Using the nominal 400 CFM per ton, how much airflow does a 3-ton air conditioner need?
Answer in CFM.
Show the answer
1200 CFM
Airflow = tons x 400 CFM per ton = 3 x 400 = 1,200 CFM.
Reference: Nominal airflow per ton of cooling
TradeExamPro › HVAC & Refrigeration
215 free practice questions for this exam, each with the reason for the answer and where to look it up.
Beta. These questions are new. They were written and checked with AI and have not yet been reviewed by a licensed tradesperson. If one looks wrong, use “Report this question” and we will fix it.
10 questions, graded as you go, with the reason for every answer. No sign-up.
The refrigeration cycle, airflow, electrical and controls, heating and service practice, as tested on state HVAC licence exams and NATE-style certifications.
Diagnosis scenarios for air conditioners, heat pumps and gas furnaces: electrical faults, airflow, charge, ignition and controls.
| Exam | NATE air conditioning service and installation |
|---|---|
| Who runs it | NATE |
| Where | United States |
Question count, time limit and pass mark differ by where you take it. Check the official candidate bulletin from the organisation that runs your exam.
Using the nominal 400 CFM per ton, how much airflow does a 3-ton air conditioner need?
Answer in CFM.
1200 CFM
Airflow = tons x 400 CFM per ton = 3 x 400 = 1,200 CFM.
Reference: Nominal airflow per ton of cooling
A heating element with a resistance of 12 ohms is connected to 240 V. How much current does it draw?
Answer in A.
20 A
I = E / R = 240 V / 12 ohms = 20 A.
Reference: Ohm's law
An air conditioner delivers 36,000 Btu/h while drawing 3,000 W at the rating condition. What is its EER?
Answer in Btu/Wh.
12 Btu/Wh
EER = cooling output in Btu/h / power input in watts = 36,000 / 3,000 = 12.
Reference: Energy efficiency ratio
Tell us where and when you are taking it, and what you want more of. It decides what we write next.
EPA Section 608 (Core, Type I, II, III, Universal) · EPA Section 609 motor vehicle air conditioning · HVAC / mechanical journeyman · HVAC / mechanical contractor · NATE Ready-to-Work and HVAC Support · NATE heat pump service and installation · NATE gas heating service and installation · Refrigeration journeyman / operating engineer · RSES CM / CMS