C

EW

CONTROLS INC.
Excellence Without Compromise
R

APPLICATION NOTE

AN 147 FAN FAILURE SAFETY LOCK-OUT CIRCUIT “Field Provided”EWC Controls Inc. 385 Highway 33 Englishtown, NJ 07726 800-446-3110 732-446-3110 FAX 732-446-5362
.. . ..
R W G Y
TYPICALTHERMOSTAT
RWGY C
FURNACE
HUMIDISTAT
G1 R G2 HH
S2000 & S2020 HUMIDIFIER
NO
NO NC
C
FAN FAILURE SAFETY LOCK-OUT CIRCUIT
SEPARATE
SAIL SWITCH
OR
CURRENT SENSING
RELAY CONTACTS
SPDT
K1 Interlock
Basic RELAY
24 VAC COIL
The use of a safety lock-out circuit is highly recommended. The circuit below is effective atstopping the humidifier operation if the fan motor fails for any reason. The use of a systeminterlock is optional and not required for basic operation. Failure to incorporate a lock-out can result in excessive condensation inside the duct work and/or possible flood damage, if the HVAC Fan/Blower fails to operate. This solution is provided as a supplement. Flood or water damage as a result of not using this diagram is not the responsibility of EWC Controls.
K1 COIL
K2 COIL
SPST
K2 Interlock
Optional RELAY
24 VAC COIL
NO