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Reliable alternative to this fan?

KGisME

Mechanical
Feb 7, 2024
18
Hi all. I’m looking to replace this furnace draft inducer fan we use for cooling a very expensive avionics computer in a stationary simulator as detailed here. FASCO’s datasheets have no info on CFM or SP that I can find, so it's difficult to know what CFM & SP to look for in a replacement fan. I am about to test what pressure the fan is producing in our duct here this afternoon, so I can at least give you that later this afternoon. These often run for 12+ hours straight, 5 days a week. So as you can see, something reliable as possible (We are installing this new protection system that will better protect the computer in the event of a fan failure as detailed in the post linked above, so we don't need to get crazy with aerospace or NASA-level mission critical fans)

Unlike whoever originally designed the fixture this all goes on, I’ll mount the new fan either shaft vertical or shaft horizontal, whatever makes more sense for the fan I end up with.

We’d also like it as quiet as possible. I'm trying to decide if I might want an ECM (or other speed controllable motor via a 4-20mA or 0-10V signal). We might want to just keep it as cool as our chosen fan is able to by running it full speed at all times, but on the other hand, reducing noise in this space is always preferred if all else is equal.

Cost is actually not a big concern but the real challenge here is that they ideally went one made in the US (Stupid, I know, but some of our contracts require it).

The fans that come to mind for me here are the small inline duct fans from the likes of Fantech, Soler & Palau, and Continental(CFM). Continental being the only of those based in NA (but I still have to check with Continental on where they’re manufactured), does anyone know how reliable any of their small fans of this general size https://continentalfan.com/wp-conte..._Duct_Fans_Wholesale_Ventilation_Products.pdf are? It looks like their AXS EC and Elicent AXC series are made for continuous duty.

I'm open to large PC fans too (probably the centrifugal blower-style ones rather than axial, but we'll see once I test the static pressure of the current fan here in a couple hours)

Anyone have other ideas? Or know of other US-made fans in this general CFM & SP range?
 
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Oooo these may fit the bill as well. https://www.greenheck.com/products/air-movement/fans/ceiling-exhaust-fans
I used more Greenheck fans in my previous life in custom industrial HVAC equipment, but I didn't realize they even made this type of little bathroom fart fan. Says they're designed for continuous duty and supposedly very quiet.
 
You are trying to replace an inline fan that connects to duct on inlet and outlet. How will this fan replace the existing one?
 
If you know the differential pressure as you indicate you will take measurements, and you know the horsepower, then you can select a replacement fan based on this information since the only other unknown is the flowrate.

The attached is a greenheck catalogue for industrial blower. If you know the motor nameplate horsepower then you can select a fan with a brake horsepower about 80% to 90% of your actual existing nameplate motor horsepower at the measured differential pressure per the tables in the catalogue. This assume that the efficiency of the greenheck fans are about same as the efficiency of the existing fan. In this case the selected fan should have approximately the same flowrate as your existing fan.
 

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You are trying to replace an inline fan that connects to duct on inlet and outlet. How will this fan replace the existing one?
The existing fan is this furnace draft inducer https://www.regalrexnord.com/produc...draft-inducer-blower-115-volts-flange-no-a088 , which is only connected to our system at the fan outlet. The fan inlet draws from the ambient space.

Will it cause problems to connect only to the outlet of an inline fan and leave the inlet to just draw from the surrounding space? (with some type of screen/filter to prevent debris from being ingested, of course)
 
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Ok finally was able to test it yesterday and found that the SP is 1.3" W.C.

The existing fan is 1/30 HP, although Fasco has since changed the motor on that model, and the new ones they sell now have a 1/25 HP motor instead. I know it's a shaded pole motor. Now, how to spec a suitable replacement...
 
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