Sequence Of Operation; Blowdown Calibration; Drain Rate And Blowdown Volume; Manual Steam Output Adjustment - Nortec GH Series Installation, User & Maintenance Manual

SEQUENCE OF OPERATION

Provided the necessary power, water, gas and
vent connections are completed, the unit is started by
the activation of the on/off switch located on the front
panel.
When the operating humidistat and safety controls
are closed, the ignition module will energize the igniter.
The hot surface igniter then heats up, and after about
seven seconds, the gas valve is energized. The
burner will then be lit and the igniter will shut off. If the
burner flame is not sensed by the flame sensor within
4 seconds, the gas valve will shut off and this cycle will
be repeated a maximum of three times. When the
humidity in the space matches the setting of the
operating controller, the burners will shut down and the
unit will remain idle until the next call for humidity.

BLOWDOWN CALIBRATION

The gas humidifier will periodically "blowdown"
water from the tank to reduce the concentration of total
dissolved solids that accumulate during long term
operation. Gas Humidifiers are shipped factory set at
maximum blowdown (approximately 20% of output).
This setting ensures that scale build-up will be
minimized for all water conditions. The amount of
blowdown is field adjustable. Two parameters will help
determine the proper blowdown setting of the Gas
-fired Humidifier
• Water hardness
• Silica content
Due to the wide range of water conditions found
throughout North America it is important that the
blowdown is set according to the local water
conditions. By water conditions we are referring to the
hardness of the water supplied to the humidifier. The
hardness is measured in grains per gallon. It is also
important to test for silica content. Silicates may cause
foaming and contribute to scale buildup in the
humidifier tank and float chamber. When excessive
GH 100
With
DWC
< 4 grains 8 (2.0)
4-10 grains 12 (3.0)
> 10 grains 16 (4.0)
These values are dependant of the water inlet pressures, gas inlet pressures, and steam output. These setting vary
from site to site. If your blowdown volume is different then the values given adjust the blowdown setting accordingly.
Consult factory for more details.
GH Blowdown Volume - l/hr (gal/hr)
GH 200
Without With
DWC DWC
4 (1.1) 16 (4.0)
6 (1.6) 24 (6.3)
8 (2 .0 ) 32 (8.5)
foaming occurs, an optional foam separator is
available from NORTEC.
If you are unaware of the hardness or silica
content of your water supply, there are many "do it
yourself" kits which can be purchased, or there are
several companies that will perform the tests for a
reasonable price. You can even contact your
municipality for your water condition.
It is possible to reduce this setting according to
observation and guidelines in the tables above . Also,
when high silica content has been identified, the
humidifier tank and float chamber will require
increased maintenance and the blowdown setting
should be increased to factory setting. In this case
silica content may determine the appropriate
blowdown setting.

DRAIN RATE AND BLOWDOWN VOLUME

When the drain pump is activated, the tank drains
at a rate of 8 gal/min (30 l/min). If the Drain Water
Cooler is in use, the actual drain rate of the unit
doubles. For details on total blowdown volume, refer
to the chart below.

MANUAL STEAM OUTPUT ADJUSTMENT

B Models

Manual rate adjustment for GHB units is
accomplished by rotating the output adjustment
selector that is located on the switch panel behind the
locked door panel. Rotate the knob labeled "Output"
clockwise to increase output and counter clockwise to
decrease output. See specifications for output values.

GHMC DISPLAY OPERATION

Refer to the GHMC Display Unit Operating
Instructions, Form #XX-274, for information on
programming and operating the display unit.
GH 300
Without With
DWC DWC
8 (2.0) 32 (8.5)
12 (3.0) 48 (12.7)
16 (4.0) 64 (16.9)
- 18 -
GH 400
Without With
DWC DWC
16 (4.0) 64 (16.9)
24 (6.3) 96 (25.3)
32 (8.5) 128 (33.8)
Without
DWC
32 (8.5)
48 (12.7)
64 (16.9)