CCP CCP Plumbing & Mechanical Systems

Question 1

During commissioning of a domestic hot water (DHW) system, what minimum temperature must storage water be maintained at to prevent Legionella growth per ASHRAE 188?

Accepted Answer

140°F (60°C)

Answer

ASHRAE 188 requires domestic hot water storage at or above 140°F (60°C) to prevent Legionella bacteria proliferation, a critical public health concern verified during commissioning.

Question 2

What is the primary purpose of commissioning a domestic water pressure-reducing valve (PRV)?

Accepted Answer

To confirm the PRV maintains downstream pressure within the design range under varying flow conditions

Answer

A PRV commissioning check confirms the valve modulates correctly to maintain design downstream pressure (typically 60–80 psi) under both low-flow and high-flow conditions.

Question 3

A commissioning agent is verifying a hydronic heating system. What does 'delta-T' refer to, and why is it significant?

Accepted Answer

The temperature difference between supply and return water, indicating heat transfer efficiency

Answer

Delta-T is the temperature difference between supply and return water in a hydronic loop; a low delta-T indicates poor heat transfer or excessive flow, reducing system efficiency and capacity.

Question 4

What is the purpose of a backflow preventer, and what commissioning test confirms its function?

Accepted Answer

It prevents contaminated water from flowing back into the potable supply; tested by a certified backflow preventer test

Answer

A backflow preventer protects the potable water supply from contamination; commissioning requires a certified tester to perform a differential pressure test per local code requirements.

Question 5

During commissioning of a chilled water system, why is air purging of the hydronic loop critical?

Accepted Answer

Trapped air causes pump cavitation, reduced flow, noise, and poor heat transfer in hydronic coils

Answer

Air trapped in hydronic systems causes pump cavitation, reduces flow capacity, creates noise, and degrades coil heat transfer performance, all of which must be eliminated before functional testing.

(CCP) Certified Commissioning Professional Practice Test

(CCP) Certified Commissioning Professional Practice Test

CCP CCP Plumbing & Mechanical Systems