Brand-new system, no refrigerant: the Teflon tape mistake

The homeowners had just moved into this newly renovated house in Torrance, and the HVAC system was brand new. But the system was not cooling, because the entire refrigerant charge had leaked out.

Plumbing tape on refrigerant fittings

The installer had used plumbing PTFE Teflon tape on the refrigerant-line flare connections. Plumbing tape cannot seal this type of connection — a flare seals metal to metal — so the fittings were never properly sealed. The electronic leak detector was sounding right at the leaking connection. The equipment was new, and the complete charge still escaped through those fittings.

Sealing the fittings correctly

I removed the tape, installed FlareTite gaskets, and applied Nylog Blue to seal the fittings correctly. Both went on before the fittings were tightened, in place of the plumbing tape that had been there.

The bubble test

Before recharging the system, I checked every connection with a bubble test. For that test, I used a foaming dispenser with diluted dish soap or shampoo. It creates thick, stable foam, and small leaks around the fittings become much easier to see.

A deep vacuum: 210 microns

After the bubble test, I pulled the system down into a deep vacuum. It reached 210 microns and held, which showed the repaired connections were no longer leaking.

Recharge and operating pressures

I recharged the system with nine pounds of refrigerant and checked the operating pressures. The pressures were normal, the unit was cooling, and everything was working properly.

New equipment still needs sealed connections

The system was new. The leak came from the way the connections had been sealed. On this job, the leak was at the refrigerant-line flare connections.

We repair HVAC systems and appliances across the Westside, Hollywood and the San Fernando Valley. Flat rate upfront, and the $85 service call is credited toward the repair. Call or text (213) 205-2055.