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506746−01 05/12
Troubleshooting
Problem
Causes
Solutions
The humidifier does not turn on
1. No electrical power.
2. On/off switch of the humidifier in position O"
(OFF).
3. Control connectors improperly connected.
4. Power source failure; blown fuse; tripped
breaker.
5. Transformer failure.
1. Check the safety devices upstream from the humidifier and
the presence of power.
2. Close the switch on the panel: position I" (ON).
3. Check that connectors are properly inserted in terminal
block.
4. Check the power source; check condition of fuses; check
for tripped breaker.
5. Check for proper voltage across 24VAC and GND on
control. If no voltage present, replace controller.
The humidifier does not start
operation
1. Remote ON/OFF contact open.
2. The humidistat has not been connected
correctly.
3. Humidistat failure.
4. Control signal not compatible with the type set.
5. Value measured by the humidistat sensor(s)
higher than the corresponding RH set point.
6. Low conductivity water.
1. Close ON/OFF contacts.
2. Check the external connection.
3. Replace the humidistat.
4. Confirm for correct signal type for connected humidistat
using
Selecting the signal type
procedure on Page 17.
5. Using RH meter, confirm accuracy of RH sensor(s).
6. If 220−240 VAC humidifier, consider installing the Low
Conductivity cylinder (Y3484) listed on Page 23.
The humidifier fills with water
without producing steam
1. High steam back pressure.
2. Fill valve strainer clogged.
3. Mineral buildup in the fill cup.
1. Check that the steam hose is not kinked or sagging,
trapping condensate.
2. Clean the fill valve strainer.
3. Clean the fill cup.
The humidifier wets the duct
1. The steam nozzle is not installed correctly (too
near the top of the duct or the condensate return
is blocked).
2. Air flow rate is too low.
3. Humidifier active when the fan in the duct is off.
1. Check that the steam nozzle is installed correctly.
2. Increase air flow in duct or decrease maximum steam
production setting (see Page 17).
3. Check the connection of the device (flow switch or
differential pressure switch) controlling the humidifier to the
ventilation in the duct.
The humidifier wets the floor below 1. The humidifier drain is blocked.
2. The supply water or overflow circuit has leaks.
3. The condensate drain pipe does not bring the
water back to the drain pan.
4. The steam hose is not properly fastened to the
cylinder.
1. Clean the drain assembly and pan.
2. Check the entire water circuit.
3. Check the correct position of the condensate drain hose in
the drain pan.
4. Check the fastening of the hose clamps on the steam
outlet.
Water in the cylinder turns black
1. Minerals in the cylinder have over concentrated
and are deteriorating the electrodes.
1. Check for sags & kinks that could trap condensate in the
steam hoses that could cause a back pressure on the
cylinder.
2. Check the duct static pressure.
3. Check the fill valve and inlet strainer.
4. Check the drain pump operation.
5. Correct installation problems and replace cylinder.
Heavy arcing occurs within hours
of startup
1. The feed water contains large amounts of Iron,
Copper or other conductive contaminants.
1. If you are using a softener, discontinue use.
2. Check the electrodes in the cylinder to be sure they were
not damaged in shipping. Use a ohm−meter to check
whether they are short−circuited. Look through the steam
outlet to see whether the electrodes are loose.
Humidifier continuously fills and
drains without producing steam
1. Mineral has bridged between the electrodes.
2. There is back pressure from the steam hoses or
duct.
3. The flow regulator in the fill valve is broken or
out of place.
4. Water conductivity is very high.
5. Water is foaming excessively.
1. Perform cleaning cycles or replace the cylinder.
2. Check the steam hoses for kinks or gullies that might be
trapping condensate.
3. Replace the fill valve (stuck open).
4. Consider using a mix of demineralized water with raw
water.
5. Check cylinder − replace if exhausted.
