EPA 608 common mistakes
EPA 608 · Understand the traps and how to avoid them.
On a small-appliance job, the candidate selects 'system-dependent' (self-purging) recovery and pulls the charge with the appliance's own compressor, even though the compressor is seized, burned out, or the unit is being scrapped non-running.
They memorize 'small appliances may be recovered with system-dependent equipment' as an unconditional rule and never check the precondition that the appliance compressor must actually operate.
What to do instead
Verify the compressor runs before choosing the method. If it does not, switch to a self-contained recovery machine and recover to the required percentage/vacuum level. System-dependent equipment depends entirely on a working appliance compressor.
Recites '80% or 90%' for small-appliance recovery without attaching the November 15, 1993 date, then picks the wrong number when the question supplies the date.
Two percentages that differ by only ten points get stored as a jingle; the date is the only thing that distinguishes them, so it drops out of memory first.
What to do instead
Store them as a dated pair: recovery equipment from before 11/15/1993 to 80%, equipment from after 11/15/1993 to 90%, with evacuation to 4 in. Hg vacuum as the alternative. Say the date out loud with the number every time you review.
Classifies a rooftop split system, a field-assembled walk-in, or a 3-ton residential condensing unit as Type I work because the equipment 'looks small.'
The word 'small' invites a size judgment, and candidates forget the regulatory definition is about charge amount and construction, not physical dimensions.
What to do instead
Apply the definition: a small appliance is factory-charged, hermetically sealed, and holds 5 lb or less of refrigerant. Anything field-assembled, or holding more than 5 lb, is a Type II high-pressure appliance no matter how compact it is.
On Type II work, names 500 microns, 0 psig, or 'a full vacuum' as the target when recovering refrigerant from a high-pressure appliance.
Deep-vacuum dehydration numbers from installation practice bleed into the recovery question, which uses a different and much less stringent target.
What to do instead
Separate the two ideas. The 608 recovery target for high-pressure appliances is 90% of the charge (80% for older recovery equipment) or evacuation to 4 in. Hg vacuum. 500 microns belongs to evacuating a system for moisture removal before charging, not to recovering refrigerant.
Charges R-410A or R-407C into a system as a vapor, or answers 'vapor' when asked how a blended refrigerant should be charged.
Habit carried over from single-component R-22 charging, where vapor charging is acceptable; the candidate does not connect the word 'blend' to fractionation.
What to do instead
Blends are zeotropic and must be charged as a liquid so components enter in the designed ratio. If liquid cannot safely enter the suction line, throttle liquid in through a metering device. Never vapor-charge a blend.
States that R-410A, R-134a, or other HFC/HFO refrigerants may be vented because they are not ozone-depleting.
The ozone-depletion story dominates study time, so the venting prohibition gets mentally filed under 'CFCs only' and never gets extended to substitutes.
What to do instead
The Section 608 venting ban covers ozone-depleting refrigerants and their substitutes, including HFCs and HFOs. Venting is permitted only under the narrow listed exceptions, such as de minimis releases during good-faith repair attempts.
Answers that a leak on an R-123 chiller lets refrigerant escape into the room and that the main consequence is losing refrigerant charge.
Intuition imported from high-pressure systems, where internal pressure sits above atmosphere; candidates do not register that low-pressure machines run in a vacuum.
What to do instead
Low-pressure chillers normally operate below atmospheric pressure, so a leak draws air and moisture in rather than refrigerant out. The real damage is moisture-driven acid formation and lost capacity from non-condensables, which is why purge units and leak checks get so much attention.
Applies the high-pressure 4 in. Hg vacuum target when asked how far a low-pressure appliance must be evacuated before being opened.
One vacuum number is learned early in the course and then reused for every appliance class, because the candidate never noticed the recovery table has separate rows.
What to do instead
Learn the low-pressure row as its own entry: Type III appliances have a far deeper evacuation requirement than the 4 in. Hg used for high-pressure equipment. Whenever a question names R-11, R-113, or R-123, expect the low-pressure vacuum level, not the high-pressure one.
Uses 'recover,' 'recycle,' and 'reclaim' interchangeably - for example, saying a technician reclaims refrigerant on-site with a recycling machine, or that recycled refrigerant may be sold or put into another customer's equipment.
The three verbs sound like synonyms and always appear together in the same study paragraph, so they collapse into one fuzzy concept.
What to do instead
Anchor one sentence each: recover = remove and store; recycle = clean on-site for reuse in the same system or the same owner's equipment; reclaim = reprocess off-site to ARI-700 new-product purity, the only route that makes refrigerant usable in another owner's equipment.
Mixes up the leak-repair thresholds or the repair window - for example, applies the 20% commercial-refrigeration trigger to a comfort-cooling unit, or allows 60 days to fix a leaking appliance.
Three percentages and one deadline are taught together where only the appliance category changes, so the numbers drift out of their slots under exam pressure.
What to do instead
Recite category-percentage pairs, never a bare list: comfort cooling 10%, commercial refrigeration 20%, industrial process 30%, with repair required within 30 days of discovering a leak above the trigger. These obligations apply to appliances holding 50 lb or more of refrigerant.