Manufacturers' representative for OEMs since 1983

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Air coils · Heat exchangers

Commercial HVAC Coils for OEMs: Evaporator, Condenser and Hot Water

The Back Bay Associates is a manufacturer's representative that has connected OEMs with commercial HVAC coil manufacturers since 1983. Our principals build custom evaporator, condenser, and hot-water coils in copper-tube, aluminum-fin construction for HVACR and Food Service Equipment builders.

JKReviewed by Jeff Ketterer, CEO/Principal, The Back Bay Associates

Heat-transfer coil
Built to your print
Copper tube · Aluminum fin · Custom circuiting

Coils decide how much heat your unit actually moves. Get the circuiting wrong, and you'll find out in the test lab, or worse, in warranty claims. We put your print in front of the coil manufacturer best set up to build it.

We work with OEMs that design and build equipment. For a single replacement coil, an HVAC distributor is the right call.

01

Custom Evaporator Coils

Our principals build custom DX evaporator coils with a wide range of distributors and TXVs, so refrigerant pressure and temperature drop where they should. Circuiting is flexible. Face-split designs divide the coil into top and bottom circuits, and intertwined designs interlace the circuits across the full face. Which one fits depends on how your unit stages capacity.

Circuiting
Circuit ACircuit B

Face-split: top and bottom halves run as separate circuits, so the unit can stage capacity by shutting one down.

HVACR
02

Custom Condenser Coils

A condenser coil releases the heat your system picked up at the evaporator. Our principals offer a wide range of coil patterns and tubing materials, including condenser coils for commercial condensing units, sized to your footprint, airflow, and load.

FootprintAirflowLoad
03

Hot Water Coils

Hot water coils are tube-fin heat exchangers: rows of tubes running through formed fin sheets, bonded by mechanical tube expansion. That expansion presses each tube tight against the fin collars, and that contact is where heat transfer happens.

Formed fin sheetsMechanically expanded tubes
Refrigerant transition

Designing Coils for A2L Refrigerants

If you're redesigning a unit for lower-GWP A2L refrigerants such as R-454B or R-32, the coil usually changes too. Charge limits push designers toward lower internal volume, which can mean smaller tube diameters, different circuiting, or fewer rows. Bring the coil manufacturer in before the cabinet is frozen. It's a cheaper conversation then. On most redesigns, the coil, blower wheel and ECM motor usually change together.

R-454BR-32
↘Lower internal volume ↘Smaller tube diameters ↺Different circuiting or fewer rows

Replacement HVAC Coils for OEM Service Programs

For OEMs supporting units already in the field, our principals build replacement coils that match the original's dimensions and performance, and they ship quickly.

Before you send it

What to Include in Your Coil RFQ

The more of this you send, the faster and more accurate the quote. Tick off what you have ready.


Request a coil quote
Project story

Eliminating Moisture Carryover on a Large-Tonnage A/C Launch

An HVAC OEM was launching a newly designed, very large tonnage A/C unit to win substantial new business from a key customer, but the first expedited evaporator coils were shedding water droplets into the airstream on a tight timeline. Back Bay brought our air coil manufacturer's engineering and quality team on-site overnight. Working side by side with the OEM, they adjusted the evaporator coil height, repositioned the blower assemblies, specified a better-matched TXV, and fast-tracked redesigned samples. The OEM secured the program and, thanks to the performance upgrade, was awarded an even larger share of the business, which we continue to support today.

Coil FAQ

An evaporator coil absorbs heat from the air as refrigerant evaporates inside it, cooling the space. A condenser coil releases that heat to the outdoors as the refrigerant condenses back into a liquid.

It’s a coil whose face is divided into separate refrigerant circuits, usually into top and bottom sections. A unit can then stage capacity or run independent circuits through one coil.

It’s the number of fins in each inch of coil length. More fins increase surface area and capacity, but they also increase air-side pressure drop and collect more dirt.

Yes. Most coils we source are built to the OEM’s specifications.

No. We work with OEMs. For a single replacement, contact an HVAC distributor.

Have a coil print on your desk?

Send it over. We'll put it in front of the right coil manufacturer.

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