17
VAPOR-LOGIC
®
VERSION 6 INSTALLATION AND OPERATION MANUAL
Airflow switch in a duct
When using an SDU
Duct high limit (not used on SDU or Area-type)
INSTALLATION
Control circuit wiring
Field wiring
Optional factory
Optional field
Break to external
connections diagram
Key
Vapor-logic
24VAC
Duct air flow
switch (N .O .)
NO
Com
Vapor-logic
P13
P13
24VAC
24VAC
21VDC
DHL
21VDC
DHL
P13
P13
NC contact
opens above
set point
Duct air flow
switch is in
SDU cabinet
Duct air flow switch is not
used on Area-type
Note:
Field wiring required between SDU cabinet terminal
strip for SDU blower and air flow switch
21 VDC
Transmitter
On/off
Vapor-logic
Vapor-logic
4-20 mA
High limit sensor
Duct mount
Modulating high limit
NC
C
GN
2-wire #18GA
shield cable (TYP)
Control panel
shield GND lug
2-wire #18GA
shield cable (TYP)
Control panel
shield GND lug
V
RH
Temperature compensation transmitter or auxiliary temperature sensor
Note: This control is not available for XT humidifiers
Temp comp transmitter
Vapor-logic
Control panel
2-wire #18GA
shield cable (TYP)
P14
21VDC
TS
RD
WH
Step 1 – Field wiring: Limit controls
FIGURE 17-1: VAPOR-LOGIC LIMIT CONTROLS WIRING CONNECTIONS
Note:
An airflow switch must be used in any duct
humidification application . If no airflow switch
is used, install shunt at P13 (24VAC to AFSW) .