Trace each unitary HVAC unit from the schedule into its equipment category, efficiency basis, refrigerant safety classification, and controls-protocol interface, then compare economizer, heating source, and roof or wall support for the same unit before treating a schedule entry as complete.
Assemble the review package
Gather the mechanical equipment schedule, the roof or wall-mounting detail for each unit, the building’s designated seasonal wet-bulb and design-temperature data, the direct-digital-control system documentation, and the issued decentralized unitary HVAC equipment specification. This guide covers packaged terminal units, room units, self-contained units, split systems, and air-source unitary heat pumps; variable refrigerant flow systems are excluded from this section and covered elsewhere. Review one unit completely before assuming a similar tag elsewhere carries the same refrigerant classification and controls protocol.
WBDG publishes UFGS 23 81 00: Decentralized Unitary HVAC Equipment as a public guide-specification reference (accessed September 24, 2026). Use your project’s issued specification and amendments for the actual comparison; the guide specification does not automatically govern your project. The checklist below is an original suggested review workflow, not a reproduction of the UFGS requirements.
Eight checks to run against the issued set
Use one record per location or system. The CSV contains the same eight prompts plus fields for source revisions, observed evidence, the review owner, the decision, and closure references.
| Check | Sources to compare | Question to resolve |
|---|---|---|
| Equipment category assignment | Schedule unit type + specified equipment category (packaged terminal, room, self-contained, split-system, unitary heat pump) | Does the scheduled unit resolve to one of the specified equipment categories, and does its mounting condition (through-wall, roof-mounted, split with remote condenser) match the drawings? |
| Efficiency basis | Schedule SEER, HSPF, EER, or COP value + specified minimum efficiency and ASHRAE 90.1 basis | Does the scheduled efficiency value use the same metric and full-load or part-load basis as the specification’s minimum, rather than comparing unlike values? |
| Refrigerant safety classification | Unit location and refrigerant quantity + ASHRAE 15 and 34 system application requirements | Where refrigerant-containing components are located indoors, do the documents identify the occupancy classification, system probability, and any resulting mechanical-room or refrigerant-detection requirement? |
| Economizer requirement | Unit capacity and location + specified fully modulating economizer option | Where the specification requires an economizer at a given capacity or climate condition, does the schedule and control sequence show it provided for the qualifying units? |
| Heating source coordination | Schedule heating-coil type + specified electric, gas-fired, hot-water, or steam option | Does the specified heating source match the building’s available fuel or hydronic source at that unit, and is a gas-fired section excluded where the unit serves an electronic-data-processing space? |
| Controls protocol interface | Specified BACnet or LonWorks tailoring option + the building’s existing direct-digital-control system | Does the unit’s specified control-system interface protocol match the protocol used by the direct-digital-control system already serving the building? |
| Roof curb and structural support | Roof curb detail + structural framing plan at the unit location | Can the specified roof curb height and unit weight be traced into the structural support shown at that location, including any wind or seismic bracing? |
| Corrosion protection | Project environmental severity or coastal exposure + specified coil coating and cabinet finish | Where the project is in a corrosive or coastal environment, does the schedule call out the specified coil coating and cabinet corrosion protection for the exposed units? |
Worked example: a split system without a matching controls protocol
Illustrative example: a split-system heat pump is scheduled for a building whose existing direct-digital-control system is documented as LonWorks, but the unit’s specified controls tailoring option shows both BACnet and LonWorks selected at once. Neither the schedule nor the controls submittal identifies which protocol the new unit’s interface actually uses.
Confirm the building’s existing control protocol from the direct-digital-control documentation, correct the tailoring selection to the single matching protocol, and recheck the communication-network requirement between any physically separate indoor and outdoor sections before closing the item.
Avoid a false conflict
A schedule that lists an efficiency value or a refrigerant type does not by itself confirm the safety classification, economizer requirement, or controls protocol were carried through; each depends on the unit’s location, capacity, and the specific building system it ties into, not on the equipment tag alone.
When requirements disagree, follow the project’s document-control and clarification process. Do not assume that drawings always override specifications, or the reverse. Identify the exact sources and request an authorized decision.
Close the issue across the affected documents
Record the location or tag, drawing and specification references, issue dates, observed difference, and the decision needed. Assign an owner and keep the item open until the response identifies the governing requirement. Check the revised drawings and specification references together; a response email alone may leave the issued package inconsistent.
For the overall process, use the guide to drawing and specification conflicts. Mark an inapplicable checklist row with a reason, and distinguish a verified correction from a question that still needs design information.
Where Groundbook fits
Groundbook’s drawing and specification review helps investigate potential disagreements in the documents you supply. Include the relevant specification sections and drawing references, then verify the cited evidence with the responsible reviewers before acting on a finding.