11.1 Preventative Maintenance Programs & Service Agreements
Key Takeaways
- A preventative maintenance program is a written, scheduled task list tied to equipment type and run hours, not an annual sales visit with a clipboard.
- The three common service agreement structures are inspection-only, inspection plus discounted labor and parts, and full-coverage labor and parts, and each shifts a different amount of failure risk to the contractor.
- Full-coverage agreements must be priced from historical failure data, because the contractor absorbs the cost of every covered breakdown for the term.
- Agreement customers should be scheduled in the shoulder seasons, which converts idle spring and fall labor into billable revenue and levels the annual labor curve.
- Every visit must produce a written report with measured values - amperage, temperature split, static pressure, superheat or subcooling - because measurements are what justify the renewal.
11.1 Preventative Maintenance Programs & Service Agreements
[!NOTE] Maintenance is the second-largest technical block on the Alabama HAC blueprint. It is tested from two directions: the procedural side covered here - what gets checked, how often, and under what agreement - and the diagnostic side covered in the troubleshooting sections. Do not skip this half because it feels less technical; the questions are specific.
Why Planned Maintenance Wins
A dirty condenser coil raises head pressure, raises compression ratio, raises discharge temperature, and lowers capacity and efficiency all at once. The same neglected system fails in July, at overtime rates, with the customer angry and a compressor on back order. Planned maintenance moves that labor to April and converts an emergency into a scheduled hour.
| Failure driver | What planned maintenance does |
|---|---|
| Restricted airflow from loaded filters | Scheduled filter changes sized to actual loading, not a calendar guess |
| Fouled condenser coil | Annual chemical cleaning before the cooling season |
| Plugged condensate drain | Annual clearing plus float switch verification, critical in Alabama humidity |
| Loose electrical connections | Torque check and infrared or amperage comparison |
| Belt and bearing wear | Tension, alignment, and lubrication on schedule |
| Refrigerant leakage | Trended superheat, subcooling, and charge weight |
Scheduling: Calendar, Run Hours, or Condition
- Calendar-based - the default for residential split systems: one cooling visit in spring, one heating visit in fall.
- Run-hour-based - correct for commercial equipment with variable duty. A rooftop unit serving a restaurant kitchen may accumulate three times the compressor hours of an identical unit on an office suite.
- Condition-based - triggered by measurement. A rising filter pressure drop, a falling temperature split, or a climbing compressor amperage schedules the visit.
Most contractors run a hybrid: calendar visits for the base program, with run-hour intervals on belt-driven and commercial equipment.
Seasonal Task Lists
Cooling Season Visit (Spring)
- Replace or clean filters; record the size and the pressure drop across the filter.
- Wash the condenser coil from the inside out; straighten fins.
- Clean the evaporator coil face and check for biological growth.
- Flush the condensate drain line and pan; verify the trap and the float switch operate.
- Inspect and tighten all electrical connections; verify contactor points are not pitted.
- Measure and record compressor and condenser fan amperage against nameplate RLA and FLA.
- Measure and record capacitor microfarads against the rated value.
- Record suction and discharge pressures, superheat and subcooling, and the supply-to-return temperature split.
- Verify condensate pump operation and check the safety switch.
- Confirm the thermostat calibration and staging.
Heating Season Visit (Fall)
- Replace or clean filters.
- Inspect the heat exchanger visually and, where accessible, with a camera; document any suspicion of a crack.
- Clean the burners and the flame sensor; record the flame-sensor microamp signal.
- Verify manifold gas pressure against the rating plate and measure temperature rise against the nameplate range.
- Perform a combustion analysis; record carbon monoxide and record draft on Category I appliances.
- Verify the operation of the high-limit, rollout, and pressure switches.
- Inspect the vent connector for corrosion, proper rise, and secure joints.
- On heat pumps, verify defrost initiation and termination and confirm auxiliary heat staging.
- Test the condensate neutralizer and trap on condensing furnaces.
- Confirm carbon monoxide alarms are present and functional.
The Three Agreement Structures
| Structure | What the customer buys | Who carries breakdown risk | Typical pricing basis |
|---|---|---|---|
| Inspection only | Two scheduled visits, filters, cleaning, a written report | Customer pays for all repairs | Labor hours plus materials plus margin |
| Inspection plus discount | The visits, plus a stated discount on repair labor and parts and priority scheduling | Customer, at a reduced rate | Inspection cost plus the expected value of the discount |
| Full coverage | The visits plus covered repair labor and parts for the term | Contractor | Inspection cost plus historical repair cost per unit plus risk margin |
[!WARNING] Full coverage is an insurance product. Selling it without failure data is gambling. Price it from the actual repair history of that equipment class and age, exclude what you cannot control - refrigerant lost to a leak the customer refuses to repair, damage from a customer-installed thermostat, acts of nature - and state a per-occurrence or annual cap. Never write full coverage on equipment you have never inspected.
Agreement Terms That Belong in Writing
- Equipment covered by make, model, and serial number.
- Number, scope, and season of visits.
- Exactly what is included and excluded; refrigerant is the most-litigated line.
- Response-time commitment and after-hours rates.
- Term, price, payment schedule, escalation, and renewal or cancellation mechanics.
- A clause requiring the customer to authorize recommended repairs, or coverage suspends.
Why Agreements Are Worth Selling
- They level labor. Alabama demand collapses in April and October. Agreement visits fill those weeks with billable work, which stabilizes payroll and reduces the pressure to lay off trained technicians.
- They generate replacement leads. A technician standing in front of a fifteen-year-old condenser with a documented performance trend is the most credible replacement salesperson a contractor has.
- They create predictable revenue. Deferred agreement revenue recognized over the term smooths the income statement and supports a line of credit.
- They lift close rates on repairs. An agreement customer already trusts the contractor and has already been told the condition of the equipment.
Documentation That Makes the Program Real
Every visit ends in a written report containing measured values, not adjectives:
| Measurement | Cooling visit | Heating visit |
|---|---|---|
| Supply and return dry-bulb, temperature split | Required | Required (temperature rise) |
| Suction and discharge pressures | Required | Heat pump only |
| Superheat and subcooling | Required | Heat pump only |
| Compressor and fan amperage vs. nameplate | Required | Required |
| Capacitor microfarads vs. rating | Required | Required |
| Static pressure across the air handler | Required | Required |
| Manifold gas pressure and temperature rise | - | Required |
| Combustion analysis and carbon monoxide | - | Required |
| Filter size and condition | Required | Required |
The report goes to the customer, and a copy stays in the job file. That file is what supports the renewal, what defends the contractor if the equipment later fails, and what feeds the failure data that lets full-coverage agreements be priced honestly.
A contractor is deciding how to price a full-coverage service agreement on a fleet of eight-year-old rooftop units it has never serviced. What is the correct approach?
Two identical 7.5-ton rooftop units are installed on the same building, one over an office suite and one over a commercial kitchen. Which maintenance scheduling method best fits this situation?
Why does a maintenance report that records the measured temperature split, static pressure, compressor amperage, and capacitor microfarads have more business value than one that records "system operating normally"?