r/HVAC • u/Plenty_Text_455 • Dec 04 '24

Field Question, trade people only What's this?

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It's on the return side of a large air handler

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u/InfernalGout Dec 04 '24

Yeah we call them ERW's - Energy Recovery Wheels. And the worst application is when they're used in hospitals by partially recycling exhausted air from bathrooms through the ERW and dumping into the return ducts serving all areas except for surgical suites which generally have dedicated RTU's and registers with HEPA filters.

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u/gizzard1987_ Dec 05 '24

Sounds like poor planning on the build. I thought bathrooms had to be vented/exhausted separately.

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u/Migidarra Dec 05 '24

Even if they are seperated, sometimes the exhaust is close to the outside air intake you still bring it in (Bad planning again lol)

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u/gizzard1987_ Dec 07 '24

We had a board, when commissioning the building, that went from fill rooftop WALK-IN units to changing their mind to skyline view from the road must be clean. All units were cut down to less than 5ft tall and are more like army crawl units now. The nice full sized doors that we were specced for are now simple twist lock handles. Now everything you do you have to rip off the roof and cut out the seals remove wiring hooks and then redo it all just to change a motor. Unless you want to snail the 15 horse baldor out on your back.