# Cooling Circuit

URL: https://irs.systems/en/docs/irs-icecube-pro/cooling-circuit

## Connecting the cooling circuit

Connect the hoses of the object to be temperature-controlled to the supply and return of the respective cooling circuit.

## Coupling the cooling circuits

If a large amount of water is required, both supply lines and both return lines can be coupled in parallel.

## Filling up the cooling water

Place the container with the cooling medium in an elevated position and connect it to the connection provided for refilling the cooling water.

## Draining the cooling water

Drain the cooling water via one of the two cooling circuits. Connect a hose to the supply of KK1 or KK2 (cooling circuit 1 or 2) and place the hose in a collecting container. Switch on the respective pump to pump the coolant out of the tank.

> **Note**
> When draining completely, do not let the pump run dry. If a water-glycol mixture is used as the cooling medium, it must not be disposed of via the drain. The operator is obliged to find out in advance which measures and legal requirements must be observed in order to dispose of the coolant properly.

## Replacing the pH sensor

![pH sensor in a holder](/docs/assets/irs-icecube-pro/images/ice-ph-sensor.jpg)

- Drain the tank
- Disconnect the plug
- Remove the sensor

### Calibrating the pH sensor

- Select the calibration menu **CAL**; start the calibration with **CAL**
- Set the pH value of the buffer for **ZERO** with the arrow keys
- Immerse the sensor in test container 1 with the buffer solution (e.g., pH 7), moving the sensor gently
- Start the calibration with **CAL**; when `CAL= ACCEPT` is shown on the display and the displayed mV value is stable, accept the value with **CAL**
- Remove the sensor from the buffer solution, rinse it thoroughly with water and then dab it dry
- Set the pH value of the buffer for **SLOPE** with the arrow keys
- Immerse the sensor in test container 2 with the buffer solution (e.g., pH 4), moving the sensor gently
- Start the calibration with **CAL**; when `CAL= ACCEPT` is shown on the display and the displayed mV value is stable, accept the value with **CAL**
- The determined values for zero point and slope are displayed. If the values for **ZERO** and **SLOPE** are both OK, the calibration is saved as successful. If the result of the calibration is outside the tolerance limits, the error message `ERR` appears
- Continue with **CAL** to confirm the result and end the calibration (if necessary, also unsuccessfully)

> **Note**
> Valid calibration values: zero point -60 mV to +60 mV; slope 40 mV/pH to 65 mV/pH