46
Installation
2582302_C_EN_1611
Nortec EL
5.8.3.3 External Safety Chain
The external safety chain consists of potential-free contacts of the external monitoring devices (for ex
-
ample, high limit humidistat, air proving switch, etc.) which are connected in series to terminal points "1"
and "2" on the low voltage terminal strip. Refer to
Figure 24 on page 41
and
Figure 28
.
If the blower pack is installed, then connect it to terminal points "8" and "9" on the low voltage terminal
strip. Make sure that no other wires are connected to these terminal points. If using multiple blower
packs, make sure that they are connected in series.
Note:
Interrupting the external safety chain disconnects power from the contactor and fill valve, and is
intended as a safety precaution. To control the humidifier with an on/off humidistat refer to
"External On/
Off Input" on page 49
for details.
IMPORTANT!
Install a jumper between terminal points "8" and "9" on the low voltage terminal
strip if the blower pack is not used.
IMPORTANT!
A high limit humidistat is highly recommended to prevent over-humidification and
potential damage to property.
IMPORTANT!
Install a jumper between terminal points "1" and "2" on the low voltage terminal
strip if no external On/Off devices are connected to the safety chain – not recommended.
The connecting cables must lead into the control cabinet through a cable gland or grommet.
CAUTION!
Risk of damage to internal components!
Prevention:
DO NOT apply voltage to low voltage terminal strip terminal points "1" and "2"
through the contacts of the external On/Off devices.
Figure 28:
+
max
φ
Δp
External
5
4
3
2
1
LV
8
7
6
5
4
3
2
9
1
External Safety Chain Connections
1 Blower pack
2 High limit humidistat – highly recommended
3 Air proving switch
4 Jumper (installed if no devices connected to safety chain – not recommended)
5 Jumper (installed if the blower pack is not used)