Stop no-cool callbacks before Monday morning.
Your tech walks in, sees compressor amps 9.4 on a 12.0 unit, contacts pitting, a 29 µF capacitor reading 35. The assistant returns ranked causes — low charge, capacitor µF droop, contactor pitting — before the tech unloads the truck.
> COMPRESSOR AMPS ..... 9.4 / 12.0 > CAPACITOR µF ........ 29.1 / 35.0 > DELTA-T (RETURN) .... 4.1 °F (LOW) > CONTACTOR ........... ARC @ PULL-IN > FAULT ............... LOW CHARGE
Indicative readout · illustration only · not a real ticket.
From the bench
The three calls we’re getting this week.
Anonymised cases from the bench tape. Numbers and operators illustrated; copy lifts a typical HVAC fault so you can picture where the diagnostic lands on your own tickets.
- SHOP AANONYMISED · ILLUSTRATIVE
Symptom: No-cool callback after a humid 4 a.m.
> COMPRESSOR AMPS ..... 8.6 / 12.0 (LOW) > DELTA-T ............. 3.8 °F (LOW) > SUCTION PSI ......... 62 (LOW) > CONDENSER AIR ....... AMBIENT + 6 °F
Ranked causes
- 01LOW REFRIGERANT CHARGE71%
- 02EVAP COIL FROST-UP19%
- 03BLOWER FAILURE10%
Bench move: leak-search on the liquid line at the liquid-line drier; weigh in the charge; pull a wet-bulb reading before declaring.
- SHOP BANONYMISED · ILLUSTRATIVE
Symptom: Compressor hums, won't start, contactor arcing.
> CAPACITOR µF ........ 19.4 / 35.0 (LOW) > COMPRESSOR AMPS ..... 0.2 / 12.0 > CONTACTOR ........... ARC @ PULL-IN > RELAY STATE ......... CLOSED-WET
Ranked causes
- 01DUAL-RUN CAPACITOR µF DROOP74%
- 02CONTACTOR PITTING17%
- 03HERM SHORT TO GROUND9%
Bench move: meter the MFD µF cold, not at the unit — a hot capacitor can read back in spec and fail on the next pull-down.
- SHOP CANONYMISED · ILLUSTRATIVE
Symptom: Heat-only when it's 12 °F outside.
> GAS PRESSURE ........ 7.0 in wc (HI) > FLAME SENSE µA ...... 0.6 / 4.0 (LOW) > LIMIT SWITCH ........ OPEN @ 240 °F > INDUCTOR DRAFT ..... -0.04 in wc
Ranked causes
- 01FLAME SENSOR OXIDATION63%
- 02PRESSURE SWITCH FAILURE23%
- 03EXHAUST BLOCKAGE14%
Bench move: clean the flame rod with #000 steel wool (not sandpaper), re-light, watch the µA climb past 4.0 over three heat cycles.
How SecondShift fits
It lives where your HVAC dispatch already is.
The diagnostic assistant surfaces inside the FSM your trucks already run on. No new app to open, no new login for the tech — same ticket, same notes panel, with the bench tape injected in the right place per vendor.
- ServiceTitanSURFACES HERE
Inside the Job Notes panel on the dispatch card
Runs as a side panel below the tech’s voice note. Probable causes and the bench verdict land inline with the customer-history block you already scroll past.
- Housecall ProSURFACES HERE
On the custom fields of the dispatch card
Three custom fields get populated per ticket: ranked cause #1, parts list, bench verdict. The tech never opens another window.
- JobberSURFACES HERE
In the visit-notes tile on the job detail view
Pins as the bottom tile on the job — above the customer’s signature line and below the photos so the dispatcher sees it first thing Monday morning.
- FieldEdgeSURFACES HERE
On the work-order form, just below the symptom dropdown
Renders the ranked causes under the existing service-type selector. The tech’s existing checklist stays exactly where it is.
- Dynamics 365 Field ServiceSURFACES HERE
On the booking timeline, as a custom control activity
Attaches to the work order as a custom control activity so the existing Power Automate rules can route it onward without rebuilding dispatch logic.
Pick the FSM your trucks run on. Send the setup brief.
Four fields, an owner reads every one. Tool-tape + bench-verdict config for the HVAC line starts the day we agree to scope.
// Pre-tag the setup brief
Pick the dispatch platform your trucks already run on, then send the setup brief. The intake lands on the desk already pre-tagged with vertical=HVAC and your FSM — no replay needed.
Current field-service platform
// vertical=HVAC tagged · dispatchSoft=ServiceTitan selected above
Read next → The same cost math on repeat warranty rolls shows up across the trades — see the bench playbook on tankless E11 callbacks.
// Signoff
— secondshift-3. Tradespeople reading dispatch tickets since ’98. We will tell you straight if your HVAC line is not a fit for the $997 setup; if it is, we will tell you when the bench can take your first call.