Apparatus and method for cleaning HVAC cooling coils

1. A method of cleaning an HVAC coil unit located above a drain basin, said method comprising steps of:

providing a supply and collection assembly having a reservoir containing liquid cleaning solution, a pump operative to output the liquid cleaning solution through a supply outlet, and a vacuum source operative to draw in used liquid cleaning solution through a collection inlet;

providing a nozzle device in fluid communication with the supply outlet, said nozzle device having a delivery face;

providing a fluid return tool in fluid communication with the collection inlet, and positioning the fluid return tool in the drain basin; and

moving the delivery face of the nozzle device across a surface of the HVAC coil unit to deliver the cleaning solution into areas between fins thereof in a volume of at least 40 gallons per minute.

2. A method as set forth in claim 1 , further comprising connecting a filter assembly between the fluid return tool and the collection inlet in the fluid return path.

3. A method as set forth in claim 2 , wherein the step of moving the delivery face of the nozzle device comprises moving the delivery face across successive horizontal courses of the surface of the HVAC coil unit.

4. A method as set forth in claim 3 , wherein the successive horizontal courses are from top to bottom of the surface of the HVAC coil unit.

5. A method as set forth in claim 2 , wherein said filter assembly comprises a hydrocyclonic filter.

6. A method as set forth in claim 5 , further comprising:

providing an electrically-controlled flush valve in fluid communication with a collection container of said hydrocyclonic filter; and

operating circuitry to open and close the flush valve so as to empty the collection container.

7. A method as set forth in claim 1 , further comprising introducing compressed air into the cleaning solution being delivered from the supply outlet.

8. A method as set forth in claim 7 , further comprising pulsating introduction of the compressed air into the cleaning solution at a predetermined frequency.

9. A method as set forth in claim 8 , wherein said predetermined frequency is less than approximately 36 Hz.

10. A method as set forth in claim 1 , further comprising operating upper and lower level switches within the reservoir and cutting off power to the pump if a threshold upper level of the cleaning solution is reached.

11. A method as set forth in claim 1 , further comprising operating upper and lower level switches within the reservoir and opening a fresh water supply port if a threshold lower level of the cleaning solution is reached.

12. A method as set forth in claim 1 , wherein said nozzle device comprises a delivery face having a substantially planar surface for juxtaposition on the surface of the HVAC coil unit, a plurality of apertures being defined in said delivery face for passage of the cleaning solution.

13. A method as set forth in claim 12 , wherein said apertures are oriented at a predetermined angle relative to the substantially planar surface of the delivery face.

14. A method as set forth in claim 13 , wherein said predetermined angle falls within a range of approximately 45 degrees to approximately 53 degrees.

15. A method of cleaning an HVAC coil unit located above a drain basin, said method comprising steps of:

providing a supply and collection assembly having a reservoir containing liquid cleaning solution, a pump operative to output the liquid cleaning solution through a supply outlet, and a vacuum source operative to draw in used liquid cleaning solution through a collection inlet;

providing a nozzle device in fluid communication with the supply outlet, said nozzle device having a delivery face;

providing a fluid return tool in fluid communication with the collection inlet, and positioning the fluid return tool to collect the used liquid cleaning solution;

sealing the HVAC coil unit to create a first channel; and

moving the delivery face of the nozzle device across a first surface of the HVAC coil unit adjacent the first channel to deliver the cleaning solution into areas between fins thereof.

16. A method as set forth in claim 15 , further comprising:

sealing the HVAC coil unit to create a second channel different from said first channel; and

moving the delivery face of the nozzle device across the first surface of the HVAC coil unit adjacent the second channel to deliver the cleaning solution into areas between fins thereof.

17. A method as set forth in claim 16 , further comprising:

repeatedly sealing the HVAC coil unit to create one or more subsequent channels and moving the delivery face of the nozzle device across the first surface of the HVAC coil unit adjacent the one or more subsequent channels to deliver the cleaning solution into areas between fins thereof until the cleaning solution has been delivered into at least a majority of the first surface of the HVAC coil unit.

18. A method as set forth in claim 15 , wherein sealing the HVAC coil unit to create the first channel comprises sealing portions on two sides of the HVAC coil unit.

19. A method as set forth in claim 15 , further comprising applying suction to a second surface of the HVAC coil unit adjacent the first channel to remove at least one of the cleaning solution and contamination from areas between fins thereof, wherein the second surface is opposite the first surface.

20. A method as set forth in claim 19 , wherein the delivery face of the nozzle device is moved across the first channel, and wherein the suction is applied to an opposite side of the first channel.