE NEW CYLINDER ........................4

–

MAINTENANCE 4

EXTENDED SHUTDOWN..............................4

–

TROUBLESHOOTING 4

– TERMS USED ..................................4

– STARTING POINT.................................5

– PHYSICAL DIMENSIONS DIAGRAM .........................7

– WIRING DIAGRAM ................................8

– SPARE PARTS LIST................................9

– EXPLODED VIEWS DIAGRAM ...........................10

INSTALLATION

2

S

RECEIVING EQUIPMENT

Figure #1

Operation Schematic

1. Check packing slip to ensure ALL material has
been received.

2. Inspect box for damage and note on shipping
waybill accordingly.

3. After unpacking, inspect unit for damage and if
damage is found, advise shipper as soon as
possible.

4. Inspect unit (humidifier) to ensure it is the correct
model, phase, and voltage. If any are incorrect,
advise the factory or your local representative
immediately.

NOTE: All products are shipped on an F.O.B.

factory basis. Any and all damage, loss, or breakage
claims are to be made directly to the shipping
company.

The NORTEC MES-U electrode humidifier is the

culmination of many years of research and
development in the electrode humidifier industry. This
unit has been built by skilled craftspeople and
thoroughly tested before shipment and should, if the
following instructions are observed, provide many
years of trouble-free operation.

FOR HUMIDIFIERS INSTALLED IN THE CITY

OF LOS ANGELES: A city of Los Angeles approved

spring-loaded double ball CHECK VALVE should be
supplied and installed by the contractor on each of the
potable water inlets to each humidifier.

Recommended valve manufacturer: Watts

Regulator (phone [phone]), model #7, size 3/8”
NPT inlet and outlet.

CONDENSATE RETURN

(OPTIONAL)

FILL
CUP

1. INLET CHAMBER

. FILL CHAMBER

3. WATER OVERFLOW
CHAMBER (SAFETY DRAIN
IN CASE OF FILL VALVE/
CONTROL BOARD FAILURE)

STRAINER

TAP

WATER

SUPPLY

FILL

VALV E

CONNECTION

1

DRAIN

1” AIR
GAP

3

2

DRAIN
VALV E

DRAIN CANAL

(OPEN TO ATMOSPHERE)

STEAM HOSE

ELECTRODE

CYLINDER

DRAIN
PAN

An electronic timer uses the rate of amp fall to
determine the water level. The objective is to
concentrate current-carrying minerals in the cylinder
so that a smaller volume of water is required to
produce the rated steam output.

This achieves the longest life for the disposable
cylinder because of minimal electrode coverage and
use of less energy because the high concentration
allows a minimal drain rate.

Each drain line from these humidifiers shall be
routed, without dips or sags, to terminate above the
flood level rim of a City of Los Angeles approved
indirect waste receptor.

No combustible materials shall be placed in the
duct and/or the air plenum.

When 90% F.L.A. is reached, the fill valve will
open refilling cylinder to 110% F.L.A. On occasion,
the drain valve will also come on if water level is too
low, indicating too high a concentration and the
requirement for a dilution of the water in the cylinder.

If the water reaches top of cylinder before 110%
F.L.A., the fill valve shuts off via the sensor and
fill-boil-fill-boil cycle continues, cycling off the red high

PRINCIPAL OF OPERATION

water sensor light until the concentration becomes
high enough to reach 110% F.L.A. The above

When the humidistat calls, the cylinder fills to

described control process will then take over.

110% of the Full Load Amperage (F.L.A.) or to the top
of the cylinder, whichever comes first. See Figure #1.

If it reaches 110% F.L.A. the water heats and boils

away to a level giving 90% F.L.A.

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WATER SUPPLY AND PLUMBING

n

1. The orifice in the fill valve is sized for an extended
water pressure range of 30 to 85 psi.

2. For water pressure between 15 and 30 psi, notify
the factory and the next larger size fill valve will be
supplied.

for water pressure from 30 to 85 psi and are
protected by the built-in strainer.

4. For inlet water pressure outside this range, the
factory should be contacted. (See Water Supply
and Plumbing section of this manual.)

START-UP AND OPERATION

3. For cases below 15 psi, notify the factory and a fill
valve with an oversized orifice will be supplied.

4. For cases above 85 psi, install a pressure
reducing valve in the water feed line to the unit.

5. With extremely dirty or muddy water sources, e.g.,
some well sources, ensure proper filtration by
adding an external filter to the water line entering
the unit. (Consult factory for accessories such as
filters.)

6. DO NOT use completely demineralized water with
this unit as it is the minerals that allow the
electrode principle to work.

