YORK YK — Condenser - Freeze threat - Flow switch open

The panel reads Condenser - Freeze threat - Flow switch open; the freeze-prevention documentation prints the same message as Condenser - Freeze Threat - Flow Switch Open. The manuals treat it as a cycling fault belonging to the subcooler tube freeze prevention logic, and one of them also calls it a panel warning. It is shown while the chiller is in a stopped state and the condenser flow switch is open. If the display shows a related message instead — Condenser - Flow Switch Open, Warning - Condenser - Freeze threat from low pressure, Condenser - High pressure or Condenser - High Pressure - Stopped — this page does not cover it.

The message is a panel warning of a potential condenser/subcooler tube freeze threat, raised while the chiller is stopped with the condenser flow switch open. One manual places it in the cycling faults list and states the conditions under which the fault is set and released; the other places it in the subcooler tube freeze prevention logic and describes it as a warning that resets automatically. In both versions the message simply reflects the current state of the condenser flow switch and the condenser-side temperatures, and it leaves the panel by itself once those conditions change.

• The cycling faults table states the set condition as follows: the condenser flow switch has remained open for more than 1 min while the chiller is in a stopped state, and the fault is set when the condenser saturation temperature is less than 34.0°F (1.1°C) and the drop leg temperature is less than 35.0°F (1.7°C).
• The freeze-prevention note states the condition with different thresholds: the chiller is stopped, the saturated condenser temperature is less than 35.0°F, and the condenser flow switch has been open for 60 seconds or longer.

1. Confirm the chiller state: both documents apply this message only while the chiller is stopped, so establish whether the machine is running or stopped first.
2. Look at the condenser flow switch input. The control's Digital Inputs Diagnostic screen includes a low-voltage digital input for the condenser liquid thermal-type flow switch, J14-7; this message requires that switch to read open.
3. Read the saturated condenser temperature on the panel and compare it with the set thresholds listed below.
4. Read the drop leg temperature, which the cycling faults table uses both in the set condition and in the release condition.

• Set condition, cycling faults table: chiller stopped, condenser flow switch open for more than 1 min, condenser saturation temperature less than 34.0°F (1.1°C), drop leg temperature less than 35.0°F (1.7°C).
• Set condition, freeze-prevention note: chiller stopped, condenser flow switch open for 60 seconds or longer, saturated condenser temperature less than 35.0°F.
• Release condition, cycling faults table: condenser saturation temperature greater than 36.0°F (2.2°C), or drop leg temperature greater than 36.0°F (2.2°C) held for 5 min consecutively, or the condenser flow switch closed.
• Release condition, freeze-prevention note: chiller running, or saturated condenser temperature greater than 40.0°F, or the condenser flow switch closed.

Neither manual describes a manual reset; both give an automatic release. The fault is released if the condenser flow switch is closed, the condenser saturation temperature is greater than 36.0°F (2.2°C), or the drop leg temperature has been greater than 36.0°F (2.2°C) for 5 min consecutively. The freeze-prevention note adds that the warning will automatically reset whenever the chiller is running, the saturated condenser temperature rises above 40.0°F, or the condenser flow switch closes. In practice the message clears on its own once the switch closes, the chiller runs again, or the condenser-side temperatures recover past the release thresholds.