Trane ZN.520 Troubleshooting, Test sequence for face-and-bypass unit configurations, Face-and

Troubleshooting

.

Table 27: Test sequence for face-and-bypass unit configurations

DX, or cool or heat/

Face-and-

Electric heat,

Outdoor air

Generic/

Step

Fan

baseboard

cool changeover valve

bypass damper

or heat valve

damper

heat

J1-1

J1-2

J1-3

J1-5

J1-6

J1-7

J1-8

J1-9

J1-10

J1-11

J1-12

TB4-1

1: Off1

Off

Off

Off

Off

NA

Off

On

Off

NA

Off

On

Off

2: Fan high2

High

Off

Off

Off

NA

On

Off

Off

NA

Off

Off

Off

3: Fan med3

Off

Med

Off

Off

NA

On

Off

Off

NA

Off

Off

Off

4: Fan low4

Off

Off

Low

Off

NA

On

Off

Off

NA

Off

Off

Off

5: Main open,

High

Off

Off

On

NA

On

Off

Off

NA

Off

Off

Off

DX on

6: Main close,

DX off, aux

High

Off

Off

Off

NA

On

Off

On

NA

Off

Off

Off

open

7: Aux open,

High

Exh

Off

Off

NA

On

Off

On

NA

Off

Off

Off

exhaust fan5

8: Aux close,

High

Off

Off

Off

NA

Off

On

Off

NA

On

Off

Off

damper open

9: Outdoor air

High

Off

Off

Off

NA

Off

On

Off

NA

Off

On

Off

damper close

10: Generic /

baseboard heat

High

Off

Off

Off

NA

Off

On

Off

NA

Off

Off

On

energized

11: Exit6

Exit

1.Upon entering manual output test mode, the controller turns off all fan outputs and drives all dampers and valves closed (if required).

2.At the beginning of step 2, the controller attempts to clear all diagnostics.

3.If the unit is configured for a 2-speed fan, the fan remains on high speed at step 3.

4.If the unit is configured for a 2-speed fan, the low fan speed output energizes at step 3. If the unit is configured for a 1-speed fan, the fan remains on high speed at step 3.

5.If the unit is configured for a 1- or 2-speed fan, the exhaust fan output energizes on step 7. The exhaust fan output is shared with medium fan speed.

6.After step 10, the test sequence performs an exit. This initiates a reset and attempts to return the controller to normal operation.

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