DriSteem XT-10 - Page 64

Page 62 • DRI-STEEM XT Series Electrode Steam Humidifier Installation, Operation, and Maintenance Manual
Troubleshooting (continued)
Table 62-1:
Problem/possible cause/action
Problem Possible cause Action
No readable information
on display
No power or incorrect
voltage to processor board
• Check main power supply.
• Reset control transformer circuit breaker if tripped.
Modular communication
cable is disconnected.
• Connect modular cable.
Humidifier does not
energize; steam cylinder
does not heat up
Non-existent supply voltage
to humidifier
• Check main line fuse.
• Check main line safety switch.
• Verify terminal block electrical connections.
• Verify contactor electrical connections.
Non-existent control voltage • Check for proper supply voltage per wiring diagram.
• Verify proper wiring of multi-tap transformer.
• Verify terminal block electrical connections.
• Check for control circuit voltage, 24 VAC. If voltage is not present, check transformer circuit breaker.
• Reset if needed by pressing On/Off switch on display panel.
• Check door interlock switch continuity.
H-H terminals are open. • Check if auxiliary limit controls are not allowing system to operate, e.g., high limit humidistat, airflow
proving switch, etc. Reset, replace, or calibrate as needed. Jumper H-H if auxiliary limit controls are
not used.
Transmitter or humidistat
faults:
• Open, shorted, or incorrect
wiring of transmitter or
humidistat
• Signal is incorrect, out of
range, or miswired.
• Ground loop
• Control signal exceeded
the range limits. Correct
signals are 4 to 20 mA, 0
to 135 ohms, or 0 to 10
VDC.
• Check DC supply voltage terminals of RH transmitter, VAV humidity transmitter, or humidistat:
– Terminal 13: 21 VDC; Terminal 23: GND
• If there is no output 4 to 20 mA, replace transmitter. Transmitter by others may not be compatible.
Consult DRI-STEEM.
• Isolation control board by others may not be compatible. Consult DRI-STEEM.
• Recalibrate if there is a calibration error: Normal range 4 to 20 mA = 0 to 100% RH;
12 mA = 50% RH
• Measure for normal 0 to 10 VDC or 4 to 20 mA control signal.
Reduced or no output
(even though water
level is correct)
Malfunctioning control
system
• Check if auxiliary limit controls are not allowing system to operate, e.g., high limit humidistat, airflow
proving switch, etc. Reset, replace, or calibrate as needed. Jumper H-H if auxiliary limit controls are
not used.
• Check fuse in power circuit. If open, replace fuse with equal fuse.
Steam cylinder
malfunctioning
• Verify that proper voltage is being applied to the steam cylinder.
• Check current through electrode wires.
• If power components are not functioning, replace.
Steam cylinder failure Improper wiring • Verify proper voltage applied to steam cylinder.
• Verify proper electrical connections.
Mineral buildup on steam
cylinder electrodes
• Inspect steam cylinder for severe mineral buildup on or around electrodes. If present, increase
cleaning frequency or replace steam cylinder.
Steam cylinder electrode
corrosion
• Inspect electrodes for surface corrosion or pitting. This is usually caused by a high chloride level in the
supply water. Test water and consult DRI-STEEM for advice.
More on the next page
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XT_IOM_Jan_2008.pdf 64 11/19/2009 10:13:40 AM