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| REPLACEMENT | DEFROST CONTROL BOARD |
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| PRESSURE |
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| SWITCH |
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SAFETY CIRCUIT |
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CONNECTIONS |
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| / | DIAGNOSTIC LEDs | |
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CONNECTION | FOR |
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ONE OPTIONAL | SWITCH |
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| DEFROST | INTERVAL |
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| PS2 |
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| TIMING | PINS |
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| PS1 |
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| 24V TERMINAL | STRIP |
CONNECTIONS | FOR |
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TWO OPTIONAL |
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| CONNECTIONS | ||
SWITCHES |
| SERVICE | LIGHT |
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[] | ps2 | ....... | ONNECT,ON |
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| Psi | ......................... | ......................... |
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| FIGURE 1 |
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Time-Delay
The
Pressure Switch Safety Circuit
The defrost control incorporates a pressure switch safety circuit that allows the application of up to two optional pressure switches; high pressure and/or loss
of charge. See figure 1. During a demand cycle, the defrost control will lock out the unit on the third
instance that the unit goes off on any pressure switch wired to this circuit. The diagnostic LEDs will display a pattern for a lockout pressure switch on the third
open pressure switch occurrence. See table 1. The unit will remain locked out until the switch is reset.
Remove
control board. See figure 1. When only one pressure switch is used, wire the switch to the two outside terminals of the pressure switch connections.
NOTE: If not using a pressure switch, the
factory-installed jumper wire must be connected.
Diagnostic LEDs
The defrost board uses two LEDs for diagnostics. The LEDs flash a specific sequence according to the condition.
TABLE 1
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| DEFROST CONTROL BOARD DIAGNOSTIC LED | |||
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| LED 1 | LED 2 |
Normal | Operation/ | Flash together | Flash together | ||
Power | to board |
| with LED 2 | with LED 1 | |
_me | Delay |
| Alternating | Alternating | |
| Flashes | Flashes | |||
To Protect Compressor | |||||
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| with LED 2 | with LED 1 |
Pressure | Switch | Open | Off | On | |
Pressure | Switch | Lockout | On | Off | |
Board | Malfunction |
| On | On | |
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