[Climate Controlled Environment] - Replacing EG4 18kPV Fans

[wpns]

You definitely need to allow make up air as low in the closet as possible, though if you put standard vents in the door and the fans ramp up, you may hear them.

 

[SurferJon]

They're so quiet the doors can be wide open and I'd only hear them right there. :D

We might be getting out of electrical territory here, but would air going into the closet and then into the attic vents affect the A/C or furnace in any way? Or the temp of the house?

 

[wpns]

In that case, put a vent low down on the door, as large as practical.

 

[xico0xff]

@SurferJon - awesome!! Seriously, the quieter fans make all the difference in the world.

For what it's worth, even if you had the louder fans, the temperature inside the closet would still be rising the same. The fans are only moving thermal energy from the inverter out into the ambient air. You still need to move that thermal energy in the air outside of the closet (generally you'll have parasitic leaks through the walls, air ingress and movement through insulation etc.

But yes, now that it's more quiet, you can put some air registers or vents to allow air to cycle through. A simple solution to test things would be to just have the utility closet door open a bit and put a fan on the floor blowing outward, that will get air movement into the closet - then you can decide if you want to add air registers for natural convective movement

 

[wpns]

have the utility closet door open a bit and put a fan on the floor blowing outward

Agree, except the fan on the floor should be blowing inward to assist natural convection

 

[SurferJon]

I cut a 12x4 floor vent to the crawl space beneath the house. The other day it was 95*F outside, but the crawl space stayed 72*.

I also installed a 4" ceiling vent connected to a 200 CFM attic exhaust fan in the attic, while keeping the existing ceiling and low wall vents since I think I need them for furnace combustion.

Unfortunately, the weather dropped back to 70°F right after, so I haven't been able to test how well everything works yet.

I'm still considering whether to enlarge the floor vent, upgrade to a 6" attic duct, and/or switch to a 400 CFM fan.

(Excuse the mess in the photos, not done yet.)

 

[wpns]

I cut a 12x4 floor vent to the crawl space beneath the house. The other day it was 95*F outside, but the crawl space stayed 72*.

I also installed a 4" ceiling vent connected to a 200 CFM attic exhaust fan in the attic, while keeping the existing ceiling and low wall vents since I think I need them for furnace combustion.

Unfortunately, the weather dropped back to 70°F right after, so I haven't been able to test how well everything works yet.

I'm still considering whether to enlarge the floor vent, upgrade to a 6" attic duct, and/or switch to a 400 CFM fan.

(Excuse the mess in the photos, not done yet.)

View attachment 298227View attachment 298228View attachment 298229

Make sure you don’t mess with the pressure balance required to allow the furnace to work properly.

 

[SurferJon]

What pressure balance?

 

[Zapper77]

What pressure balance?

And any vapor barrier

 

[apj]

@xico0xff do you have the model number of the original fans? I'd like to know what CFM they were spec'ed for.

 

[TacoMeat]

I've done similar modifications/testing with lower RPM fans and additional heatsinks in the Lab. If you want to PM me, I can give you a few recommendations if you run in to overheating issues.

I would LOVE to hear some of these recommendations. PM if possible

 

[xico0xff]

@xico0xff do you have the model number of the original fans? I'd like to know what CFM they were spec'ed for.

Oops, sorry for the late reply. I believe they are NMB 08025VE-12P-CUD-6 - harsh/wet environment fans rated for 73CFM and IP68 rated, which makes sense since the unit is built to be mounted outdoors. Best bet is to use the recorded temperatures available in the EG4 control center -> data history to track your temps and use that as a baseline.