Aprilaire 1700 Safety And Installation Instructions Manual page 15

TROUBLESHOOTING GUIDE
SYMPTOM
The ventilation damper
does not open when the
HVAC fan is active.
The fan turns on unexpectedly.
The dehumidifier does not run.
The compressor never runs.
(CONTINUED)
TROUBLESHOOTING PROCEDURE / POSSIBLE REASON
• The damper will not open if the cycle time within the current period has already
been met. For instance if the cycle time is set to 5 minutes and the control has
already ventilated for 5 minutes in that interval, the damper will remain closed.
• If using the Outdoor Temperature Sensor, check
that it is installed in the Outdoor Air Intake a
maximum of 3 feet from the outside, or on the
North, East or West side of the house.
(Not in direct sunlight.)
• If the outdoor temperature is below 0°F or above
100°F, the damper will remain closed.
• Verify that the Outdoor Temperature Sensor
is reporting an accurate resistance. Remove the
Outdoor Temperature Sensor leads from ODT
Sensor terminals and check the resistance.
Compare the reading with the resistance shown
in Table 2.
• The control will turn on the fan as needed to meet the air cycling requirements
determined by the cycle time and cycle period settings.
• Follow all of the system checkout procedures.
• Check that the power switch on the dehumidifier is on.
• Check that the circuit breaker is not tripped. The dehumidifier requires a
minimum of 8 amps. The dehumidifier should be placed on its own dedicated
15 amp circuit.
• If a float switch is not installed, confirm that the jumper is installed at the
float switch terminals on the control board.
• If a float switch is installed, confirm that the float switch is not open.
TABLE 2
Outdoor
Temperature
Resistance
-30˚F 229,500 OHMS
-20˚F 162,500 OHMS
-10˚F 116,500 OHMS
0˚F 84,500 OHMS
10˚F
62,000 OHMS
20˚F 46,000 OHMS
30˚F 34,500 OHMS
40˚F 26,000 OHMS
50˚F 20,000 OHMS
60˚F
15,500 OHMS
70˚F 12,000 OHMS
80˚F 9,500 OHMS
90˚F 7,500 OHMS
100˚F 6,000 OHMS
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