Honeywell Home HM750A1000 Instructions D'installation page 25

HM750 Faults
The self-diagnostic system built into the HM750 is
continually monitoring the operation of the humidifier.
When an abnormal condition occurs that cannot be self-
corrected by the software, the HM750 will turn off power
to the cylinder, drain the cylinder, and annunciate the fault
using the yellow Service LEDs.
LED Flash Sequence
To differentiate between different fault conditions, the red
Fault LED is flashed in different sequences. The table
below lists the fault sequences that can be displayed, their
meaning, possible cause(s), and suggested corrective
actions.
Service LED Symptom
Cylinder Cylinder reaching
flashing end of life.
Cylinder Cylinder end of life. Normal operation.
solid
Fault 1 flash Excess Current
Current has
exceeded 130% of
max
Fault 2 Fill/Drain Error
flashes
Table 7. Troubleshooting HM750 Faults.
Cause
Normal operation.
Drain blocked, water over
concentration
Drain solenoid not energized, water
over concentrated
Filling too fast, wrong fill valve
Water supply too conductive
Cylinder spent, but not detected by
software
Back pressure
Drain valve leaking or struck open
Water shut off valve closed
High system back pressure
High water sensor not connected
Low water conductivity
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Clearing a Fault
• Check the flash sequence against the list of fault
messages and take any necessary actions to correct the
cause(s) as outlined in the below table.
• Press and hold the Power/Drain button for 5 seconds.
The humidifier will begin to drain and, when drained,
will power off. Press the Power/Drain button again at
this time to turn the humidifier back on again. The
humidifier will perform a normal start-up as if it were
the first power up.
Corrective Action(s)
None.
Replace cylinder.
Clean the drain line.
Check and correct wiring to drain valve.
Fill valve may be defective – replace if necessary.
Ensure water supply conductivity is within
specification 125-1200 μS/cm
(microsiemens/cm).
Examine the cylinder for excessive scale.
Eliminate back pressure by ensuring steam line
has no low points (where condensate might
accumulate), or steam line kinks.
Clean drain valve or replace.
Open shut off valve.
Eliminate back pressure by ensuring steam line
has no low points (where condensate might
accumulate), or steam line kinks.
Check the cylinder plug with orange cable is
connected from the short cylinder electrode with
a plastic shroud to the control board.
a. Check if potable water supplied to the
unit, not treated water (RO or DI).
b. Check conductivity of water. If less than
150 μS, add 1/4 teaspoon of salt to cyl-
inder and restart unit.
HM750A1000
33-00289EF—05