If a TEV sensor bulb becomes detached from the suction line, what symptoms will it cause?

When a thermal expansion valve (TEV) sensor bulb becomes detached from the suction line, it leads to improper sensing of the refrigerant temperature and pressure in the evaporator. This disconnection causes the valve to misinterpret the cooling conditions of the system.

The correct answer indicates that there will be high suction pressure and low discharge pressure. This occurs because, without the sensor bulb's proper feedback, the TEV may not respond adequately to the refrigerant needs in the evaporator. As a result, the expansion valve can either remain too open or fail to close properly. The outcome of this is that the evaporator can become flooded with refrigerant, leading to a high suction pressure due to the excess refrigerant that is not vaporizing completely within the coil.

Simultaneously, because the system is not operating efficiently, the compressor may not be able to effectively compress the excess vapor it is receiving from the flooded evaporator, leading to a drop in the discharge pressure. Therefore, the system exhibits high suction pressure and low discharge pressure conditions as a direct result of the sensor bulb's detachment.

Understanding these symptoms is crucial for diagnosing issues in cooling systems and ensuring proper upkeep and functionality in HVAC applications.