Crestline Diffuser Schedule / SMACNA

Crestline BAS Specification

Despite the RTDs being more accurate, they do not meet the specification. The spec requires 10K ohm Type 2 thermistors, not RTDs. This is not about accuracy — it is about standardization and interchangeability. If the building uses 10K Type 2 thermistors throughout, any sensor can be replaced with any manufacturer's 10K Type 2 product without reprogramming the controller. RTDs have a different resistance curve, different wiring (often 3-wire or 4-wire vs. 2-wire), and require different analog input configuration. Mixing sensor types creates a maintenance nightmare.

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

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.

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.