Roof penetration for rooftop units

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Brownetown

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Electrican
I have a RTU and kitchen hood exhaust that I have to get to on a flat roof. They’re about 10’ apart on the roof. I was wondering what you guys would do. I’m thinking ether making a 1” penetration next to each unit near the disconnect or what about 1-2” penetration on the middle of the 2 and take my conduits threw and run on the roof. Ether way a roofer contractor will
Be installing a watches hat or what ever they recommend. My feet for penetrating near units messing up the flashing they used for the curbs
 
The ones I have worked on in the past I ran through the curb. Problem is how these sit conduit needed to be run while they sat the units on the curb. We didn’t know what day they were setting them. Anyways. 6” away from unit should be clear from any flashing that was installed from the curb
 
Brownetown said:
The ones I have worked on in the past I ran through the curb. Problem is how these sit conduit needed to be run while they sat the units on the curb. We didn’t know what day they were setting them. Anyways. 6” away from unit should be clear from any flashing that was installed from the curb
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What you should be doing is finding out who the roofer is from the guys that are setting the units and curbs, tell them how many roof booties you need for your penetrations or if you need pitch (tar) boxes for asphalt built up roofs. Have the contractor setting the equipment get the required booties or boxes from their roofer to match the material that roof is made of.

Then you place the provided booties over your conduits when your installing them. Place the booties or pitch boxes over your conduits as your installing them. Make your penetration hole just big enough for your conduit, then it can be temporarily sealed with roofing caulk. Leave the boots raised up on the conduits for the roofer, then have the HVAC contractor call the roofer to come and provide the final seal up. This way you wont void any roof warranty or be responsible for any leaks now or in the future.

Going through the roof underneath the curb and equipment is the best way and avoids most penetrations that need to be sealed by the roofer. But to do that you will need long pilot bits to mark your penetration location, and some hole saw extensions to reach from the curb height to the roof surface.

The same type method can normally used on the exhaust fan curb, but most exhaust fans need a flex whip installed above the curb in order to hinge the fan open for cleaning. Locate your required disconnect on the side of the fan curb.
 
this depends on the RTU manufacturer. Some are great, like Captive Air, with KOs plate inside the unit directly under their disco. some suck like York that are impossible to feed through the unit but must go through the roof or curb wall outside the unit. I would find the model numbers of the units to determine how... . Kitchen hood exhaust is usually from outside the unit through the roof or curb wall and should come from the correct corner so it can pivot/hinge properly but you can cheat. Some exhausts can go through the conduit tube inside the mushroom but they are usually non kitchen type.

I'd penetrate near the units rather than 5' away with common hole
 
That’s what I was thinking. I was able to penetrate the RTU. I have to use an extension drill a pilot hole then drill from underneath the decking. The exhaust I haven’t done yet but the way they wrapped there seal on there duct leading threw the roof completely sealed around any spackling between duct and curb going up. So I will have to penetrate roof. But I already had roofing contractor on stand by. So I won’t drill until they get on site early next week. Thank you for all the feed back.
 
You may need two penetrations for the exhaust fan. Most of the systems I installed in the last couple of years required line voltage and a PWM speed control circuit. Space those penetrations a foot apart to leave room for the boots on each conduit.


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