Residential hood with makeup air

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James L

James L

Senior Member
Location
Kansas Cty, Mo, USA
Occupation
Electrician
I've been asked to install, vent, and wire a residential hood that's 1,200 cfm. I know I need a makeup air, too.

I've never wired a redidential makeup air unit.
I have no specs or cut sheet for the hood, so I'm curious what's typical for connecting the MUA to the hood. Is it a particular hood type, with auxiliary power out for MUA?

Maybe similar to a downdraft vent that has remote blower getting powered from main unit?
 
I should add:

This is a rough in on a gutted kitchen. So at this point it's just ducting and wiring. The contractor has not picked out a hood yet, but homeowner wants 1,000+ cfm so I know it needs MUA
 
James L said:
I should add:

This is a rough in on a gutted kitchen. So at this point it's just ducting and wiring. The contractor has not picked out a hood yet, but homeowner wants 1,000+ cfm so I know it needs MUA
Click to expand...
I don't know, most commercial units is just a hood - motor is in separate unit on the outside of the building/on the roof, and you will have a control (possibly just a toggle switch) somewhere inside, in that case just power the MUA from same switch either directly or via a relay if separate circuit is needed.
 
Usually the hvac guy handles the low voltage control from the hood to the blower located remotely or above the hood.
 
kwired said:
I don't know, most commercial units is just a hood - motor is in separate unit on the outside of the building/on the roof, and you will have a control (possibly just a toggle switch) somewhere inside, in that case just power the MUA from same switch either directly or via a relay if separate circuit is needed.
Click to expand...
I'm just guessing since it's a residential hood, it probably has the controls on the unit But maybe not
 
James L said:
I'm just guessing since it's a residential hood, it probably has the controls on the unit But maybe not
Click to expand...
I've never seen a resi hood that gives you anything to make this easy. Make up air for resi hoods has been in the ICC for a long time yet the manufacturers act like they have never heard of it.
 
James L said:
I'm just guessing since it's a residential hood, it probably has the controls on the unit But maybe not
Click to expand...
I don't think I ever seen a residential hood with that much CFM. Would think if it were that much might possibly be more like you would find in commercial application. Unless you regularly cooking for 10+ people, who needs that much of a cooking fan in a house?
 
We run into it on almost all of the large homes that we do. There is a air flow switch that is low voltage that goes back to the furnace blower (I have seen that) or to a separate fan and relay
 
texie said:
When I have had make air on resi hoods I have used a RIB current switch located in the hood to trigger the make up air fan. That way you don't modify any factory wiring.
Click to expand...
I just noticed this reply. Thanks

Something like this one?

CrocSee Miniature Current Switch, CS-TS0, Normally Open Amp Sensor Monitoring Relay, AC 1-50A Detectable - - Amazon.com

CrocSee Miniature Current Switch, CS-TS0, Normally Open Amp Sensor Monitoring Relay, AC 1-50A Detectable - - Amazon.com
smile.amazon.com
 
kwired said:
I don't think I ever seen a residential hood with that much CFM. Would think if it were that much might possibly be more like you would find in commercial application. Unless you regularly cooking for 10+ people, who needs that much of a cooking fan in a house?
Click to expand...
I've had issue with a simple stock residential hood, the home was very well sealed with insulation and whenever exhaust hood was run or even the dryer it would create enough vacuum to snuff out the pilot on the water heater and the oil furnace would fault out because of it. Had to install a simple actuated baffle that would open to allow for makeup air when heat was running, it worked from the heating unit not the exhaust hood. I know not quite the same thing, but goes to show the residential hood can create enough vacuum to be an issue.
 
James L said:
I've been asked to install, vent, and wire a residential hood that's 1,200 cfm. I know I need a makeup air, too.

I've never wired a redidential makeup air unit.
I have no specs or cut sheet for the hood, so I'm curious what's typical for connecting the MUA to the hood. Is it a particular hood type, with auxiliary power out for MUA?

Maybe similar to a downdraft vent that has remote blower getting powered from main unit?
Click to expand...
I'd tell them you can not pre-wire or vent for an unknown system, and they need to choose one now.
 
Fred B said:
I've had issue with a simple stock residential hood, the home was very well sealed with insulation and whenever exhaust hood was run or even the dryer it would create enough vacuum to snuff out the pilot on the water heater and the oil furnace would fault out because of it. Had to install a simple actuated baffle that would open to allow for makeup air when heat was running, it worked from the heating unit not the exhaust hood. I know not quite the same thing, but goes to show the residential hood can create enough vacuum to be an issue.
Click to expand...
Commercial building usually bring in outside air to create a positive internal pressure.

A heat-recovery device would be the best way to do that in a home, or at least a vent to the return.
 
kwired said:
I don't think I ever seen a residential hood with that much CFM. Would think if it were that much might possibly be more like you would find in commercial application. Unless you regularly cooking for 10+ people, who needs that much of a cooking fan in a house?
Click to expand...

It depends on the BTUs of the gas cooking appliances. It's common today for kitchens to have at least 6 burner ranges, double ovens, griddle, grill, etc. A 1000+ Cfm vent hood with makeup air is not at all unusual. This should be designed by an HVAC guy with credentials in air balancing and ventillation, not the EC or GC.

-Hal
 
LarryFine said:
I'd tell them you can not pre-wire or vent for an unknown system, and they need to choose one now.
Click to expand...

Yeh, that’s the answer. You could try to wire for all the variables, but it’s cheaper if they’ll just make a decision now.


Sent from my iPad using Tapatalk
 
I got some model numbers for hood and makeup air, which is just a damper - not a motor.

Hood:
www.appliancesconnection.com

Trade-Wind 724812 $3,039.00

7248-12 48" Barbecue Grill Hoods with 1200 CFM, Stainless Steel Baffle Filters, Halogen Lighting, 3 Speed Control, in Stainless Steel
www.appliancesconnection.com www.appliancesconnection.com

MUA:

Amazon.com: Broan MD10TU Motorized Universal Make-Up Air Damper with Pressure Sensor Kit, 10": Home & Kitchen

Buy Broan MD10TU Motorized Universal Make-Up Air Damper with Pressure Sensor Kit, 10": Heating, Cooling & Air Quality - Amazon.com ✓ FREE DELIVERY possible on eligible purchases
smile.amazon.com

Looks like a 24v damper with air pressure switch. Broan has a calculator/recommendation page to match MUA with hood CFM.

This is likely the setup @Dennis Alwon had in mind. So looks to be pretty straightforward. I'll see what the transformer looks like, and determine where to place it and power it.
 
texie said:
When I have had make air on resi hoods I have used a RIB current switch located in the hood to trigger the make up air fan. That way you don't modify any factory wiring.
Click to expand...
onna deez??>>>
www.supplyhouse.com

RIBXGF - Functional Devices RIBXGF - Enclosed Self Powered Split Core, Fixed Current Sensor, .35-150 Amp, Wire Leads

Functional Devices RIBXGF - Enclosed Self Powered Split Core, Fixed Current Sensor, .35-150 Amp, Wire Leads - <b>Specifications:</b><br> <ul><li>Operating Temperature: -30 to 140° F <li>Humidity Range: 5 to 95% (noncondensing) <li>Max Sense Voltage: 600 Vac <li>Approvals: UL Listed, UL916...
www.supplyhouse.com www.supplyhouse.com

~RJ~
 
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