INTRO (0:00 to 0:30)
Darrel at the condenser, micron gauge still connected, panel off.
DARREL: "This system just passed its decay test at 480 microns. The coil swap is done, the circuit is tight, and right now there is zero refrigerant in it. Today I am going to put the exact charge back in by weight, the way the factory intended, and then I am going to prove it with subcooling before this panel goes back on. No guessing, no feel, just arithmetic and a scale. Watch the order I do things in, because the order is the method."
ON-SCREEN: C17: Weigh-in plus verification. The gold standard
MAIN (0:30 to 10:00)
[0:30-1:45] Beat 1: Read the plate, out loud
Close-up: data plate. Darrel taps each field as he reads it.
DARREL: "Everything starts here. Refrigerant: R-410A, so that is the only cylinder that gets near this unit, and my probes get programmed to R-410A before anything connects. Factory charge: 8 pounds 12 ounces. And the fine print everybody skips: that charge covers 15 feet of line set. This plate also gives me a subcooling target of 10 degrees, and I am writing that down, because that is my proof at the end."
Camera holds on the plate while Darrel writes: 8 lb 12 oz / 15 ft / SC 10.
ON-SCREEN: Plate values overlaid: R-410A. 8 lb 12 oz. Includes 15 ft. Subcooling 10 F
[1:45-3:00] Beat 2: Measure the line set and do the math
Darrel walks the line set with the tape measure, camera following: up the wall, across the attic chase, down to the air handler. He narrates the measurement, then comes back to the truck tailgate and does the math on the notepad, full frame.
DARREL: "Forty feet of line set, and I walked it, I did not guess it. The liquid line is 3/8, and the rule of thumb when the manual is not in my hand is six tenths of an ounce per extra foot of 3/8 liquid line. The manual for this unit says the same thing, and the manual always wins, so let us do it. Forty minus fifteen is twenty five extra feet. Twenty five times point six is fifteen ounces. Eight pounds twelve ounces plus fifteen ounces, and careful here, twelve plus fifteen is twenty seven ounces, and a pound is sixteen ounces. So that is nine pounds, eleven ounces. That is my number. Not approximately. That."
ON-SCREEN: C17-lineset-adjustment-math.svg held for the full calculation
ON-SCREEN: TARGET CHARGE: 9 lb 11 oz
[3:00-4:30] Beat 3: Scale setup and the zero
Darrel sets the scale on a paver beside the unit, places the cylinder, connects and purges the hose, then zeroes.
DARREL: "Scale technique decides whether my nine eleven is real. Firm level surface, this paver, not the gravel. Out of the wind, behind the unit. Cylinder on, hose connected to the cylinder and the manifold, purged, and only NOW do I zero the scale. If I zero before the hose fills, the refrigerant sitting in that hose counts against my charge and never enters the system. From this moment, nobody touches the cylinder, nobody leans a hose on it. Every touch is a fake ounce."
Close-up: scale display zeroing. Darrel flips the cylinder upside down in its rack on the scale.
DARREL: "This jug feeds vapor upright and liquid inverted, no dip tube, says so right on the label. I want liquid, so it rides upside down. If you are on an A2L cylinder, a lot of those feed liquid sitting upright through a dip tube. Read your label, every cylinder, every time."
ON-SCREEN: C17-weigh-in-setup.svg
ON-SCREEN: Connect. Purge. THEN zero
[4:30-6:00] Beat 4: Liquid charge into the vacuum
Darrel connects to the liquid line port, opens the cylinder and the high side, and lets the vacuum pull liquid. Close-up alternates between the scale counting and the hose.
DARREL: "System is off and under vacuum, so I charge liquid, into the liquid line. Three reasons. Liquid is dense, so it moves fast. This port feeds toward the metering device, away from the compressor, so no liquid lands where the compressor sleeps. And liquid keeps the blend honest. R-410A is two refrigerants in one cylinder, and the vapor over the liquid is not the labeled mix. Pull vapor off a blend and you fractionate it. Liquid out of the cylinder is always the real recipe. Charge every blend as liquid and you never have to remember which ones forgive you."
