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Table 26 Humidifier—steam generator troubleshooting
Symptom Possible Cause Check or Remedy
False canister full
indication
Foaming
Check drain valve to ensure that it drains freely. Check
and replace if defective.
Check water supply. If commercially softened,
reconnect to raw water supply. If connected to hot
water reconnect to cold water.
Main 24 VAC fuse or
circuit breaker trips
Shorts or loose connections Check the wiring connections of the 24 VAC circuit.
Faulty circuit board Replace the circuit board.
Unit ON, humidifier will
not operate
Humidifier not receiving power
Verify that RUN/DRAIN switch is in the RUN position.
Check fuses or CBs and replace or reset if necessary.
Make sure molex connector is securely plugged into
circuit board and that no wires art loose.
Contactor pulled in, but
no water enters
canister
No water available to unit Check external shut-off valves.
Clogged fill line strainer Clean or replace fill line strainer.
Wiring breaks or loose connections Check for faulty wiring and loose connections.
Faulty circuit board Replace circuit board.
Water enters canister,
but canister full circuit
activates at a low water
level
Foaming Check drain valve and water supply.
Water enters canister,
but canister full circuit
activates at a low water
level
Canister interface connections
incorrect
Check connection on component plate in humidifier
cabinet Terminal #1 on the square block interface
device must be connected to L2 of the power terminal
block. L2 must also be connected to the electrode
closest to the steam outlet port.
Verify that the red wire from terminal #2 on the
interface connects to the red top terminal on the
canister. This is the one farthest from the steam outlet
port and is the high water sensor probe.
Full isolation has broken down
Remove red canister full wire from canister. If normal
operation resumes, canister must be replaced.
Remove the wire from terminal #3 on the interface. If
normal operation resumes, canister full interface must
be replaced.
Drain assembly not operating freely Check and replace coil or valve if necessary.
Faulty circuit board Replace circuit board
Canister fills but
overflows
Canister full circuit does not activate
Check wiring of canister full interface. Replace circuit
board.
Humidifier contactor is
not pulled in (to reset,
de-energize control
unit)
Cylinder full. Interface activated.
See similar symptoms above. Canister expired.
Replace canister.
Problem with fill water system
Water supply is not on. Fill valve problem. Drain valve
stuck open.
Red LED on humidifier
control board is on.
Humidifier contactor not
pulled in (to reset, de-
energize control circuit)
Humidifier amps reached 138% of full
load
Canister expired. Replace canister. DIP switch
settings changed with water in canister. Drain canister,
call Liebert service.
Humidifier fill valve stuck open; check valve. Water
conductivity too high; check water conductivity/quality.
Contact Liebert service.
DIP switches set incorrectly. Refer to Circuit Board
Adjustments on page 62
Mineral deposits obstruct drain valve
Check drain valve for obstructions and clean if
necessary.
Faulty solenoid Check for magnetic field at coil.
Faulty circuit board Replace circuit board.