Replace a Service Valve (Condenser)

Replace a leaking/stripped service (ball/king) valve at the condensing unit: recover the charge, braze the new valve in with flowing nitrogen while heat-sinking the valve body, install a new liquid-line drier, nitrogen pressure-test, deep-evacuate, recharge, and verify both the Schrader core port and the valve seat hold.

Approx. 150 min

Before you start

•Confirmed the leak/fault is the valve — a stripped stem, a leaking valve seat (won't front-/back-seat), or a damaged Schrader/port. Bubble-test and confirm it isn't just a loose Schrader core or cap before opening the system.
•EPA 608 certified; recover the charge before applying any heat.
•Correct replacement valve: matched line size and connection (sweat vs flare), the right body style (ball/king) for the unit, with a service port.

Tools & materials

Recovery machine + DOT cylinder + scale · Brazing torch + rod, nitrogen + regulator (flow purge AND pressure test) · Wet rags / heat-sink compound, tube cutter, Schrader/core tool · New liquid-line drier, vacuum pump + micron gauge, charging scale + refrigerant

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Isolate & recover

Confirm the valve is the leak, then recover
Bubble/electronic-test the valve body, stem packing, and Schrader. Rule out a loose core or cap first. Once confirmed, recover the full charge per EPA 608 before any heat.
Tools: Recovery machine + cylinder, Schrader/core tool
⚠ Never braze on a pressurized system. Venting is illegal — recover first.
Cut the old valve free
Cut the line at the valve (cutter, not unbraze in place where possible) leaving enough clean stub to braze the new valve. Note orientation and the service-port direction.
Tools: Tube cutter

Braze the new valve

Install a new liquid-line drier
With the system open, install a fresh liquid-line drier, flow arrow correct — anytime the system is opened the drier is replaced.
Tools: New liquid-line drier
Target: New drier, flow arrow correct
Braze with flowing N2 and heat-sink the valve body
Wrap the valve body / any internal seat seals in a wet rag or heat-sink compound and keep the flame moving — a service valve has elastomer seats and packing that cook under too much heat. Flow a trickle of dry nitrogen while brazing so no oxide scale forms inside.
Tools: Wet rags / heat-sink compound, Nitrogen + regulator, Brazing torch
Target: Heat-sink the valve body; keep the flame moving; low flowing-N2 purge during the braze
⚠ Overheating warps the seat / burns the packing. Never trap N2 between closed points while heating. Fire watch.

Pressure-test, evacuate, charge & verify

Nitrogen pressure-test, then deep-evacuate
Pressurize with dry nitrogen and confirm no pressure drop BEFORE pulling a vacuum (never use the vacuum to find leaks), then evacuate to a deep vacuum with a decay hold.
Tools: Nitrogen + regulator, Vacuum pump, Micron gauge
Target: N2 pressure test holds; then evacuate ≤ 500 microns and hold
Recharge and verify the Schrader + seat
Weigh in the nameplate charge, run the system, and verify SH/SC. Then confirm the new Schrader core seals (no leak with the cap off), the valve front-/back-seats correctly, and bubble-test the brazes and the stem one final time.
Tools: Charging scale, Digital manifold + temp probes, Schrader/core tool
Target: Charge to nameplate, SH/SC in range; Schrader + seat + brazes all leak-free