# Detail or Installation Mismatch in Division 23 Heating, Ventilating, and Air Conditioning (HVAC) submittals

> Source: https://deviationcheck.com/divisions/23-hvac/detail-installation-mismatch/

The submitted detail, dimension, anchorage, or installation method differs from what the spec or drawings require.

## What to look for in Division 23 Heating, Ventilating, and Air Conditioning (HVAC)

- **Duct gauge** lighter than spec (e.g., 22ga where spec requires 20ga for high-pressure duct)
- **Duct connection type** (flanged vs slip-and-drive vs welded)
- **Pipe material** mismatch (Type L vs Type M copper, Schedule 40 vs 80 steel)
- **Pipe joining method** (brazed vs soldered, press-fit vs threaded vs welded)
- **Hanger/support spacing** exceeds spec or SMACNA maximums
- **Insulation type** (closed-cell vs fiberglass, vapor barrier presence)
- **Drain piping** size or material differs
- **Vibration isolation** type or deflection rating differs from schedule
- **Refrigerant line sizing** differs from manufacturer requirements
- **Controls wiring** type or protocol differs (BACnet vs Modbus vs proprietary)
- **Access door** size or location differs from spec requirements
- **Seismic bracing** method or spacing differs

## Severity

Default grade: Fix and Resubmit. Escalates to Blocker when the difference affects a fire-rated, seismic, or structural assembly.