Armstrong World Industries 6100 - Manual (Page 17)

17
Principle of Operation
The HumidiClean humidifier converts ordinary tap water or purified water to steam for distribution
to raise the relative humidity level. The demand for humidity is sensed by a humidistat or sensor
which sends a control signal to the HumidiClean. The HumidiClean is connected to the power
supply (208, 220/240, 380/400, 480 or 600 Vac) through a separate circuit breaker supplied by the
customer. When power is initially supplied to the unit from the circuit breaker, the LCD will display
“ARMSTRONG HC6000”. The “POWER” LED will come on and the unit’s fill valve solenoid is
energized to allow water to enter the tank at a rate of 1.2 L/min (.31 GPM) (HC-6500/6700 fill rate is
3.735 L/min (1 GPM)). Note: When unit is turned on the drain valve will energize for 6 sec. or until
water level drops below the high water probe. If water level in tank is above the low water level
switch, assuming the air proving switch is close, the high limit humidity switch is closed and the unit
status is ‘STEAM GEN’, the heating elements will be activated.
The water fill solenoid continues to be activated until the water level in the tank has energized the
high water switch. Note: If fill or drain valves are not energized when power is first applied, check
LCD for diagnostic code. See DIAGNOSTICS section. The heating elements will remain on to preheat
the water inside the tank until the temperature of water has reached the aquastat set point. During
this preheat cycle the amperage draw of the tank can be checked with a clamp on amp meter. The
amperage draw on all high voltage wires connected to the main power supply terminal block should
correspond to the value on the nameplate. If aquastat has been disabled, the humidifier will go into a
3 minute warm-up once the water hits the low water probe.
After the heat-up time, the HumidiClean will continue to produce steam based on the demand signal,
read from the humidistat or calculated by reading the relative humidity and setpoint. If the demand
signal drops below 2% or the high limit/sail switch circuit opens, the contactor(s) will open and the
unit status will be “IDLE”. Note: If the humidifier shuts off due to low humidistat demand, a demand
signal of 4% or greater is needed to re-initiate “STEAM GEN.” If all the signals are consistent as stated
above, HumidiClean will produce steam continuously and refill the tank with water when the low water
level is reached. These fill intervals will operate based on modulating fill settings in software.
Power to the heating elements is switched on and off by the triacs in the power module to achieve
a modulating output based on the demand signal. The triac utilizes a 1/2 second cycle time. For
example, with a 50% humidistat demand signal the triacs would be on for 1/4 second and off for 1/4
second. If the triacs are fully on, the green “SIGNAL” LED on the power module will be on constantly.
When the triacs start to modulate (switch power to the heating elements on and off) the LED will show
the triac on condition and will appear to flicker or blink.
As HumidiClean continues to produce steam, the unit will accumulate and memorize the heating
element active time for the purpose of defining a drain cycle and service life (this memory is not
affected by power outages). When the HumidiClean heating elements have been on for the drain
frequency setting, the unit activates the drain and fill solenoids and begins draining the tank. The tank
will drain with the water being tempered from an activated water fill solenoid. The drainage from the
tank will pass the low water switch, opening the switch and shutting off power to the heating elements.
The drainage from the tank should not exceed 70°C (158°F). The drain cycle is controlled by the user
inputted values in the operation setup menu. Once the unit has timed out of the drain cycle and all of
the switches are still in position to generate steam, the water fill solenoid switch is activated to fill the
tank and the cycle starts over again.