CCP Systems & Equipment Performance 2

Question 1

A chilled water system is experiencing low delta-T syndrome. Which of the following conditions is the PRIMARY cause?

Accepted Answer

Control valves failing to modulate properly at part load

Answer

Low delta-T syndrome is most commonly caused by control valves failing to fully close at part load, allowing warm return water to mix with supply water.

Question 2

During performance testing of a centrifugal pump, the flow rate is lower than design. Which diagnostic step should be taken FIRST?

Accepted Answer

Verify actual pump curve against the system curve

Answer

Verifying the actual pump curve against the system curve identifies whether the issue lies with the pump itself or the system resistance.

Question 3

What is the significance of the 'equal percentage' characteristic in a control valve?

Accepted Answer

Each increment of valve stroke produces an equal percentage change in flow

Answer

An equal percentage valve produces a flow change that is a fixed percentage of the current flow for each increment of stem travel, providing good controllability at part load.

Question 4

When commissioning a variable air volume (VAV) system, the diversity factor is used to:

Accepted Answer

Determine the ratio of maximum simultaneous zone airflow to total installed terminal capacity

Answer

The diversity factor accounts for the fact that not all VAV terminals will be at maximum demand simultaneously, allowing the central AHU to be sized smaller.

Question 5

A cooling tower's approach temperature is defined as:

Accepted Answer

Difference between leaving cold water and entering wet bulb

Answer

Approach temperature is the difference between the tower's leaving cold water temperature and the ambient wet-bulb temperature, indicating tower effectiveness.

(CCP) Certified Commissioning Professional Practice Test

(CCP) Certified Commissioning Professional Practice Test

CCP Systems & Equipment Performance 2