Honeywell C7400 Manual page 33

Solid state economizer system
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CHECKOUT AND
TROUBLESHOOTING: W7212
Checkout requires a 9V battery, 620 ohm, 1.2K ohm, 5.6K
ohm, and 6.8K ohm resistors. Use Table 10 and Fig. 38 for
checkout.
CAUTION
Equipment Damage Hazard.
Excessive force can damage potentiometer
controls.
Use a small screwdriver when adjusting enthalpy
changeover and minimum damper position controls.
Table 10. Checkout for W7212, W7213, W7214 Economizers Connected to Honeywell Actuator.
Step
Checkout Procedure
1.
CHECKOUT PREPARATION
Disconnect power at TR and TR1.
Disconnect devices at P and P1.
Jumper P to P1.
Place 5.6K ohm resistor across T and T1.
Jumper TR to 1.
W7212 only: Jumper TR to N.
If connected, remove C7400 Enthalpy Sensor from
terminals S
and +.
O
Connect 1.2K ohm 4074EJM Checkout Resistor across
terminals S
and +.
O
Put 620 ohm resistor across S
Set minimum position, DCV setpoint, and Exhaust
potentiometers fully CCW.
Turn DCV maximum position potentiometer fully CW.
Set enthalpy potentiometer to D.
Apply power (24 Vac) to terminals TR and TR1.
2.
DIFFERENTIAL ENTHALPY
Execute step one, Checkout Preparation.
Place 620 ohm resistor across S
Place 1.2K ohm resistor across S
Remove 620 ohm resistor from S
3.
SINGLE ENTHALPY
Execute step one, Checkout Preparation.
Set enthalpy potentiometer to A (fully CCW).
Set enthalpy potentiometer to D (fully CW).
and +.
R
and +.
O
and +.
R
and +.
O
33
SOLID STATE ECONOMIZER SYSTEM
W7212
1
DC VOLTMETER
+
S
C7400
+
2
620 OHM RESISTOR
1
INSERT DC VOLTMETER BETWEEN AQ AND AQ1 FOR
CHECKOUT AND TROUBLESHOOTING.
2
JUMPER USED FOR SINGLE ENTHALPY CONTROL.
Fig. 38. Meter location for checkout and troubleshooting
(W7212 shown).
Proper Response
All LED are off; Exhaust Fan contacts are open.
Free cool LED turns on.
Free cool LED turns off.
Free cool LED turns on.
Free cool LED turns off.
EXH
N1
Set
N
2V
10V
EXH
P1
P
Min
Pos
T1
Open
T
DCV
Max
2V
10V
AQ1
DCV
AQ
DCV
Set
SO+
2V
10V
SO
Free
SR+
Cool
B
C
SR
A
D
M20612
63-2484—03

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