Rapid 2005 Installation, Operation & Service Manual page 109

17.8.3 MUA / Exhaust Failsafe Interlock
This option incorporates the low temperature limit
with override timer and an exhaust fan airflow switch
monitor. The exhaust fan airflow switch is field
provided and field wired as per the option sheet
supplied with the unit. When the air handler is turned
on there is a 5 minute establishing period for the low
temperature limit switch and the exhaust fan
interlock. If the air handler's discharge temperature
falls to the predetermined low temperature limit
LOW PRESSURE
SWITCH 0.3 in. w.c.
1
25A
CR4
25
2 3A
CR4
-AFS-3: FIELD LOCATE ON EXHAUST FAN, SWITCH PROVIDIED BY OTHERS
-LOW TEMP LIMIT LOCATED AT DISCHARGE SIDE OF BLOWER
-TO TEST: SET DIAL TO MIN TEMP UNIT OPERATES
SET DIAL TO MAX TEMP UNIT SHUTS DOWN
NOTE: -LOW PRES. SWITCH (BETWEEN WIRES 1 AND 20) REPLACES
LOW PRES. SWITCH (BETWEEN WIRES 8 AND 8A)
-CR3 RELAY NORMALLY OPEN CONTACTS REPLACE LOW PRESSURE SWITCH
ON MAIN WIRING DIAGRAM (BETWEEN WIRES 8 AND 8A)
xxxxxxxxxxx
FIELD WIRED BY OTHERS
CLOGGED FILTER WIRING FOR SDC (80010) AND DTC (80000)
REMOTE PANELS
Part Number Description
01004 MUA/Exhaust Failsafe Inlock
20
CR3
CR3
21
AFS-3
xxxx xx
TD5
3C
3D
TD5
LOW TEMP
LIMIT
TAS-3
3B
RED YELLOW
TD6
TD6
Models
All Models
setpoint, after the 5 minute establishing period, the
air handler fan will be turned off. If there is a failure of
the exhaust fan to activate the field supplied airflow
switch, after the 5 minute establishing period, the air
handler fan will be turned off. To reset the
MUA/exhaust failsafe interlock, set the fan switch to
off and then on again. The air handler will return to
the normal sequence of operations.
AIR FLOW SWITCH
CONTROL RELAY
EXHAUST FAN
AIR FLOW SWITCH
2
TIMING RELAY
SET AT 5 MIN
CR3
8 8A
REPLACES LOW PRESSURE
SWITCH ON MAIN WIRING
DIAGRAM
TIMING RELAY
SET AT 5 MIN
SECTION 17: E
LECTRICAL
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