Table 20 Ð Durablade Economizer Troubleshooting
| PROBLEM |
| CAUSE |
| REMEDY |
Damper does not |
| Indoor (evaporator) fan is off. | 1. | Check to ensure that 24 vac is present at terminal C1 on the IFC or that | |
open. |
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| 24 vac is present at the IFO terminal. Check whether 24 vac is present at | |
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| wiring (see unit label 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 | |
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| motor. |
| that SW1 is in the NC (normally closed) position. |
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| 2. | Check diode D18. If diode is not functioning properly, replace D18. |
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| 3. | Con®rm that the economizer control board is grounded properly at |
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| (brown wire) and at brown terminal of the economizer control board |
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| (brown wire). The economizer motor must also be grounded properly at the |
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| negative motor terminal (brown wire). |
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| 4. | Verify SW1 and SW3 are working and wired properly (see unit label |
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| diagram). |
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| 5. | Check for 24 vac input at both |
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| 24 vac not present, check unit wiring (see unit label diagram). If 24 vac is |
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| found in both places, check for 24 vac at the yellow terminal of the econo- |
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| mizer control board (yellow wire). If 24 vac power is not present, replace the |
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| economizer control board. |
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| Economizer motor failure. | If the indoor (evaporator) fan and economizer motor are energized, verify that | |
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| there is a minimum of 18 vdc at the positive motor terminal. If the motor is not | |
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| operating, replace the motor. | |
Economizer op- |
| OAT or EC set too high. | 1. | Set at correct temperature (3 F below indoor space temperature). | |
eration limited to |
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| 2. | Check OAT or EC by setting above outdoor temperature or humidity level. If | |
minimum position. |
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| the OAT or EC switches do not close, replace OAT or EC. | |
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| Verify economizer control | 1. | Perform the following tests when OAT or EC is closed, Y1 is called for and |
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| board is correctly wired and |
| damper is at minimum position. Con®rm 24 vac on gray terminal of the |
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| works properly. |
| economizer control board (gray wire). If 24 vac is not present, check wiring |
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| (see unit label diagram). |
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| 2. | Verify that SW1 and SW3 are wired correctly and working properly (see unit |
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| label diagram). |
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| 3. | Check to ensure that 24 vac exists at |
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| present, 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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| Check SAT. | 1. | After verifying that the OAT and EC settings and the economizer control |
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| board wiring are correct, check to ensure that the 24 vac terminal of the SAT |
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| has 24 vac (white wire). If OAT, EC, and control board are functioning and |
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| wired properly and no 24 vac exists, check wiring (see unit label diagram). |
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| 2. | If |
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| terminal T2 on the SAT (pink wire). If 24 vac is not present, replace SAT. |
Damper does not |
| Incorrect wiring of | 1. | Verify that SW2 and SW4 are wired and working properly (see unit label | |
close. |
| economizer. |
| diagram). | |
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| 2. | Check diode D19. If diode is not functioning properly, replace D19. |
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| Verify economizer control | 1. | After verifying that the wiring is correct, modulate the damper to the mini- |
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| board is functioning properly. |
| mum position. Remove the calls for G. |
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| 2. | If the damper does not move, check for 24 vac at |
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| is not 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 econo- |
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| mizer control board (blue wire). If 24 vac is not present, replace the econo- |
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| mizer circuit board. |
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| Check SAT. | 1. | After verifying that the wiring is correct and the economizer control board is |
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| functioning properly, place the OAT or EC switch in the closed position. |
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| Place a call for Y1 and open the damper to the fully open position. Con®rm |
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| that the 24 vac terminal of the SAT has 24 vac (white wire). If 24 vac is not |
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| present, check wiring (see unit label diagram). |
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| 2. | If |
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| terminal T1 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 | |
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| a minimum of 18 vdc at the positive motor terminal. If a minimum of 18 vdc is | |
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| present and the motor is still not operating, replace the motor. | |
Economizer |
| Verify that | 1. | Check voltage potential across batteries. If lower than 14 vdc, replace close- | |
damper does not |
| loss and economizer control |
| ||
close on power |
| board are functioning |
| you check this emergency power supply on a regular basis or whenever the | |
loss. |
| properly. |
| ®lters are changed. | |
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| 2. | If the |
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| properly, check for 14 vdc or higher at the blue terminal of the economizer |
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| control board (blue wire) when power is disconnected from unit. If 14 vdc is |
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| not present, replace the control board. |
| LEGEND |
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C1 | Ð Common Power |
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EC | Ð Enthalpy Control |
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IFC | Ð Indoor (Evaporator) Fan Contactor |
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IFO | Ð Indoor (Evaporator) Fan On |
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OAT Ð |
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PL | Ð Plug |
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SAT | Ð |
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SW | Ð Economizer Position Switch |
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