ASHRAE 135-2016
What it means on the job
A BACnet gateway does not satisfy a native BACnet requirement. The specification explicitly requires BACnet per ASHRAE 135-2016 and prohibits proprietary protocols. A gateway creates a single point of failure, adds latency, limits functionality (not all BACnet services translate through gateways), and locks the owner into one vendor for the field-level devices. Native BACnet means every controller communicates BACnet natively — either BACnet/IP or BACnet MS/TP — without translation. This is a critical specification requirement designed to protect the building owner from vendor lock-in.
Tested in 1 CraftIQ puzzle
- code-checkBACnet Protocol Requirement
Related ASHRAE sections
ASHRAE 135 (BACnet) — Clause 9, MS/TP MAC addressing
MS/TP reserves MAC 255 for broadcast and 128-254 for slave devices; 127 is the very top of the master range. Parking a field controller at 127 forces max_master to its ceiling, so every token rotation polls the entire 0-127 address space looking for masters that aren't there — network performance craters. Keep field controllers in a contiguous low range and set max_master just above the highest used address.
ASHRAE 135 (BACnet) — MS/TP Physical Layer
BACnet MS/TP requires a daisy-chain (bus) topology, not star topology. Star wiring creates signal reflections and communication failures. Each device must connect in series on the bus.
ASHRAE 135 (BACnet) — Object Types
Connecting a 0-10VDC analog output signal to a binary (digital) input terminal will not control the device properly. Binary inputs only read on/off states. Analog signals must connect to analog input terminals for proportional control.
ASHRAE 135-2016 / Crestline BAS Specification
Crestline specifications require all building automation systems to comply with ASHRAE Standard 135-2016 (BACnet). Proprietary, closed-protocol systems lock the owner into a single vendor and prevent competitive service and integration. Open-protocol BACnet is mandatory for all new installations.
ASHRAE 15
ASHRAE 15 requires a refrigerating machinery room to be separated from the rest of the building with tight-fitting, self-closing doors. The room is designed to contain a refrigerant release and exhaust it to the outdoors. Wedging the doors open defeats the containment and lets a release migrate into occupied space.
ASHRAE 15 §9.9 (Pressure-Limiting Devices)
Head pressure of 165 psig is 40 psig above design, directly caused by the reversed condenser water piping. Watch the authority: the high-pressure cutout setting comes from ASHRAE 15 §9.9 and is referenced to the vessel design pressure, NOT to a universal number — there is no "trips at 175 psig" rule in any standard, and AHRI 550/590 is a performance-rating standard containing no safety-control provisions at all. Running this far above design costs compressor power and pushes the machine toward a nuisance high-pressure trip.
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.