Drain pan level monitoring system

1. A drain pan level monitoring system of an air conditioning system, comprising:

a level sensor that generates (1) a first level sensor output signal related to a first positive value rate of condensation buildup within a drain pan and (2) a second level sensor output signal related to a second positive value rate of condensation buildup within the drain pan, wherein the level sensor is configured to generate the first level sensor output signal prior to generating the second level sensor output signal; and

an alert device configured to indicate that there may be a buildup of debris in the drain pan if a value of the second positive value rate is greater than a value of the first positive value rate by a predetermined amount.

2. The drain pan level monitoring system according to claim 1 , wherein the level sensor comprises a pressure transducer.

3. The drain pan level monitoring system according to claim 1 , wherein the level sensor substantially continuously generates a level sensor output signal.

4. The drain pan level monitoring system according to claim 1 , wherein the level sensor intermittently generates a level sensor output signal.

5. The drain pan level monitoring system according to claim 1 , further comprising:

memory for storing a value of the level sensor output signal.

6. The drain pan level monitoring system according to claim 1 , further comprising:

an air handling unit controller in communication with the level sensor and receiving the level sensor output signal.

7. The drain pan level monitoring system according to claim 6 , wherein the air handling unit controller substantially continuously receives the level sensor output signal.

8. The drain pan level monitoring system according to claim 6 , wherein the air handling unit controller intermittently receives the level sensor output signal.

9. The drain pan level monitoring system according to claim 6 , further comprising:

a communicating thermostat in communication with the air handling unit controller.

10. A method of monitoring a liquid level buildup in a drain pan of an air handling unit, comprising:

determining a first positive value rate of liquid buildup in the drain pan;

storing the first positive value rate of liquid buildup to a memory;

operating the air handling unit;

ceasing operation of the air handling unit;

after determining the first positive value rate of liquid buildup in the drain pan, determining a second positive value rate of liquid buildup in the drain pan after the ceasing operation of the air handling unit; and

performing an action if the second positive value rate of liquid buildup is greater than the first positive value rate of liquid build up by more than a predetermined amount.

11. The method according to claim 10 , wherein the action performed is shutting off the air handling unit.

12. The method according to claim 10 , wherein the action performed is activating a condensation pump associated with the drain pan.

13. A method of preventing liquid overflow of a drain pan of an air handling unit, comprising:

monitoring rates of liquid level buildup within the drain pan;

taking an action when at least one of the rates meets a predetermined criteria;

wherein the predetermined criteria comprises determining that a first positive rate value measured is less than a second positive rate value that is measured after the first positive rate value is measured, wherein the air handling unit is operated between the measuring of the first positive rate value and the measuring of the second positive rate value.

14. The method according to claim 13 , wherein the action taken is shutting down the air handling unit, activating an alert device, or both.

15. The method according to claim 13 , further comprising:

retaining a value of at least one of the first positive rate value and the second positive rate value for later reference.