ASHRAE Guideline 36 / Manufacturer maintenance requirements

ASHRAE Guideline 36 — Section 5.18

Sensors on exterior walls are influenced by solar gain and outdoor temperature conducted through the wall, producing inaccurate space readings. Mount sensors on interior walls per ASHRAE guidelines.

ASHRAE Guideline 36 — Sensor Placement

Temperature sensors must not be placed in direct airflow from supply diffusers. The supply air temperature causes false readings, making the controller unable to maintain proper space temperature setpoint.

ASHRAE Guideline 36 / Crestline Controls Specification

Duct temperature probes must be inserted 25-50% of the duct width to obtain a representative reading. Inserting only 10% places the sensor in the boundary layer near the duct wall where temperature is not representative of the airstream, causing inaccurate control.

ASHRAE Guideline 36 / Manufacturer Requirements

Chillers require a minimum runtime (typically 15-30 minutes) and minimum off-time (typically 15 minutes) to prevent compressor short-cycling. Frequent starts damage the compressor motor and reduce equipment life.

ASHRAE Handbook — Fundamentals, Chapter 7

A thermostat behind a door that is typically held open will be in stagnant air and will not sense the true space temperature. It must be in an area with representative airflow of the occupied zone.

ASHRAE Handbook — HVAC Applications

Rooftop units must have vibration isolation to prevent noise and vibration transmission to the building structure. Required by ASHRAE and most building codes.