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10 free, exam-style Mechanical Acceptance Test Technician (MAT) (MAT) practice questions with answers and explanations. No signup required. Work through them below, then take the full free MAT practice test to study every exam domain.

Question 1

Every mechanical acceptance test in NA7.5 has two phases. A technician has confirmed the economizer high-limit sensor is the correct type, mounted per plans, and set to the right value, but has not yet driven the unit through any operating modes. Which phase still has to be completed before the test is finished?

  1. Construction inspection, which must be repeated once the controls contractor signs off the job
  2. Functional testing, operating the system through its control sequences to confirm performance
  3. Plan check, in which the local building department approves the written sequence of operations
  4. HERS field verification, in which an independent third-party rater confirms installed equipment
Show answer & explanation

Correct answer: B - Functional testing, operating the system through its control sequences to confirm performance

Question 2

A contractor wants to begin offering mechanical acceptance testing. What is the MINIMUM certified-personnel requirement the firm must satisfy?

  1. A licensed professional engineer on staff to stamp each Certificate of Acceptance the firm issues
  2. Two certified MATTs assigned to every county in which the firm intends to perform acceptance tests
  3. At least one certified MATE (the employer) and at least one certified MATT (the technician)
  4. An Energy Commission field representative who co-signs the firm's first ten completed acceptance tests
Show answer & explanation

Correct answer: C - At least one certified MATE (the employer) and at least one certified MATT (the technician)

Question 3

Three certificates accompany a nonresidential project: one states what the building was DESIGNED to do, one is signed by the installing contractor to confirm what was actually installed, and one confirms the systems were tested and perform correctly. Which is the acceptance test technician's deliverable?

  1. The NRCI, the Certificate of Installation
  2. The NRCC, the Certificate of Compliance
  3. The NRCV, the Certificate of Verification
  4. The NRCA, the Certificate of Acceptance
Show answer & explanation

Correct answer: D - The NRCA, the Certificate of Acceptance

Question 4

A 1,500 ft² conference room is designed for 40 people and is served by a single-zone unit with an air economizer. The design engineer asks whether demand control ventilation (DCV) is required here. The MOST accurate response is:

  1. Yes - the space is densely occupied and is served by a system with an economizer
  2. No - DCV applies only to spaces whose floor area is greater than 3,000 square feet
  3. No - any space served by an air economizer is specifically exempt from DCV controls
  4. Yes - but the requirement is waived whenever the room has any operable windows
Show answer & explanation

Correct answer: A - Yes - the space is densely occupied and is served by a system with an economizer

Question 5

During functional testing of a DCV system the technician simulates falling occupancy and CO₂ drops. As CO₂ decreases the outdoor-air damper modulates toward closed, but is required to stop at what point?

  1. Fully closed, so that essentially no outdoor air is admitted while occupancy stays low
  2. Wherever the damper happens to hold supply-air temperature at the cooling setpoint
  3. No lower than the code-required minimum ventilation rate for that space
  4. At the economizer minimum damper position that was recorded during the prior test
Show answer & explanation

Correct answer: C - No lower than the code-required minimum ventilation rate for that space

Question 6

Maintaining minimum outdoor air is generally harder to verify on a VAV system than on a constant-volume system. The PRIMARY reason is that:

  1. VAV systems are not permitted to use an outdoor-air economizer to provide free cooling
  2. Reducing total airflow at part load can drop the outdoor-air fraction below the minimum
  3. VAV systems have no return-air path, so all of the airflow must be read at the intake
  4. Constant-volume systems are entirely exempt from delivering any outdoor air at all
Show answer & explanation

Correct answer: B - Reducing total airflow at part load can drop the outdoor-air fraction below the minimum

Question 7

An economizer is set up to shut off whenever the outdoor air carries MORE total heat than the return air, accounting for both temperature and moisture. Which high-limit (changeover) control type is this?

  1. Fixed dry-bulb
  2. Fixed enthalpy
  3. Differential dry-bulb
  4. Differential enthalpy
Show answer & explanation

Correct answer: D - Differential enthalpy

Question 8

An air economizer is delivering free cooling, yet the zone still calls for additional cooling. For the system to pass, the controls should:

  1. Allow mechanical cooling to run together with the economizer (integrated economizer operation)
  2. Drive the outdoor-air dampers down to minimum and start mechanical cooling in their place
  3. Hold off all mechanical cooling until the economizer alone can no longer meet the load
  4. Switch the high-limit device from enthalpy changeover over to dry-bulb changeover
Show answer & explanation

Correct answer: A - Allow mechanical cooling to run together with the economizer (integrated economizer operation)

Question 9

While testing a single-zone packaged heat pump, the technician checks the auxiliary electric-resistance heat. Correct operation is confirmed when the auxiliary heat:

  1. Comes on with the compressor on every call for heating in order to shorten recovery time
  2. Runs continuously while in heating mode any time the outdoor temperature is below 50°F
  3. Stays locked out until the heat pump alone can no longer meet the heating load
  4. Takes over fully for the compressor once the outdoor temperature drops below setpoint
Show answer & explanation

Correct answer: C - Stays locked out until the heat pump alone can no longer meet the heating load

Question 10

A technician needs a direct airflow reading in cfm at a ceiling supply diffuser. Which instrument is the MOST appropriate?

  1. A Pitot tube run as a multi-point traverse in the duct upstream of the diffuser
  2. A flow hood (capture hood) placed directly over the face of the diffuser
  3. A clamp-on ammeter installed on the supply-fan motor leads to read the amperage
  4. A differential-pressure manometer connected across the air handler filter bank
Show answer & explanation

Correct answer: B - A flow hood (capture hood) placed directly over the face of the diffuser

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