Scale close-up: counting down, then slowing, then stopped at 7 lb 9 oz delivered.
DARREL: "And there it stalls. Seven pounds nine ounces in, and the system pressure has come up to meet the cylinder. The vacuum did its work. The last two pounds two ounces go in with the system running."
ON-SCREEN: Delivered: 7 lb 9 oz. Remaining: 2 lb 2 oz
[6:00-7:45] Beat 5: Throttle in the rest, running
Darrel closes valves, moves the hose to the suction side per his manifold setup, starts the system, and throttles. Close-up on the barely-cracked manifold valve, then the scale, then the suction line.
DARREL: "Compressor is running, suction pressure pulls down below cylinder pressure, and flow comes back. But now I am feeding the side that leads straight to a vapor pump, so this valve opens a crack, not a turn. Throttling. The liquid flashes to vapor in the hose and manifold before it reaches the port. Listen to the unit, watch the suction pressure rise gently, watch the scale walk down. If suction spikes or that compressor makes a sound I do not like, I close and let it settle. The last pound of a charge takes minutes. That is on purpose."
He feeds, pauses, feeds. Scale reaches 9 lb 11 oz. He closes the cylinder, then the manifold.
DARREL: "Nine pounds eleven ounces, on the nose. Cylinder closed first, then the manifold. The charge is in. Now I prove it."
ON-SCREEN: 9 lb 11 oz DELIVERED. Charge set by weight. Verification next
[7:45-9:15] Beat 6: Verify with subcooling, because this is a TXV
Darrel clamps the liquid line probe at the service valve, underside of the pipe, and the suction probe six inches from the suction valve, wrapped, exactly per F6. He waits on camera; a time-skip card covers the stabilization.
DARREL: "This unit has a TXV, so the verification method is subcooling, against the plate target of 10. If this were a piston unit, I would be reading the superheat chart with indoor wet bulb and outdoor dry bulb instead. The metering device picks the method, every time. System has run fifteen minutes, readings are holding still, so now I trust them."
ON-SCREEN: Time skip: 15 minutes of runtime
Close-up: probe readings.
DARREL: "Liquid pressure 390, and on R-410A that saturates at 115. Liquid line reads 105. One fifteen minus one oh five: 10 degrees of subcooling, dead on the plate. And superheat, my check on the valve, reads 11, right in the 10 plus or minus 5 window. The weight said the charge was right, and the readings agree. That is what done looks like. If subcooling had come back low or high after a correct weigh-in, I would NOT reach for the cylinder. The weight is known good, so a bad reading would be pointing at a restriction, the valve, or my own probes."
ON-SCREEN: 390 psig = 115 F sat. 115 - 105 = 10 F subcooling. Target: 10. Superheat check: 11 F
[9:15-10:00] Beat 7: Document it
Darrel at the tablet, filling in the record. Close-up on the notepad math one last time.
DARREL: "The job is not done until the next tech can reconstruct it. Into the record: R-410A, weighed in 9 pounds 11 ounces, plate charge 8-12 plus 15 ounces for 25 extra feet of line set, math shown. Final subcooling 10 against a plate target of 10, superheat 11, pressures, line temps, outdoor temp, indoor return temps. Photo of the plate, photo of the final readings. Two years from now this record answers every question before anybody asks it."
ON-SCREEN: The complete charging record, line by line as he enters it
OUTRO (10:00 to 10:30)
DARREL: "Three methods. Weigh-in when the circuit was opened or the charge is suspect, like today. Subcooling to trim a TXV. The superheat chart to trim a piston. The scale set this charge and the readings proved it, and that pairing, weight plus verification, is the standard. Your practical is exactly what you just watched: the math, the scale, the charge, the proof. Bring a calculator and respect the sixteen-ounce carry."
ON-SCREEN: Practical: compute, weigh in, verify, document