Findings: Liquid level in receiver too high

Cause: Partial blockage of a component in liquid line.

 Action: Find the component and clean or replace it

Cause: Thermostatic expansion valve fault (e.g. superheat too high, orifice too small, lost charge, partial blockage).

 Action: Set thermostatic expansion valve to a lower superheat setting or check if a bigger orifice will bring the superheat down. When changing/removing the orifice, check if dirt etc. blocks the valve (clean it). If the sensor bulb charge is lost, warming up the bulb with your hand will not open the valve. If the charge is still there it will open.

Cause: Insufficient refrigerant in system.

Action: Investigate cause (leakage, overcharge in evaporator), repair fault and charge system if necessary.

Findings: Liquid level in receiver too low

Cause: Evaporator overcharged.

 Action: Thermostatic expansion valve setting/installation not ok, bulb location wrong    

Cause: Thermostatic expansion valve fault (e.g. superheat setting too low, bulb location wrong)

Action: Set thermostatic expansion valve to a higher superheat setting and check expansion valves bulb location (after evaporator, all collector pipes and in front of external pressure equalization)

Cause: Refrigerant collection in condenser because condensing pressure is too low

Action: Air-cooled condensers: Establish condensing pressure regulation by fan motor speed regulation, e.g. type RGE.

Cause: Insufficient refrigerant in system.

Action: Investigate cause (leakage, overcharge in evaporator), repair fault and charge system if necessary.

Cause: Evaporator overcharged.

Action: Thermostatic expansion valve setting/installation not ok, bulb location wrong.

Cause: Refrigerant charge in system too large.

Action: Recover a suitable quantity of refrigerant, but condensing pressure must remain normal and the sight glass free of vapor.

Findings: Temperature in receiver too high

Cause: KVD receiver pressure regulator set for too low a pressure.

Action: Set the receiver pressure regulator at a higher pressure. It might also be necessary to increase the setting of the condensing pressure regulator.

Cause: Bellows in KVD receiver pressure regulator might be leaking.

Action: Slowly loosen protective cap. If pressure or traces of refrigerant exist under the cap, there is a leak in the bellows. Replace valve.