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PROCEDURES AND TERMS USED IN
DIAGNOSING
PRINCIPLE OF OPERATION
The conductivity of the water within the cylinder
must be controlled in order for the humidifier to
function properly. The fill and drain rates must be
maintained. Filling too quickly can cause over-amping
and automatic shutdown or blown fuses. Filling too
slowly can cause insufficient steam output and
foaming. Water supply pressure should be between
25 and 110 psig. Draining too slowly can cause
over-concentration and malfunction due to foaming.
These are just some examples of what can go wrong if
the fill and drain rates are not maintained.
FILL RATE
Fill rates of suspect units should be checked. Fill
rates should measure nominally at 1" to 1-1/2" of
vertical rise in water level in the cylinder in one minute.
Clogged fill valve will cause lower fill rate. The fill
valve strainer is removable and can be cleaned.
DRAIN TIME
Manual drain time of a half full cylinder takes
approximately 25 seconds.
If time measurements are longer, repeat with the
external drain disconnected (and draining into a pail)
to verify that the external drain is impeding flow. If it
still does not drain, check for a clogged strainer or
drain.
A clogged strainer or drain valve will cause
shortened cylinder life. Determine what caused the
strainer or drain valve to clog in the first place.
Do not assume that if a strainer and/or drain valve
is clogged that it is to blame. If the external drain has
been impeding flow then waste accumulates resulting
in a clogged strainer or clogged drain.
Clean the drain valve and install a fresh cylinder.
Then measure the manual drain time with and without
the external drain connected. Is the external drain
impeding flow? NORTEC recommends an open
external drain line. See the Installation section of this
manual.
RATED AMPERS
This refers to amps listed on the humidifier
specification label.
SHORT CYCLING
When the ‘on time’ of the humidifier is less than
ten minutes upon a call for humidity. To correct short
cycling, all humidifiers have a capacity adjustment
which allows the output of the humidifier to be reduced
as low as 25% of rated output, thus extending the ‘on
time’ required to maintain output. Excessive short
cycling may cause higher water conductivity (mineral
content) than designed for the unit.
FOAMING
A phenomenon which can occur in water when
impurities, already in the water, reach an excess
concentration as result of boiling away pure water and
the continued boiling action agitating the contained
water. The humidifier electronics are designed to
prevent this occurrence although in extreme cases
water will foam with little concentration, making it
necessary to have the drain time of the water,
contained in the cylinder, increased. Foaming is
normally caused by short cycling, a restricted drain, or
back pressure. The foam, generated in these
instances, is conductive and may lead to a false full
cylinder indication if the level of the foam approaches
the top of the cylinder.
BACKPRESSURE
Restriction of steam flow caused by improperly
sloped steam lines, elbows changing the direction of
the steam flow from horizontal to vertical without a
condensate drain leg, and any plumbing detail allowing
the accumulation of condensate.
MONITORED LEG
Refers to the primary wire, to the cylinder, which
loops through the current sensing device on the main
PCB. This wire is terminated at the red cylinder plug
at the cylinder.
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