I need to warn you…

The following list is the actual process we use at the company I own for our typical “standard” residential maintenance. I'm sure you will find some things you do differently. Take it for what it is, and I'm happy to get any feedback you may have.

• Read the call notes, property notes, and customer notes. Check the last service call and last notes and readings so that you are aware of the service history.
• Check the filter size and ensure you have the PROPER filter if possible.
• Put on shoe covers before you enter the customer's home. (Note: It's best to do this on the front porch instead of right when you get out of your van. That way, you won't track grass clippings, dirt, or other debris from the sidewalk into the home.)
• Ask the customer if they have noticed anything unusual with the system.
• Inspect and set the thermostat to run. Shine a light in the return to check for filters, blockages, debris, or damage.
• Visually inspect the system operation to make sure all of the components appear operational before beginning the maintenance. Note anything out of the ordinary and bring it to the owner's attention. Address or diagnose those issues before proceeding.
• Remove disconnects/shut off breakers. Check for proper breaker sizes, and inspect disconnect wires, lugs, and pulls.  
• Remove the condenser top and panels. Place them carefully in the grass away from damage.
• Remove any debris from the bottom of the unit. Inspect wires and compressor terminals while doing this. Use a vacuum to remove dirt and leaves as required. If grading is poor, use a shovel to scrape dirt/leaves away from the base of the unit.
• Wash the coil well, starting from inside out and from top to bottom. Only use coil cleaner according to the labeled dilution and only use it when the coil requires it.

• Check the inside of the condenser one final time for any potential wiring or copper rubouts and repair/isolate as required. Note any rust on the compressor, roto locks, or accumulator.
• Inspect the crankcase heater (if the system has one). Confirm the operation by the amperage or ohming out.
• Look for any signs of refrigerant oil, as that may give away potential leak points. 
• Replace the top carefully, ensuring that you don’t pinch any wires. Rewire the fan.
• Inspect all wiring connections in the condenser control box for tightness and damage. Check contactor points and note their condition.
• Move inside. If the air handler has a finished floor around it, lay down a drop cloth. Always keep the work area inside clean during and after work.
• Check the evaporator coil condition and cleanliness top and bottom. If the coil is a slant coil orientation and has any dirt on it, clean the surface with an evaporator coil cleaner, pump sprayer, rag, and a soft brush. If the coil is dirty and an A or another coil type that cannot be easily cleaned in place, you may quote the customer for coil removal and cleaning if it has no known leaks and is less than 7 years old.
• Connect a wet vac to the drain outside.

• Remove the panels from the air handler and begin pouring water into the drain pan, all the while helping any sludge in the pan get removed by moving it toward the pan outlet. Use duct tension straps or zip tie ends/small bottle brushes to help pull sludge out from the sides of the pan under the coil and clean all channels.
• Run a minimum of 2 gallons of water through the pan, and then empty the vacuum. Run another gallon through and repeat the process until the pan is visibly clean and the water in the vacuum is clean.
• Run 1 more gallon through the drain once done and ensure it runs out.
• Spray and wipe down the inside and outside of the air handler, including wires, with a safe anti-microbial solution.
• Remove any dust from the blower motor body and end bell with a vacuum, rag, or soft brush, being careful not to force dust further into the motor. When the dust buildup is severe, use compressed air or nitrogen and a vacuum to remove it.  
• Test the blower capacitor by removing the leads, testing with a capacitor tester, and reconnecting the leads.
• Inspect the blower wheel for cleanliness. If it is dirty, check the particular maintenance type to see if removing and cleaning the blower is extra or included.
• Check the blower motor bearings for play.
• Inspect all wires for rubouts inside and outside the air handler. Inspect the disconnects and check any lugs for tightness.
• Check low voltage wiring and dip switch/pin settings. If the system has an advanced interface, you will need to check for proper settings at the controller.
• Check coil feeder tube location and condition. If tubes begin to rub out, isolate them and strap them together using foam tape and zip ties.
• Inspect the float switch for proper installation and wiring. Test the float switch to ensure it breaks the circuit when the float rises. If there is no float switch, quote to install one at the end of service. 
• Check air handler panel insulation and glue or retape it as required.

• Spray down the coil surface lightly with antimicrobial and add 3 pan tabs to the front of the drain pan away from the outlet. Instead of pan tabs, you could also use Refrigeration Technologies Pan & Drain Treatment.
• Install a new air filter with the date and your name.
• Replace the bottom air handler panels and turn the air handler breaker on.
• Run the heat and test the heat strips on and off using an amp meter; note heater and blower amps.
• Shut off the air handler, replace all panels, and double-check that the drain cleanout cap is in place and the float switch is in the correct position.    
• Put the system into cool mode and turn the air handler back on (condenser disconnect still off/out).
• If the system has been checked during previous calls and has no history of leaks, then use the historical data to perform a non-invasive refrigerant test. If this is the first maintenance or if the system has a history of issues, then connect gauges.
• Connect an amp clamp to compressor common and observe as you turn on the condenser breaker/disconnect.
• Test the L1 & L2 voltage and ensure it is in the acceptable range
• Allow the system to run for at least 10 minutes. During this time, you can begin cleaning up.
• Start filling out the service call/collecting model and serial numbers (if required).
• Inspect suction insulation and thermostat wire outside for damage or poor splices
• Perform the “under load” capacitor test (you can read our article about that test HERE).
• Read across the contactor points to see if there is any voltage drop in the contact points.
• Once the system has run for 10-15 minutes, perform either the non-invasive test protocol (read about non-invasive testing HERE) or check and note suction, head, superheat, subcool, and delta T according to the “5 pillars” tests and any manufacturer guidelines (read about the “5 Pillars” test HERE).

• If the system is a heat pump, test the opposite mode (usually heat) to ensure the reversing valve shifts properly and the system runs.
• Note any suggested repairs or improvements to the customer and get their response.
• Clean up fully and double-check drains, refrigerant caps, and disconnects. Call on standby.
• Wrap up paperwork with the customer.
• Ask the customer if there is anything else you can do to make their experience better and if they can think of any way you or the company could improve.
• Complete all call notes, finish timesheet entry, and tidy up your van in preparation for the next call.

Bert also made a video of some of his top maintenance tips. If you stick to the procedure above and apply the tips from the video below, it'll probably be pretty hard to go wrong with your PMs.

—Bryan

P.S. – Since publishing this article the first time, I've been asked how long we “give” to do it. With a maintenance procedure this thorough, the time it takes will vary a lot and can be done in 45 mins on a new clean unit all the way up to 2 hrs.