VAV Boxes & Terminal Unit Replacement
VAV and fan-powered box replacement, reheat coil and controller retrofits, and rebalancing that fixes zone complaints for good.
Most "the AC doesn't work in my office" tickets are terminal-level problems: a failed actuator, a plugged reheat coil, a pneumatic controller nobody can calibrate, a flow sensor reading nonsense, or a box that was never balanced after a tenant improvement. CMI replaces and retrofits VAV boxes, fan-powered boxes, dual-duct boxes, induction units and reheat coils across office, healthcare and laboratory buildings.
Retrofits are where the value is. Converting pneumatic terminal controls to DDC gives you occupancy scheduling, real airflow feedback, trending and fault detection — and it usually eliminates a compressed-air system nobody wants to maintain. We replace controllers, actuators, flow sensors and thermostats, program the sequences, and rebalance each zone to the design airflow.
Work happens above occupied ceilings, so it happens on your terms: night and weekend shifts, dust containment, ceiling tile protection, and a zone-by-zone punch list your tenants can see progress on. Every box is documented — tag, location, size, min/max CFM, controller address and balance reading.
Scope & capabilities
- VAV, fan-powered, dual-duct, series/parallel and induction terminal unit replacement
- Pneumatic-to-DDC terminal control conversions
- Zone rebalancing with min/max CFM reset and documented readings
- Above-ceiling work under night/weekend and containment protocols
- Hot water and electric reheat coil replacement, valve and actuator renewal
- Controller, damper actuator, airflow sensor and room sensor replacement
- Duct modifications for tenant improvements and re-zoning
- Full box schedule and as-built documentation with controller addressing
The technical envelope
- Box sizes
- 4" – 24" inlet, single and dual duct
- Control platforms
- BACnet, LonWorks, Modbus, legacy pneumatic conversion
- Work windows
- Nights, weekends, occupied-space containment
- Deliverables
- Box schedule, balance report, controller point list
- Typical program
- 20 – 500+ boxes per phased project
Facility types
VAV Boxes & Terminal Units — straight answers
- Can hot and cold complaints be fixed without replacing boxes?
- Often, yes. We diagnose first: actuator stroke, flow sensor calibration, reheat valve position, duct static, min/max settings and the AHU sequence. Replacement is recommended when a box's controls are obsolete or the mechanical components are worn beyond calibration.
- Is converting pneumatic controls to DDC worth the cost?
- In most buildings it pays back through scheduling, correct minimum airflows and eliminating compressed-air maintenance — plus you gain trending, so the next complaint is diagnosed from data instead of a ladder.
- Do you work after hours in occupied floors?
- Standard practice for terminal work. Night and weekend shifts, protected floors and furniture, dust containment above the ceiling, and everything closed up before the tenants return.
Get a number you can budget against
We walk the plant before we price it. You get equipment condition, options, phasing and a schedule — not a guess with a contingency wrapped around it.