Installation and Maintenance
EHU-600 Series Humidifiers
31
Humidistat
Troubleshooting
If the Armstrong Humidistat is mis-wired Table 31-1 shows the unit
response. * indicates wrong wire connected. W, G, and B stand for
white, green, and black, the wire colors on the humidistat. See Section
7 for more information on control humidistat wiring.
Table 31-1
Terminal
Demand Meter
Functional Response
22
6
7
Responds to stat normally,
Correct wiring. Unit fills
W
G
B
0% with jumper disconnected.
and drains normally.
100% with sensor out.
B*
G
W*
5 demand lights flicker with
Contactor cycles or
B*
W*
G*
or without sensor or pigtail
chatters. Unit fills continuously.
G*
B*
W*
5 demand lights flicker with
Contactor chatters
or without sensor or pigtail.
Unit will not fill.
G*
W*
B*
1 or no demand light(s) flicker
Tank off. Contactor will
W
B*
G*
with or without sensor or pigtail.
not energize. Unit will not fill.
Table 31-2 shows the units response if jumper BJ2 is in the wrong
position and the Armstrong humidistat is wired correctly. See Section 7
for more information on jumper locations and selections.
Table 31-2
Jumper
BJ2 Pin No.
Labeled
Functional Response
4
1.9-3.9
Correct Pin No. Unit
responds normally.
3
2-10V/4-2MA
0% demand. Unit will
not fill. Tank off.
2
0-135 On/Off
Unit responds normally
but over wider %RH range.
