Type II leak detection & inspections: EPA 608 Practice Questions

Which visible sign most often points to a refrigerant leak on a split system?

Escaping refrigerant carries compressor oil, which leaves an oily film where the leak is. Condensate dripping is normal.

A TXV system shows low suction pressure, high superheat and low subcooling. What is the most likely problem?

Low charge starves the evaporator (high superheat) and leaves little liquid in the condenser (low subcooling). Find the leak before adding refrigerant.

When pressure-testing a system with nitrogen, what limits the test pressure?

Never exceed the test pressure on the nameplate (often a lower value for the low side). Use a regulator and relief valve on the nitrogen cylinder.

Which approach finds a leak fastest on a large rooftop unit?

An electronic detector narrows the search quickly; bubble solution then shows the exact spot. A vacuum test proves a leak exists but not where.

When should fluorescent dye be used for leak detection?

Dye stays in the system and some manufacturers do not allow it. Check approval first; then a UV light shows where dye escapes with the oil.

Under the Section 608 definition of a leak inspection, how must a method that detects a leak but cannot locate it be used?

Methods such as a standing pressure test that show a leak exists must be combined with a method that finds where it is, such as bubbles or an electronic detector.

Where should a leak search start on a system that keeps losing charge?

Most leaks occur at mechanical joints, Schrader cores, brazed joints and places where tubing rubs or vibrates.

What can replace the periodic leak inspections required for some large appliances under 82.157?

An automatic leak detection system that meets the detection and alert standards in 82.157(g)(4) can be used instead of periodic inspections.

After a 60-lb R-22 comfort cooling unit exceeds its leak-rate threshold, how often must it be inspected for leaks?

Comfort cooling and other appliances are inspected annually until they show one year under the threshold.

A supermarket system holds 800 lb of R-22 and has exceeded the leak-rate threshold. How often must it be inspected for leaks?

Commercial refrigeration or industrial process appliances with 500 lb or more are inspected quarterly until four consecutive quarters are under the threshold.

A restaurant walk-in system with 120 lb of R-22 exceeded its threshold. How often must it be inspected for leaks?

Commercial refrigeration from 50 to under 500 lb is inspected once a year until it shows one year under the threshold.

Under 82.157, when must the leak rate of a covered appliance be calculated?

The leak rate is calculated every time refrigerant is added, with limited exceptions such as just after a retrofit or a seasonal variance.

Why is a standing vacuum test alone not enough to find a leak?

A rising vacuum reading confirms a leak (or moisture), but a locating method is still needed. A vacuum test also does not stress joints the way pressure does.

An ultrasonic leak detector is useful on a pressurized system because it can detect leaks of which gas?

Ultrasonic detectors hear the sound of gas escaping, so they work with nitrogen pressure tests and any refrigerant.

Who must perform a required leak inspection under 82.157?

Required leak inspections are done by a certified technician, who checks all visible and accessible components.