Nortec NH Series - Manual (Page 48)

45 | Start Up
How the Humidifier Works
The NHRS is an isothermal humidifier that produces atmospheric steam at operational
pressures of -3 to +6 in. W.C. System operation is based upon regulating the operation of
Incoloy immersion resistive heating elements with pulse width modulation via contactor(s) or
optional solid state relay(s).
Start Up
1. Upon powering up the NHRS, a brief diagnostic process will be initiated, once this is
completed the humidifier will initiate a level sensing test. To initiate this test, it is
required that the operational water level be at level 1 or less. If the reservoir is above
this level the system will initiate a drain. If the water level is less than level 1, both
1.2 litre per min fill solenoids will be activated in order to recover water level quickly.
Once level 1 water level or greater is achieved, the system will fill with only a single
solenoid in order to increase the accuracy of the level sensing.
2. The level sensing test will perform a timed fill to water level 4 and initiate a drain
process to level 3. If both the fill and drain system successfully operate within the
allotted time requirements, the humidifier will assume automated operation.
Otherwise the system will generate a fault condition and display diagnostic
information.
Automated Operation
1. System operation is initiated by satisfying various control inputs that are specific to
the system configurations. Once the configured control inputs are satisfied, and
water levels are within operational requirements (level 1-4), steam production can
commence.
2. Steam production sequence will vary depending upon hardware configuration. Units
with the optional SSR relay kit should progress to step 2.2. Units with standard
contactors progress to step 2.1.
2.1. CONTACTORS: Once system demand exceeds 10% the contactors will close. The
contactor will pulse width modulate over 120 second cycles. At 11% demand the
contactor will be closed for 10 seconds and will increase the length of operation,
in relation to an increase in system demand in a linear fashion up to 98%
demand. At 98% demand and above the contactor will remain closed for the
maximum 120 seconds. Cylinders with multiple contactors will increment
operating time sequentially amongst all contactors in order to scale output to
demand.
2.2. SSR & CONTACTORS: Once system demand exceeds 4%, the contactors will
activate and pulse the SSR to modulate heat production up to 98% demand. At
98% demand and above the SSRs will remain constantly closed. For cylinders
with multiple solid state relays the system will increment operating time amongst
all SSRs sequentially in order to scale output to demand.
3. Once the contactors close, the fill system initiates pulse fill in order to anticipate
evaporation and maintain the operating water level. Operating pulses will increase as
the water level decreases, and conversely decrease the filling pulses as water level