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—17—
620 ohm
JUMPER
}
24 VAC SUPPLY FROM
ECONOMIZER CONTROL
SECTION (RED TO TR,
BRN TO TR1)
TO SENSOR MOUNTED
ON BACK OF CONTROL
}
GRAY WIRE FROM
ECONOMIZER HARNESS
RED WIRE FROM
ECONOMIZER SWITCH 3
(NORMALLY CLOSED)
TR
TR1
SO +
+
SR
2
3
1
LED
A
B
C
D
LED
A
B
C
D
TR TR1
SO
SR
2
3
1
+
+
S
+
(HH57AC078
SENSOR)
24 VAC SUPPLY FROM
ECONOMIZER CONTROL
SECTION (RED TO TR,
BRN TO TR1)
TO SENSOR MOUNTED
ON BACK OF CONTROL
GRAY WIRE FROM
ECONOMIZER HARNESS
RED WIRE FROM
ECONOMIZER SWITCH 3
(NORMALLY CLOSED)
1
2
3
BRN
COMPRESSOR
SAFETIES
BRN
CLO
TIME GUARD I I DEVICE
C
OR
CR
T1
T3
T2
TIME GUARD I I DEVICE
C
OR
CR
BRN
T1
T3
T2
HIGH EFFICIENCY 3 TO 12
1
/
2
TON ROOFTOP UNITS
STANDARD EFFICIENCY 3 TO 12
1
/
2
TON ROOFTOP UNITS
LEGEND
Fig. 16 — Time Guard® II Device; 558F036-150
C — Contactor
CLO — Compressor Lockout
CR — Control Relay
NOTE: Switches shown in high enthalpy state. Terminals 2 and 3
close on enthalpy decrease.
Fig. 17 — Wiring Connections for Solid-State
Enthalpy Control (HH57AC077)
NOTES:
1. Remove factory-installed jumper across SR and + before con-
necting wires from HH57AC078 sensor.
2. Switches shown in high outdoor-air enthalpy state. Terminals 2
and 3 close on low outdoor air enthalpy relative to indoor air
enthalpy.
Fig. 18 — Wiring Connections for Differential
Enthalpy Control (HH57AC077 and HH57AC078)