No-Cool Emergency Call Response

Purpose

This standing instruction sets what a shop owes a customer with no cooling in hot weather: an occupant-risk decision made on the phone before anyone is dispatched, a diagnosis that measures rather than assumes, and an outcome by the end of the visit that the customer can act on tonight.

Two failures it exists to prevent. The first is the triage failure, where an 80-year-old in a house at 88 degrees waits four hours in the routine queue because nobody asked who lives there. Heat illness kills people indoors, and the call taker is the only person in the shop positioned to catch it. The second is the parts-cannon failure, where a tech replaces a capacitor because that is usually the answer, the system still does not run, and the customer has now paid for a part and still has no cooling.

Safety actions that gate the work

• If the caller reports anyone confused, not sweating in a hot house, or complaining of chest symptoms, tell them to call 911 and move to a cooler place immediately. Do not tell them a tech is on the way and leave it there. A dispatch is not a medical response.
• If the caller reports smoke, burning smell, sparking, or a breaker that trips again after one reset, instruct them to leave that breaker off and not to reset it again. A breaker that trips twice is doing its job on a fault that is still there.
• On arrival, open and lock the disconnect and prove dead before any cover comes off, using the live-dead-live sequence in NFPA 70E-2021, 120.5. Work on this utilization equipment is controlled by 29 CFR 1910.333(b)(2).
• Discharge run and start capacitors through a resistor and confirm with the meter. A capacitor sitting in an open cabinet all afternoon can still hold enough charge to injure.
• Attic and rooftop work in a heat event is its own hazard. Water in the truck, work in shorter cycles, and do not send one tech alone into an attic on a design day.

Scope

Covers residential and light-commercial cooling failures dispatched as same-day or after-hours emergencies, from the call taker's first question through the end-of-visit outcome.

Does not cover a system that runs but underperforms, which is a scheduled diagnostic rather than an emergency. Does not cover charge verification after a repair, owned by the commissioning SOP. Does not cover the leak-authorization decision when the fault turns out to be refrigerant loss, owned by the refrigerant leak response and repair authorization SOP; hand off to it rather than improvising a top-off.

Roles and handoffs

Procedure

1. Ask the occupant-risk questions before you book anything. Who is in the house (infants, anyone over 75, anyone with a heart or lung condition or on medication that affects heat tolerance), what the indoor thermometer reads now, and whether anything is smoking, smelling or tripping. Acceptance: three answers written on the ticket. Stop rule: any symptomatic occupant gets the 911 instruction and a cooler-place instruction first, and the ticket is escalated regardless of queue position.

2. Give interim instructions on that same call, before you hang up. Close blinds on the sun side, run ceiling and box fans, drink water, move to the lowest floor, and turn the thermostat to off rather than leaving it calling into a dead system. Acceptance: the instructions given are noted on the ticket. Wrong looks like ending the call with only an arrival window, which leaves a hot house getting hotter for the whole wait and gives the customer nothing to do.

3. On arrival, read the system's state before you touch a single control. Thermostat mode and setpoint against room temperature, whether the indoor blower is moving air, whether the outdoor fan and compressor are running, and the state of every breaker and disconnect. Acceptance: a written four-part state (call present or not, indoor running or not, outdoor running or not, power present or not). Wrong looks like immediately pulling the condenser cover, which throws away the one observation that tells you which side of the system to work on.

4. Confirm power and the call at the outdoor unit before you condemn any component there. Line voltage at the contactor line side, and 24 volts across the contactor coil when the thermostat is calling. Acceptance: both present. Stop rule: if there is no 24 volts at the coil, the fault is upstream in the control circuit and no part at the condenser gets replaced. Keep clear of the fan blade while metering with the disconnect closed, and use a meter and leads rated for the circuit.

5. Trace the control circuit from the transformer to the outdoor unit, terminal by terminal. Confirm secondary voltage at the transformer, then read voltage at each device in series on the cooling call, including any condensate float switch, low-pressure switch, or lockout board terminal. Acceptance: the exact device where the voltage disappears, named. Wrong looks like a shotgun thermostat replacement, which is what happens when the tech knows the call is missing but never finds where it stops.

