Checkout And Troubleshooting - Honeywell C7046C Product Data

SOLID STATE ECONOMIZER SYSTEM
a. On the standard economizers, the damper motor
is energized if the outside air temperature is
below the enthalpy setpoint, thereby opening the
damper and introducing outside air to cool the
conditioned space.
b. On differential economizers, the damper motor is
energized if the outside air temperature is below
the return air temperature, thereby introducing
outside air to cool the conditioned space.
If the logic module uses the outside air for cooling, the
mixed air sensor prevents the entering air from going
below 55°F (13°C).
a. On the modulating system, the control closes the
outside air damper and opens the return air
damper to mix the outside air and return air to
maintain 55°F (13°C).
b. On the three-position system, the mixed air
sensor switch opens, closing the fresh air damper
until the mixed air sensor temperature returns
above 55°F (13°C), closing the switch and
opening the outside air damper.
Standard Economizer Damper Position
Outside
1
Temperature Modulating
80 Closed
75 Closed
70 Open
65 Open
60 Open
55 Open
54 and down Modulating
1
Standard economizer position based on enthalpy control set on the A setting and 50% relative humidity.
2
Closed position is either the minimum position or fully closed, depending on the job setting.
3
Opening/closing is dependent on the mixed air temperature.
Table 5. W7459D maximum outdoor enthalpy switching.
Free Cooling Mode Switching
Into Free Cooling
Outdoor (LED ON) on
RH Decreasing Outdoor
(Percent) Enthalpy
25 83° ±0.5°F
50 78° ±0.5°F
60 76° ±0.5°F
75 73° ±0.5°F
63-2484—1
Table 4. Outdoor air damper positions.
2 2
3-Position
Closed
Closed
Open
Open
Open
Open
Opening/Closing
Out of Free Cooling
(LED OFF)
onIncreasing
Outdoor Enthalpy
85° ±0.5°F
80° ±0.5°F
78° ±0.5°F
75° ±0.5°F
16
a. If the logic module senses that the outside air is
not suitable for cooling, the air conditioning unit
compressor is energized and the space is cooled
with refrigerated air.
b. On the two-stage thermostat, the economizer is
the first stage if the outside air temperature is
suitable for cooling. The compressor on the unit
is energized if the second stage of the
thermostat is energized, thereby creating an
integrated economizer.
Refer to Table 4 for further information on outside air
damper positions.
The W7459D has a high enthalpy limit and defaults to
mechanical cooling when the outdoor enthalpy reaches
the preset limit. Do not use a dry-bulb sensor for a high
temperature limit. Refer to Table 5 for further
information on outdoor air damper positions.
Differential Enthalpy Damper Position
Return
1
Temperature Modulating
80 Closed
85 Open
75 Closed
80 Open
75 Open
75 Open
75 Open
75 Modulating

CHECKOUT AND TROUBLESHOOTING

Tables 6 through 9 provide step-by-step economizer
checkout and troubleshooting steps. See Fig. 19 and 20 for
enthalpy setpoint potentiometer, minimum position
potentiometer and LED and meter locations.
2,3 2,3
3-Position
Closed
Open
Closed
Open
Open
Open
Open
Opening/Closing