7. DO NOT use a hot water source as it will cause
deposits that will eventually block the fill valve
orifice.

WATER CONNECTION

Figure #2

Bottom View of MES-U Unit

3/8" Cold Water

Olive Connection

Check to see that the unit is securely mounted on
a level surface with the proper drain and water supply.
Check for correct voltage with appropriately sized
service. Check that the steam distributor, steam
supply hose, and condensate line are correctly
installed and routed back to the unit. Ensure that the
external control humidistat is located in an area to
properly sense the relative humidity to be maintained
by the humidifier, and that the interconnecting low
voltage wires between the humidistat and the unit’s
control terminal strip are in accordance with the wiring
diagram.

Check all electrical connections for wires which
may have become loose in shipping. Components
damaged due to loose connections are NOT under
warranty.

Check electrode plugs to ensure they are pressed
firmly onto the electrode pins. Important: Loose
connections will cause overheating of the cylinder
plugs, possibly melting the plugs and/or cylinder.

Open the isolating valve in the feed water line to
the unit.

Make sure the humidistat is set high enough to call
for humidification.

7/8" Drain
Connectio

Use 7/8" I.D. Hose From Factory

A copper compression olive type coupling for 1/4"

1.
O.D. soft copper tubing is provided with unit and
requires no soldering for the water connection to
the unit. See Figure #2.

2. An isolating valve should ALWAYS be placed in
the feed water line allowing service of the fill valve.

3. Each unit is fitted with a fill solenoid valve located
on the base drain pan. Flow orifices are designed

Turn on the main disconnect in the primary service
feeding the unit and check that unit has power at the
primary terminal block.

PUSH THE AUTO ON/OFF/DRAIN SWITCH TO
“ON”.

Water will start to enter the cylinder through its
bottom port and rise in the cylinder to a point
determined by the solid-state control circuitry.

It is not unusual upon initial start-up for the
water to fill the cylinder and cycle on the red high
water sensor light.

The red light simply acts as a safety to shut off the
fill valve and prevent over-filling. With the red light on,
the water in the cylinder will continue to heat and, after
a few minutes, start to boil. After the boiling action of
the water has lowered the water level below the
sensor at the top of the cylinder, the red light will go

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out and the fill solenoid will again open until the
cylinder is again full.

This cycling of the red light and fill valve will
continue until the unit’s full output capacity is reached
after which the water level will automatically lower
itself in the cylinder. (The increased concentration
allows for lower electrode coverage while maintaining
the same output.) When a stabilized condition is
reached the water will be boiling close to the cylinder
seam level. The solid state circuitry will maintain the
proper concentration in the cylinder by introducing
short drains only when necessary.

cylinder is completely used as indicated by the red
high water sensor light illuminated on the cabinet.
When this condition is reached, a new replacement
cylinder is to be installed.

NOTE: Red light may come on during initial
start-up but does not mean cylinder replacement. See
Start Up and Operation section of this manual.

Consult factory or agent for replacement. Quote
the cylinder model from the white 3-digit label on the
cylinder or quote model, voltage, and serial number
from unit specification label.

If the cylinder is manually drained the above

process will repeat itself.

Low Water Conductivity

Should normalization of the unit be required
immediately after start-up, the installer may speed up
the process by artificially increasing water conductivity.
During a fillcycle, the installer should dissolve half a
teaspoon of table salt (no more) in a cup of water and
add it to the cylinder by means of the fill cup attached
to the plumbing section.

Open the plumbing compartment and add salt
solution through cylinder outlet. Excessive amounts of
salt will result in erratic operation of the unit; however,
normalization of the unit will occur automatically
through the solid-state control sequence.

CAPACITY ADJUSTMENT

Figure #3

Adjustable Pot

WHEN TO REPLACE THE STEAM CYLINDER

The steam cylinder is disposable and must be
replaced at the end of cylinder life. Cylinder life is
dependent on water supply conditions and humidifier
usage. Failure to replace the cylinder at the end of
cylinder life may result in unit damage. NORTEC is
not responsible for any damages resulting from, or
attributable to, the failure to replace a used cylinder
(see Manufacturer’s Warranty).

Figure #4

Cylinder Removal

Adjustable
Capacity Pot

The MES-U series of humidifiers come with
adjustable capacity (AC) PC boards. These boards
have a pot labeled 20 to 100%. See Figure # 3.

CYLINDER REPLACEMENT

After an extended period of operation, in
accordance with life expectancy information, the

REMOVING THE OLD CYLINDER

n

See Figure # 4.

1. Turn off the water supply to unit.

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