How To
Field procedures. Not a substitute for the OEM book or a 608 card.
Charge · 18 min
Charge an R-32 air conditioner
Weigh it. Stabilize it. Do not treat R-32 like a 410A top-off. A2L rules are the job, not a footnote.
Recovery · 14 min
Recover refrigerant
Identify the gas, stay under 80% of the tank, pull the cores, weigh everything. Mixing refrigerants is how you scrap a bottle.
Vacuum · 16 min
Pull a vacuum on a new unit
Cores out. Gauge on the system, not the pump. Decay is the test. Hitting 500 microns with the pump still running proves almost nothing.
Brazing · 12 min
Braze copper with nitrogen
Purge first, then a whisper of flow. POE oil will strip the oxide you leave inside the pipe and park it in the TXV.
Electrical · 10 min
Change a run capacitor
Prove 0 VAC, discharge it, match µF, terminals up. A weak cap cooks compressors. A screwdriver spark on A2L is the wrong habit.
Safety · 10 min
Nitrogen tightness test
Pressure is the leak test. Vacuum is the moisture test. Do not skip nitrogen and hope the micron gauge will confess.
Charge · 12 min
Weigh in a new split (any refrigerant)
Nameplate plus liquid-line feet. The charging chart is a trim, not a substitute for the scale.
Safety · 12 min
Find a refrigerant leak
Soap what you can see. Electronic for what you cannot. UV dye is a last, documented choice — not a first spray.
Electrical · 16 min
Walk a rooftop economizer
The damper can cool the building without the compressor — or kill capacity with the compressor running. Blade vs command first. Gauges last.
Electrical · 14 min
Troubleshoot a rooftop indoor-fan VFD
Enable 24V, then 0–10 V, then the drive code. OC is static or a seized wheel. Do not jumper fan-prove. Do not throw a dual cap at a VFD motor.
Electrical · 8 min
Read furnace and rooftop flash codes
A flash count is not a two-digit and not a 7-seg E. Goodman 3-flash is not Lennox 3-flash is not a Carrier IGC 3-flash. Count the group, then open THIS door card.
Electrical · 8 min
Read Carrier two-digit furnace codes
Three blinks, pause, one blink is 31 — not Goodman 3-flash. A VS display of 3 1.6 is often live CFM, not a fault. 33 hardens to 13; 34 hardens to 14. Bryant 926T speaks this chart; Infinity 31 is a pressure band.
Electrical · 10 min
Test a furnace pressure switch
The switch is a witness, not the vent. Inducer off = open. Inducer on = closed. Ohm it out of the harness. Do not leave a jumper on a draft switch.
Electrical · 9 min
Read Infinity / Evolution wall-control errors
The wall control is the diagnostic — Last 10 events in English. Board two-digit is backup when the screen is blank. C is still required. D is not W. 59TP6 will not become Infinity because you hung this thermostat.
Electrical · 7 min
Carrier code 32 — which 32 you have
Furnace 32 is draft (usually low-fire). Outdoor 32 is a suction pressure switch. Comfort 96 may use 32 as the only PS. Infinity modulating does not have a 32 to replace. A 3 1.6 CFM readout is not 32.