HM700A1000
HM700 Faults
The self-diagnostic system built into the HM700 is continually
monitoring the operation of the humidifier. When an abnormal
condition occurs that cannot be self-corrected by the software
the HM700 will turn off power to the cylinder, drain the
cylinder, and annunciate the fault using the yellow status LED.
LED Flash Sequence
To differentiate between different fault conditions the yellow
LED is flashed in different sequences. Table 8 lists the fault
sequences that can be displayed, their meaning, possible
cause and suggested corrective actions.
Clearing a Fault
p
Check the flash sequence against the list of fault messages
and take any necessary actions to correct the cause(s) as
outlined in Table 8 on page 22.
p
Power cycle the humidifier with the On/Off switch waiting
10 seconds between turning it off and on.
Table 8. Troubleshooting HM700 Faults.
Yellow
LED
Symptom
Cause
Corrective Action(s)
1 flash
Excess Current
Current has
exceeded 130% of
max
Drain blocked water over concentrated Clean the drain line
Drain solenoid not energized, water
over concentrated
Check and correct wiring to drain valve.
Filling too fast, fill valve damaged and
leaking
Replace the fill valve
Filling too fast, wrong fill valve
Fill valve may be defective - replace if necessary
Water supply too conductive
a) Change the water supply
b) Contact Honeywell representative for recommendation
Humidifier short cycling
a) Check if high limit or other On/Off control is cycling
On/Off in less than 5 minutes. Check location and setting
of high limit.
b) Reduce the output by turning down the potentiometer
Wrong cylinder installed
Install correct cylinder model
Cylinder Spent but not detected by
software
Replace the cylinder (see maintenance chapter)
Condensate from other source
Remove condensate returns other than from steam line.
Back pressure
Eliminate back pressure
2 flashes
No Current
Fill valve activated
for long time but
high water level not
reached.
Fill should be faster
than 1
o
per minute.
Drain valve leaking or stuck open
Clean drain valve or replace (see maintenance chapter)
Water shut off valve closed
Open shut off valve
Fill Valve strainer blocked
Clean out strainer on fill valve inlet.
High system back pressure
a) Check for kinked hose
b) Check for proper condensate removal (see
installation)
High water sensor not connected
Check that cylinder plug with white marker is connected
to short electrode with a plastic well around it and to
control board.
Low water conductivity
a) Check if potable water supplied to unit, not treated
water (RO or DI).
b) Check conductivity of water. If less than 150 S, add
1/4 teaspoon of salt to fill cup and restart unit.
3 flashes
No Current, High
Water
Water level at top of
cylinder with no
current
Primary wire not looped through
current transformer.
Rewire primary wire through current transformer.
High water sensor plug is on an
electrode pin.
Install high water senor plug on cylinder pin with shroud
around it.
Cylinder plugs installed incorrectly
Check that cylinder plugs colors match markers next to
electrodes on cylinder and that white marked cylinder
plug is connected to short electrode located in plastic
well.
4 flashes
Cylinder Spent
Electrodes covered
with scale.
Cylinder electrodes are covered with
scale and humidifier cannot meet
demand
Replace cylinder with same model number (see
maintenance chapter).
