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EVT Ambulance

E3 Ambulance HVAC — practice test

Studying for E3 (Ambulance HVAC)? Overhaul Prep has 241 verified E3 questions written to the current task list — in the same formats the real exam uses (direct, Technician A/B, EXCEPT and most-likely-cause). Every answer comes with a written explanation, so you learn why instead of memorising a letter.

241E3 questions
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9,711questions in total
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Sample E3 questions

Straight from the bank — answers highlighted, with the explanation underneath.

In an ambulance A/C system, which component absorbs heat from the patient-compartment air and causes the refrigerant to change from a liquid into a low-pressure vapor?

  1. Condenser
  2. Evaporator
  3. Receiver-drier
  4. Compressor
WhyThe evaporator is the low-side heat exchanger where liquid refrigerant boils off, absorbing heat from the compartment air blown across it. The condenser does the opposite job (rejecting heat) on the high side, and the compressor and drier do not exchange heat with cabin air.

Two technicians discuss refrigerant handling on an ambulance. Technician A says that under EPA Section 609 a technician must be certified to service motor-vehicle air conditioning systems. Technician B says that because R-1234yf has a very low global warming potential, it is acceptable to vent it to the atmosphere instead of recovering it. Who is correct?

  1. Technician A only
  2. Technician B only
  3. Both Technicians A and B
  4. Neither Technician
WhyEPA Section 609 certification is required to service mobile A/C refrigerant, so Technician A is right. Venting refrigerant is prohibited under the Clean Air Act regardless of GWP; it must always be recovered, so Technician B is wrong.

A patient-compartment vent gives off a musty, moldy smell most strongly right after the AC/blower is switched on. The MOST likely cause is:

  1. Refrigerant overcharge in the AC system
  2. A plugged evaporator-case drain and microbial growth on the damp evaporator core
  3. A cracked exhaust manifold on the chassis engine
  4. A cabin filter with too low a MERV rating
WhyStanding condensate from a blocked evaporator drain plus biofilm on the wet, cold evaporator produces a musty smell that is worst when airflow first passes over the core. Overcharge, an exhaust crack, or filter MERV would not create a mold/musty odor.

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