Table 15 — Durablade Economizer Troubleshooting
| PROBLEM | CAUSE |
| REMEDY |
Damper does not | Indoor fan is off. | 1. | Check to ensure that 24 vac is present at terminal C1 on the IFC or that 24 vac is | |
open. |
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| present at the IFO terminal. Check whether 24 vac is present at |
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| and/or |
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| diagram). |
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| 2. | Check proper thermostat connection to G on the connection board. |
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| No power to economizer | 1. | Check that SW3 is properly making contact with the damper blade. Check that |
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| motor. |
| SW1 is in the NC (normally closed) position. |
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| 2. | Check diode D18. If diode is not functioning properly, replace economizer control board. |
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| 3. | Confirm that the economizer control board is grounded properly at |
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| wire) and at brown terminal of the economizer control board (brown wire). The |
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| economizer motor must also be grounded properly at the negative motor terminal |
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| (brown wire). |
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| 4. | Verify SW1 and SW3 are working and wired properly (see unit label diagram). |
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| 5. | Check for 24 vac input at both |
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| not present, check unit wiring (see unit label diagram). If 24 vac is found in both |
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| places, check for 24 vac at the yellow terminal of the economizer control board |
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| (yellow wire). If 24 vac power is not present, replace the economizer control board. |
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| Economizer motor failure. | If the indoor fan and economizer motor are energized, verify that there is a minimum | |
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| of 18 vdc at the positive motor terminal. If the motor is not operating, replace the | |
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| motor. | |
Economizer operation | OAT or EC set too high. | 1. | Set at correct temperature (3 F below indoor space temperature). | |
limited to minimum |
| 2. | Check OAT or EC by setting above outdoor temperature or humidity level. If the | |
position. |
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| OAT or EC switches do not close, replace OAT or EC. | |
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| Economizer control board | 1. | Perform the following tests when OAT or EC is closed. Y1 is called for, and damper |
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| incorrectly wired or not |
| is at minimum position. Confirm 24 vac on gray terminal of the economizer control |
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| functioning. |
| board (gray wire). If 24 vac is not present, check wiring (see unit label diagram). |
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| 2. | Verify that SW1 and SW3 are wired correctly and working properly (see unit label |
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| diagram). |
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| 3. | Check to ensure that 24 vac exists at |
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| check wiring (see unit wiring label diagram). |
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| 4. | Check 24 vac output at |
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| economizer control board. |
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| Incorrect SAT wiring or | 1. | After verifying that the OAT and EC settings and the economizer control board wir- |
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| inoperative SAT. |
| ing are correct, check to ensure that the 24 vac terminal of the SAT has 24 vac |
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| (white wire). If OAT, EC, and control board are functioning and wired properly and |
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| no 24 vac exists, check wiring (see unit label diagram). |
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| 2. | If |
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| T2 on the SAT (pink wire). If 24 vac is not present, replace SAT. |
Damper does not | Incorrect economizer | 1. | Verify that SW2 and SW4 are wired and working properly (see unit label diagram). | |
close. |
| wiring. | 2. | Check diode D19. If diode is not functioning properly, replace economizer control board. |
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| Incorrect damper actuator | 1. | After verifying that the wiring is correct, modulate the damper to the minimum posi- |
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| wiring or inoperative |
| tion. Remove the calls for G. |
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| economizer circuit board. | 2. | If the damper does not move, check for 24 vac at |
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| present, check wiring (see unit label diagram). |
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| 3. | If damper still does not move, check for 24 vac at blue terminal of economizer con- |
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| trol board (blue wire). If 24 vac is not present, replace the economizer control board. |
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| Incorrect SAT wiring or | 1. | After verifying that the wiring is correct and the economizer control board is func- |
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| inoperative SAT. |
| tioning properly, place the OAT or EC switch in the closed position. Place a call for |
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| Y1 and open the damper to the fully open position. Confirm that the 24 vac terminal |
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| of the SAT has 24 vac (white wire). If 24 vac is not present, check wiring (see unit |
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| label diagram). |
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| 2. | If |
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| on the SAT (violet wire). If 24 vac not found, replace SAT. |
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| Economizer motor failure. | If economizer control board and SAT are functioning properly, verify that there is a | |
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| minimum of 18 vdc at the positive motor terminal. If a minimum of 18 vdc is present | |
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| and the motor is still not operating, replace the motor. | |
Economizer damper | Insufficient battery power, | 1. | Check voltage potential across batteries. If lower than 14 vdc, replace | |
does not close on | inoperative economizer |
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power loss. | control board. |
| ply on a regular basis or whenever the filters are changed. | |
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| 2. | If the |
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| check for 14 vdc or higher at the blue terminal of the economizer control board |
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| (blue wire) when power is disconnected from unit. If 14 vdc is not present, replace |
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| the control board. |
| LEGEND |
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C1 | — Common Power |
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EC | — Enthalpy Control |
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IFC | — Indoor Fan Contactor |
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IFO | — Indoor Fan On |
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OAT | — |
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PL | — Plug |
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SAT | — |
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SW | — Economizer Position Switch |
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