Crestline Electrical Specification (THD ≤ 3%; cf. IEEE 519-2022 Table 2)

What it means on the job

The Crestline electrical specification caps total harmonic (voltage) distortion (THD) at the point of common coupling at 3% — stricter than the IEEE 519-2022 Table 2 voltage-distortion limits of 5% (1–69 kV) / 8% (≤1 kV total), where 3% is the individual-harmonic limit. At 4%, the installation exceeds the project's 3% cap. An active harmonic filter or multi-pulse drive configuration is required to bring THD into compliance.

Tested in 1 CraftIQ puzzle

  • whats-wrongVFD Harmonic Distortion Compliance
Practice this code — free

Related OTHER sections

Crestline BAS Specification / ASHRAE Guideline 13

Crestline specifications require that the building owner have full access to update, modify, and maintain all BAS components including controller firmware. Systems that require vendor involvement for routine maintenance violate the owner-access requirements of the specification.

Crestline BAS Specification / ASHRAE Handbook — Fundamentals

The probe insertion is inadequate. At 6 inches into a 36-inch duct, the probe extends only 17% into the duct width — well short of the required 25-50% (which would be 9-18 inches). A shallow probe reads the boundary layer temperature near the duct wall, which is influenced by heat gain or loss through the duct wall and does not represent the bulk airstream temperature. For a 36-inch duct, the probe should extend at least 9 inches (25%) and ideally 12-18 inches (33-50%) to read the core airstream temperature accurately.

Crestline Diffuser Schedule / SMACNA

The EA6X6 grille is rated for only 100 CFM per the Crestline schedule. Installing it on a 200 CFM exhaust point doubles the design velocity through the neck, creating excessive noise (well above NC-35 criteria for occupied spaces) and pressure drop far exceeding the 0.15" WG maximum. The correct grille is EA8X8-200, which has an 8"x8" neck sized for 200 CFM. Undersized grilles also cause the exhaust fan to work harder, increasing energy consumption and reducing fan life.

Crestline Electrical Specification (THD ≤ 3%; cf. IEEE 519-2022)

The Crestline electrical specification requires total harmonic (voltage) distortion (THD) at the point of common coupling to remain below 3% — stricter than the IEEE 519-2022 voltage-distortion limits of 5% (1–69 kV) / 8% (≤1 kV total). A 4% THD measurement exceeds the project's 3% cap, indicating insufficient harmonic filtering, which can overheat transformers, trip breakers, and damage sensitive electronics on the same bus.

Crestline Equipment Schedule

This installation is acceptable. The radiator WH-2 is operating near its schedule point at 119°F EWT and 101°F LWT (18°F delta-T) with 0.3 GPM flow. By energy balance, the heat the water gives up is exactly Q = 500 × 0.3 × 18 = 2,700 BTU/hr — that IS the radiator's actual heat output, not a 'theoretical' value. That is about 15% above the 2,339 BTU/hr scheduled output, so the unit is over-delivering slightly versus its design point. The gap is not a heat-transfer-coefficient effect: the coefficient and fin/air-side performance determine what delta-T you GET, but once flow and delta-T are measured the output is fixed by energy conservation. A modest over-delivery like this is normal and acceptable in the field.

Crestline Equipment Schedule / AHRI 1230

The measured values match the scheduled capacity exactly. FCU-B2-1-06 at 4.5 tons nominal delivers 52.7 MBH total and 45.9 MBH sensible cooling per the schedule. The sensible heat ratio (SHR) is 0.87 (45.9/52.7), indicating this indoor unit handles mostly dry cooling loads. The heating capacity of 68.9 MBH should also be verified during winter commissioning. The unit connects to outdoor unit HR-B2-R-01 (34-ton heat recovery), which serves multiple indoor units simultaneously.

CraftIQ explanations are original educational commentary written in trade language and verified against the cited standards. Always confirm requirements against the code edition adopted by your jurisdiction — this is training material, not a substitute for the code book or your AHJ.