System for refrigerant charge verification

1. A charge-verification tool for use with a charge-verification system to diagnose and remedy a charge condition, the charge-verification tool comprising:

a device having a controller configured to communicate with a system controller in the charge-verification system and a display configured to display measurements and instructions to an installer,

wherein the device is a user interface and is configured to provide communication between the installer and the system controller in the charge-verification system,

the controller prompts the installer to input charge-verification system information including refrigeration line length and diameter,

the controller receives a subcooling temperature determined by the system controller and determines whether the subcooling temperature is between a threshold and a target subcooling temperature, the subcooling temperature being determined based on a liquid line temperature and one of a first coil temperature and a second coil temperature, wherein the system controller determines the one of the first coil temperature and the second coil temperature based on which of the first coil temperature and the second coil temperature is closer to an actual saturated condensing temperature, and

the controller displays an amount of charge to add to the charge-verification system based on whether the subcooling temperature is between the threshold and the target subcooling temperature.

2. The charge-verification tool of claim 1 , wherein the controller displays a system stabilization indication received from the system controller when the charge-verification system stabilizes after startup and after the installer adds charge to the charge-verification system.

3. The charge-verification tool of claim 1 , wherein the controller displays the subcooling temperature and the target subcooling temperature on the display.

4. The charge-verification tool of claim 1 , wherein the controller displays a “done” indication if the subcooling temperature is equal to the target subcooling temperature.

5. The charge-verification tool of claim 1 , wherein if the subcooling temperature is between the threshold and the target subcooling temperature, an undercharge condition exists.

6. The charge-verification tool of claim 1 , wherein if the subcooling temperature is greater than the target subcooling temperature, an overcharge condition exists.

7. The charge-verification tool of claim 6 , wherein if the overcharge condition exists, the controller displays a negative amount of charge to add to the charge-verification system, indicating that charge should be removed from the system.

8. The charge-verification tool of claim 1 , wherein the threshold is two degrees Fahrenheit.

9. The charge-verification tool of claim 1 , wherein the target subcooling temperature is ten degrees.

10. The charge-verification tool of claim 1 , wherein the liquid line temperature is a temperature of liquid in the refrigeration line downstream of an outlet of a condenser.

11. A method of charge verification for use with a charge-verification system to diagnose and remedy a charge condition, the method comprising:

prompting, by a device controller, an installer to input charge-verification system information including refrigeration line length and diameter;

receiving, by the device controller, a subcooling temperature determined by a system controller for the charge-verification system, the subcooling temperature being determined based on a liquid line temperature and one of a first coil temperature and a second coil temperature, wherein the system controller determines the one of the first coil temperature and the second coil temperature based on which of the first coil temperature and the second coil temperature is closer to an actual saturated condensing temperature;

determining, by the device controller, whether the subcooling temperature is between a threshold and a target subcooling temperature; and

displaying, by the device controller, an amount of charge to add to the charge-verification system based on whether the subcooling temperature is between the threshold and the target subcooling temperature.

12. The method of claim 11 , further comprising displaying, by the device controller, a system stabilization indication received from the system controller when the charge-verification system stabilizes after startup and after the installer adds charge to the charge-verification system.

13. The method of claim 11 , further comprising displaying, by the device controller, the subcooling temperature and the target subcooling temperature on the display.

14. The method of claim 11 , further comprising displaying, by the device controller, a “done” indication if the subcooling temperature is equal to the target subcooling temperature.

15. The method of claim 11 , wherein if the subcooling temperature is between the threshold and the target subcooling temperature, an undercharge condition exists.

16. The method of claim 11 , wherein if the subcooling temperature is greater than the target subcooling temperature, an overcharge condition exists.

17. The method of claim 16 , further comprising displaying, by the device controller, a negative amount of charge to add to the charge-verification system, indicating that charge should be removed from the system, if the overcharge condition exists.

18. The method of claim 11 , wherein the threshold is two degrees Fahrenheit and the target subcooling temperature is ten degrees.

19. The method of claim 11 , further comprising prompting the installer to add the charge in two increments if the amount of charge to be added to the charge-verification system is greater than a predetermined threshold.

20. The method of claim 11 , wherein the liquid line temperature is a temperature of liquid in the refrigeration line downstream of an outlet of a condenser.