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  • Pete McGrath

NICE SWEATER: An Insider's Glossary of HVAC Trade Slang

During my four-plus decades in the trade, I've picked up more than my share of HVAC industry slang. Here are a few of my favorites:

tin can: a hermetically sealed A/C or refrigeration compressor

The unit is blowing warm air because the tin can is shot.


quick pick: removal by crane or forklift of an old rooftop unit, immediately followed by replacement with a new unit. Also known as one up/one down.

The quick pick is scheduled for Thursday morning.


screamer: 1. an exhaust fan running at a very high speed; 2. a fast-paced project

No time to talk, we’ve got a screamer.

dump box: variable air volume (VAV) bypass terminal

Check the airflow on those dump boxes.


sweater: a large amount of dirt and pollen caked on an air-cooled condenser

From the looks of that sweater, it's no wonder the A/C isn't working.


CRAC split: split computer room air conditioning unit that utilizes a condenser

Please fix that CRAC split quickly.


Mit split: Mitsubishi ductless mini-split HVAC system

We quoted them on a new Mit split.

knockdown reg: a natural gas or steam regulator

The problem could be a bad knockdown reg with those pressure fluctuations.


drive: variable frequency drive (VFD)

The service technician drove to the facility to check the drive.


stick: the straight boom of a crane

The unit is hooked up and the stick is ready to go.

pop four corners: the act of prying the corners of a rooftop HVAC unit from its curb to ensure it lifts away freely during its removal

Pop those four corners, the crane will be here any minute.

"cut us loose": a request to a client for project approval

Cut us loose so we can get going on this job ASAP.


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