Herrtronic
®
MD Series
I n s t a l l a t i o n , O p e r a t i o n , & M a i n t e n a n c e M a n u a l
24
www.herrmidifier-hvac.com
Cylinder Full Zero Current
Cylinder full condition is present but zero
amp draw is being sensed. Unit will con-
tinue to operate.
Faulty toroid transformer or wiring
Repair or replace. To check the toroid,
measure the resistance of the toroid trans-
former. It should be approximately 8.5
ohms (+/- 1.5 ohm).
Loss of one leg of main power
Check main terminal blocks. If line voltage
is not present, check external fusing.
Very clean water-less than 100 micromho
Contact your local water authority. If you
are on a well, a complete water analysis
should be performed. If you have any
questions about the analysis, contact the
factory.
Zero Electrode Current
The electrode current is zero and it should
not be.
Faulty toroid transformer or wiring
Repair or replace. To check the toroid,
measure the resistance of the toroid trans-
former. It should be approximately 8.5
ohms (+/- 1.5 ohm).
Failed drain system (stuck open)
Repair or replace. Operate drain valve
with manual drain switch (Menu 5) to de-
termine whether it is operating freely.
Failed fill system (stuck closed)
Repair or replace. Check that external fill
valve is open. Check that strainer is not
blocked. Check to see that 24 VAC is at
the coil of the fill solenoid.
Excessively long cycle time (>150 sec-
onds).
.
Non-Zero Slowly Decreasing Current
The current is decreasing more slowly
than it should during any automatic drain.
The system will continue to operate but
maintenance is required.
Defective drain system
Clean and/or replace as necessary. Check
for partial blockage of drain valve, drain
cup, or drain plumbing.
Non-Zero Non-Decreasing Current
A worsening of the condition above. A
complete blockage has occurred.
Block drain valve or drain system
Repair or replace as necessary.
Failed drain valve or defective wiring
Non-Zero Non-Increasing Amps
System is not detecting increase in cur-
rent draw during fill.
Faulty fill valve or wiring
Repair or replace.
Blocked strainer
Water supply is shut off
Air Flow / High Limit
Unit has detected loss of airflow in air han
-
dling system or room distribution unit, or
the optional on/off high limit setting has
been reached
High limit setpoint has been exceeded at
high limit humidistat
Fan has stopped while there is still a de-
mand for humidification.
Check air handling system.
Insure proper wiring for both air flow
switch and high limit humidistat.
.
Failed blower or air flow switch in RDU.
Repair or replace.
Cylinder Full
Unit has detected water level at the top of
the steam cylinder.
Low conductivity water supply – start-up
condition
Install electrode jumper wires if not al-
ready connected ( See page 21).
Softened supply water
See softened water operating parameters
in Fig. 30.
Overconcentrated water in cylinder caus-
ing foaming
See hard water operating parameters in
Fig. 30 or 31.
Approaching end-of-cylinder life
Humidity Sensor Failed
Only available on units configured with a
P+I control. The sensor has registered a
humidity reading of 100% of more, or 4%
or less for more than 5 seconds.
Failed humidity sensor or wiring
Position of humidity sensor too close to
steam discharge
