Division 23 Heating, Ventilating, and Air Conditioning (HVAC)

Manufacturer or Product Substitution in Division 23 Heating, Ventilating, and Air Conditioning (HVAC) submittals

By Deviation Check Editorial Team. Last reviewed June 1, 2026.

Short answer

The submittal proposes a different manufacturer or product than the spec names, without an approved or-equal or substitution request. Default grade in Division 23 Heating, Ventilating, and Air Conditioning (HVAC): Blocker.

The submittal proposes a different manufacturer or product than the spec names, without an approved or-equal or substitution request. This guide covers how it shows up specifically in Division 23 Heating, Ventilating, and Air Conditioning (HVAC) submittals.

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

HVAC specs routinely name basis-of-design manufacturers (Trane, Carrier, Daikin, York/Johnson Controls, Lennox, McQuay) with model series. Submittals proposing alternate brands must provide "or equal" documentation. Look for:

  • Chiller, RTU, or AHU manufacturer/model substitutions
  • VAV box manufacturer changes (Titus, Price, Krueger, Nailor)
  • Controls manufacturer substitutions (Honeywell, Johnson Controls, Siemens, Distech)
  • Duct insulation or pipe insulation brand changes
  • Pump manufacturer substitutions (Bell & Gossett, Grundfos, Armstrong)

Common examples in Division 23 Heating, Ventilating, and Air Conditioning (HVAC) submittals

HVAC specs almost always name a basis-of-design manufacturer and model series, so a brand swap is the most common Division 23 deviation - and a "comparable" unit often changes capacity, footprint, electrical, and sound that ripple into other trades.

  • Chiller, rooftop unit, and air handler manufacturer and model (Trane, Carrier, Daikin, York/Johnson Controls, Lennox, McQuay) against the basis of design, with a signed or-equal request where the brand differs.
  • That the substitute's performance actually matches - cooling and heating capacity, efficiency (EER/IEER/COP), airflow, external static pressure, and sound power - not just the nominal tonnage.
  • VAV box manufacturer (Titus, Price, Krueger, Nailor) and that inlet sizes, minimum and maximum CFM, and sound data match the schedule.
  • Controls manufacturer (Honeywell, Johnson Controls, Siemens, Distech) against the spec, since a controls swap affects the BAS integration and the points list in Division 25.
  • Pump manufacturer (Bell & Gossett, Grundfos, Armstrong) and that the substitute holds the head, flow, and efficiency at the design point.
  • Duct and pipe insulation brand and that R-value, jacket, and flame and smoke rating still meet spec.
  • Electrical characteristics (MCA, MOCP, voltage and phase) of the substituted unit, since a change here forces a Division 26 coordination check.

A "comparable" rooftop unit that draws more amps or weighs more than the basis of design can break the electrical feeder and the structural curb, so check the substituted unit's full data, not just its tonnage.

How severe is it?

Default grade: Blocker. Drops to a Note if the submittal attaches an or-equal approval letter from the architect of record.

Deviation Check assigns a default per category and escalates or de-escalates based on the spec, always showing its reasoning. See the Division 23 severity rules.

What the PM should do

Treat this as a hold. Do not approve the submittal until the sub resolves it, either by providing the specified product and documentation or by routing an approved substitution or or-equal request. Return the relevant spec passage to the sub as a redline.

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Frequently asked questions

What counts as a manufacturer substitution in Division 23 Heating, Ventilating, and Air Conditioning (HVAC) submittals, and which equipment categories are most commonly flagged?

Any submittal that proposes a brand not named in the spec - without an attached or-equal approval letter from the architect of record - is a substitution. The most flagged categories are chillers, RTUs, and AHUs where the spec names Trane, Carrier, Daikin, York/Johnson Controls, Lennox, or McQuay; VAV boxes where Titus, Price, Krueger, or Nailor is specified; and controls where Honeywell, Johnson Controls, Siemens, or Distech is called out.

How does a subcontractor clear a manufacturer substitution flag on a Division 23 HVAC submittal before the PM accepts it?

The sub must attach an or-equal approval letter signed by the architect of record. That single document drops the deviation from Blocker to a Note. Without it, the submittal cannot advance - side-by-side cut sheets showing matching performance are supporting evidence but do not substitute for the letter. Pump substitutions (Bell and Gossett, Grundfos, Armstrong) and insulation brand changes follow the same clearance path.

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