Nortec MH Series - Manual (Page 78)

75 | Troubleshooting
Code Display
Message
LED System Detected Cause Corrective Action(s)
W20A
Safety Loop
Open
Red
and
Green
Flash
Safety Loop
Open
1 Humidistat open 3 No call for humidity
(normal operation)
2 Air flow blocked 2 Check fan/filter of the
air hancler.
3 Air proving interlock
open
3 If applicable check /
turn on fan.
W21A
Level Sensor
Red
Flash
Defective
controller
1 Level sensor blocked 1 Check that level sensor
can move freely.
E21A Red
2 Level sensor broken 2 Check if level sensor is
closed when float is
raised. If not replace
sensor.
W22A
Fill Timeout
Red
Flash
Level sensor not
closing when fill
valve on
1 Water supply blocked /
shut off
1 Check shut off valve,
filter, pipes, etc.
2 Water treatment
system regenerating
2 Install relay to interrupt
MH safety loop while
system regenerates.
E22A Red
3 Low water pressure 3a Check filter
3b Check for leaks in
supply line.
3c Check supply water
pressure
W23A
Drain Timeout
Red
Flash
Float not
opening when
drain valve open
1 Drain valve blocked or
defective.
1 Check / clean / replace
drain valve.
2 Siphon clogged 2 Clean siphon
3 Relay defective 3 Replace control board.
E23A Red
4 Level sensor stuck or
shorted
4 Clean / replace level
sensor.
5 Pressure equalization
line blocked /
disconnected..
5 Install special siphon.
W25A
μS out of
Range
Red
Flash
Conductivity
sensor reading
out of range
1 Conductivity setting
too low
1 Increase the
conductivity setting in
software.
2 Supply water too
conductive
2 Provide better quality
supply water.
E25A Red
3 Defective conductivity
sensor
3 Replace conductivity
sensor.
4 Defective transmitter 4 Replace conductivity
transmitter.