Installation and Maintenance
EHU-600 Series Humidifiers
8
7.
Control Humidistat
The Series EHU-600 is compatible with any humidistat with the follow-
ing characteristics:
NOTE: Use of shielded wire or wiring in conduit is recommended for
control wiring.
a.
4-20 Milliamps, See Fig. 8-2 for wiring instructions. Note: Printed
Circuit Board has 500 ohm impedance for this type input signal.
Some 4-20 inputs may require a floating ground. Change stat
grounding selector on PC Board. See Figure 9-1.
b. 2-10 Volts, See Fig. 8-2 for wiring instructions. Note: Printed Circuit
Board has 500 ohm impedance for this type input signal. The load
resistor may be removed to increase input impedance, consult factory.
c.
0-135 Ohms, See Fig. 8-3 for wiring instructions.
d. On/Off, See Fig. 8-4 for wiring instructions.
e.
Armstrong Humidistat. See Fig. 8-5 for wiring instructions.
d. Connect the dispersion tube to the steam generator using
minimum 1 1/4" nom. (EHU-600) or 1 1/2" (EHU-601/602) size
hard copper tube (customer supplied) and the two short hoses
supplied with the humidifier. See Figures 7-1 and 8-1. Insulate
the copper tube to minimize condensation. Long runs of pipe
and/or high duct static pressure may require 1 1/2" or 2" copper
pipe. See Figure 8-6.
If the optional 10 ft. flexible steam hose is used, cut the steam
hose to length as required. Wipe out the inside of each hose end
before installing. Connect the cut end of the hose to the dispersion
tube. Tighten all hose clamps.
e. If duct static pressure and piping back pressure exceeds 4" W.C.
please consult factory for special mounting procedures.
Steam hose or pipe must be free of loops, kinks, and sags to
allow for gravity drainage of condensate. (Provide pitch of 1"
per foot.) Hose supports may be required to accomplish this.
Figure 8-1: Connection at Unit
Figure 8-2: 4-20 Milliamps Humidistat
2-10 Volts Humidistat
Please consult factory for additional information on wiring
A18609, A18610, or A17888 Armstrong Humidistats.
Figure 8-4: On/Off Humidistat
Figure 8-3: 0-135 Ohms Humidistat
Figure 8-5: Armstrong Humidistat
Lb. / Hr. Steam
Figure 8-6:
Pressure Loss in Copper Pipe
(40 Feet Equivalent Run)
GND
+Input
500 OHM Input
Impedence ON
4-20 mA/2-10V
Stat. Selection
4-20 mA Stat.
OR
2-10 V Stat.
+5VDC
+Input
Brown
Orange
Opens with Increase
in Humidity
ON/OFF Stat.
AMW Part No.
A-8581 or
A-8581-A
0 – 135 OHM
STAT.
AMW PART NO.
A-8821
HUMIDITY
INCREASE
+5VDC
G N D
+INPUT
B L A C K
WHITE
R E D
Common
1.9-3.9 Vdc. Input
12 Vac Power
White
Green
Black
25
Armstrong
26
Solid State
27
Humidistat
AMW Part No.
C-1471 or
C-1472
1-3/8" O.D. (1-1/4" Nom.)
Copper Tube
Insulation
EHU
Cabinet
Top
Hose Clamps
Rubber Hose Cuff
Steam Generator Tank
