Nortec NH Series - Manual (Page 49)

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increases. This allows the humidifier to continuously evaporate without interruption
and prevents larger influxes of cold water that may otherwise interrupt system
operation by cooling the boiling chamber.
System Drains
1. System operation will continue in this state until the timer controlled flushing
(determined by the S1 dial selector switch on the processor board) is achieved. When
triggered, steam production will continue without interruption and the system will initiate
a drain of one water level.
2. The timer controlled flushing is based upon system operating at 100% capacity.
Operating at a lower system capacity will extend the drain interval by the factor of the
reciprocal of system demand (averaged for the length of the flush timer) to the flush
timer.
3. With very low demand this method can lead to exceedingly long intervals between
system flushes. In order to prevent the drain interval from becoming excessively long, a
function is used to limit maximum wait time before initiating the drain procedure. This
roughly equates to preventing the drain interval from exceeding 10 x the Flush Timer
setting.
4. Once triggered, the system will wait for a minimum water level of three, so as to not
interrupt steam production. If the system drain is triggered by the maximum wait time
the system will fill to level four and then evaporate to level three prior to draining. If the
level requirement is not achieved the filling pulses of the fill valve will be extended in
order to increase the water to levels permissible of initiating the system drain. Once
complete the fill valve operation will resume normal pulse control.