Laboratory equipment with flammable refrigerant

A method for operating an item of laboratory equipment with flammable refrigerant, wherein the laboratory equipment comprises:

• an electrical connection for supplying the laboratory equipment with electrical energy, wherein the laboratory equipment is connectable for its operation via the connection to at least two different electrical potentials of an electrical mains supply,
• an electrical switch arrangement having a first electrical switch for electrical separation from a first of the at least two different electrical potentials and having a second electrical switch for electrical separation from a second of the at least two different electrical potentials,
• a sequence controller configured to switch on the first electrical switch and the second electrical switch,
• a monitoring device for monitoring the electrical switch arrangement, wherein the monitoring device is connected via a first contact on the equipment side to the first electrical switch and via a second contact on the mains side to an electrical potential other than the first electrical potential,
• wherein the monitoring device is configured to determine a switched-on state of the first electrical switch when an electrical operating voltage is present between the first contact and the second contact and to signal this state to the sequence controller,
• and wherein the sequence controller,
• when the first electrical switch is expected to be switched off, but it is signaled by the monitoring device that the first electrical switch is switched on, or
• when the first electrical switch is expected to be switched on, but it is signaled by the monitoring device that the first electrical switch is switched off,
• blocks operation of the laboratory equipment.

A method for producing an item of laboratory equipment with flammable refrigerant, wherein the following are provided:

• an electrical connection for supplying the laboratory equipment with electrical energy, wherein the laboratory equipment is connectable for its operation via the connection to at least two different electrical potentials of an electrical mains supply,
• an electrical switch arrangement having a first electrical switch for electrical separation from a first of the at least two different electrical potentials and having a second electrical switch for electrical separation from a second of the at least two different electrical potentials,
• a sequence controller configured to switch on the first electrical switch and the second electrical switch,
• a monitoring device for monitoring the electrical switch arrangement, wherein the monitoring device is connected via a first contact on the equipment side to the first electrical switch and via a second contact on the mains side to an electrical potential other than the first electrical potential,
• wherein the monitoring device is configured to determine a switched-on state of the first electrical switch when an electrical operating voltage is present between the first contact and the second contact and to signal this state to the sequence controller,
• wherein the sequence controller is configured such that,
• when the first electrical switch is expected to be switched off, but it is signaled by the monitoring device that the first electrical switch is switched on, or
• when the first electrical switch is expected to be switched on, but it is signaled by the monitoring device that the first electrical switch is switched off,
• it blocks operation of the laboratory equipment.