Field-Ready · Lesson G36
ASHRAE Guideline 36
One standard set of sequences for VAV systems. Trim and Respond logic, reset strategies, and fault detection built in from the start.
What Guideline 36 Is
ASHRAE Guideline 36 is a document. Its full title is "High-Performance Sequences of Operation for HVAC Systems." It gives one standard set of control sequences for common HVAC systems. It covers multiple-zone VAV air handlers, VAV terminal units, and some central plant equipment.
Before Guideline 36, sequences were not standard. Each controls contractor wrote its own logic for the same type of system. One AHU sequence used one reset method. Another AHU, built the same way, used a different method. Point names differed. Setpoints differed. A technician who learned one contractor's sequence often had to relearn the next job from scratch.
Guideline 36 gives a single reference sequence for each system type. An engineer writes the project specification around it. A programmer builds the logic from it. A technician who knows Guideline 36 can walk onto a new job and already understand most of the sequence, before reading a single line of project-specific code.
Why it exists
- ·It saves energy. The sequences reset setpoints toward the least energy use that still meets the load.
- ·It gives stable control. The reset logic moves setpoints slowly. It does not hunt or overshoot.
- ·It reduces engineering and commissioning time. A programmer starts from a proven template instead of a blank page.
- ·It builds in fault detection and diagnostics. Each sequence includes rules that catch a failing sensor, a stuck damper, or a valve that leaks by.
Guideline 36 is not a law. No code requires it by name. But many owners, engineers, and utility rebate programs now specify it directly, because it gives predictable, documented performance. You will see it more often every year.