6. Where a safety device is found open, establish why it opened before you treat it as the fault. A float switch, a high-pressure switch or a limit that is doing its job is evidence, not a defect. Acceptance: a named physical cause with the condition verified corrected. Stop rule: never jumper a safety to prove a diagnosis, and never replace one without a cause, because a new switch reaches the same failure a week later with a part number on the invoice. Do not clear a plugged drain with compressed air aimed toward an occupied space.

7. Decide the outcome before you pack up, and give it in three parts. Repaired now, repaired with a return needed, or not repairable today. Acceptance: the customer hears what is fixed, what is not, and what to do tonight. Where an at-risk occupant is in a house that will not cool by evening, escalate to the manager for temporary relief: a portable unit staged in the bedroom, a window unit, or a documented recommendation to stay elsewhere. Wrong looks like leaving a quote and an arrival window with no plan for the next twelve hours.

8. Write the outcome and the readings before you leave the driveway. Acceptance: the ticket carries the four-part state from step 3, the point where the call stopped, the cause of any open safety, the readings taken, and the interim plan. Wrong looks like "system down, needs part," which forces the next tech to re-run the whole diagnosis and forces the office to re-ask the customer questions already answered.

The record this produces

One emergency record per call, attached to the equipment:

• The three triage answers, the indoor temperature at the time of call, and the interim instructions given
• Arrival time, and the four-part system state as found
• Line voltage, control voltage at each device in series, capacitor readings against nameplate, amps against RLA
• Any safety device found open, and the named physical cause
• Work performed, parts used, and readings after repair
• The outcome given to the customer, and any temporary relief provided or declined

Dispatch reads the triage answers to order the day. The next tech reads the four-part state and the readings, which is what turns a repeat call into a five-minute confirmation instead of a fresh diagnosis. The manager reads the outcomes to find the systems the shop keeps rescuing and never quotes.

Worked pass: 96 F day, house at 88 F, occupant aged 81

Step 1: caller is the daughter, occupant is 81 and lives alone, indoor thermometer reads 88 F, nothing smells or trips. Not symptomatic. Escalated to the front of the queue over two earlier no-cool calls at unoccupied rentals.

Step 2: blinds, fans, fluids, lowest floor, thermostat off. Noted on the ticket at 13:20.

Step 3, arrival 14:10. Four-part state: thermostat calling for cool at 74 with the room at 88, indoor blower running and moving air, outdoor unit silent, breaker on and disconnect in.

Step 4 FAILS. Line voltage present at the contactor line side. Zero volts across the contactor coil with the thermostat calling. Stop rule taken: no capacitor swap, no contactor swap, no compressor judgment. The fault is upstream, so the work moves indoors.

Step 5: 24 volts at the transformer secondary. Voltage present at the air handler board's Y terminal, absent on the load side of the condensate float switch wired in series with Y. The device where the call stops is named.

Step 6: the float switch is open because the secondary pan holds standing water, and the primary drain is plugged with biofilm at the trap. Cause named and corrected: trap cleared, pan vacuumed, flow confirmed at the exterior termination, switch closes and the call passes through. The switch is not replaced, because nothing was wrong with it. This is the point of the step: a tech who jumpers that switch gets cooling in ninety seconds and a ceiling stain in September.

Step 7: system runs, and the split measures 18 F. Room temperature logged at 79 F at 16:05, down from 88 F at 14:10, a 9 F drop over 115 minutes. No temporary relief needed. Drain treatment and a float-switch test added to the maintenance recommendation.

Checking the pass against the sections above: step 4's acceptance condition is both line voltage AND 24 volts at the coil, and this pass reports one present and one absent, which is the failure that step's stop rule is written for. The room temperature figures are both dry-bulb readings at the same thermostat, taken 115 minutes apart, so the 9 F is a change at one location rather than a comparison between two different measurements.

References

• 29 CFR 1910.333(b)(2) for de-energized work on utilization equipment, and NFPA 70E-2021, 120.5 for the live-dead-live proving sequence
• CDC and NIOSH public guidance on heat illness recognition, for the symptoms a call taker should escalate on
• Manufacturer's wiring diagram for the specific air handler and condensing unit, for the devices in series on the cooling call
• See related: the commissioning a replacement condensing unit SOP, and the refrigerant leak response and repair authorization SOP