Nortec NHDI - Manual (Page 14)

OPTIONAL MODULATION (CONTINUOUS
CONTROL) PACKAGES BY NORTEC
1. Modulation (continuous control) “packages”
are offered as accessories by NORTEC.
Power supply comes from inside NHSC /
NHDI humidifiers.
2. NORTEC provides the humidity set point
circuitry and sensor(s) for wall or duct
mounting or both as pre-selected when
ordering the option. NORTEC offers several
packages for NHSC / NHDI Series humidifiers.
Wire according to NORTEC supplied external
wiring that comes with each optional
modulation package.
3. Optional modulation packages without
modulating safety high limit can use on-off
safety high limit. Refer to on-off controls
section.
4. All versions can use on-off safety air proving
switch. Refer to on-off controls section.
OPERATION
INTRODUCTION
The NORTEC NHSC Series humidifier is a
completely new design based on up-to-date
technology. The NHSC is designed to provide clean
steam humidification at an economical price.
The NHSC uses a micro-computer control system
for greater flexibility. The NHSC has a liquid crystal
display (LCD) to indicate system messages and
display RH.
LAYOUT AND FUNCTION
The NHSC humidifiers consist of a plumbing and
an electric compartment. In every case there is at
least one steam distributor (SD) for installation in air
ducts or blower packs (remote mounted: RMBP) for
direct space humidification.
Water enters the steam cylinder through the
bottom via the fill cup assembly when the 24 volt fill
valve solenoid is energized. The water is heated via
electric element and produces sterile steam for
distribution into the air.
Primary electric power is applied to the heating
elements in the steam cylinder when the on/off switch
is pushed on and all control options are calling. A
primary to 24 volt step-down transformer provides
power to the contactor holding coil(s) via the main
control board. The humidifier’s operating status is
reported to the user by the green, red and yellow
indicator lights on the front of the unit.
The prerequisites for getting power and water into
the steam cylinder are as follows:
- On/off switch must be switched on.
- control circuit 8-10 must be made.
- door interlock switch must be made (interlock switch
can be pulled out to operate unit).
- Modulating signal must be calling.
- Internal safeties must be made over temperature
switch and ground fault.
LEVEL REGULATION
The water level in the steam tank is continuously
monitored with the level unit.
The unit pulse fills based on steam production.
The pulse filling in the unit varies depending on the
water level detected by the float chamber.
One magnetic float monitors five different water
levels in the float chamber. The second float ensures
the water level is always above the heating elements.
The pressure equalizing pipe between the steam
connection and the level unit ensures that the water
levels are the same in the steam tank.
- 11 -