Bolt size & type for mounting condenser on concrete pad

[gamp945]

Maybe a dumb or simple question

I'm installing a mini-split for my small workshop. What size and type of concrete anchor do you all use for a mini-split condenser? The manufacturer's instructions don't say what to use.

I've googled and youtubed and have mostly come up empty, with this exception:

I've got two hesitations with the video's suggestions. First, a 3/8" x 3" anchor seems pretty big for my little 9K BTU condenser. Second, I don't think the blue tapcons are adequate for exposed outdoor use. What are your thoughts?

Thanks for reading

 

[theoldwizard1]

Personally, for non-structural, lightweight anchoring to concrete I use these



I get rid of the screws that come with these in favor of stainless. Cheap. Amazingly strong. You need a masonry bit to drill the holes.

Don't forget the vibration pads !

 

[gamp945]

I did a bit more searching tonight and came across an engineer's document produced for GREE (major manufacturer of mini splits) designed for the Miami-Dade hurricane code requirements. I reason that if the engineer's specs are good enough for Miami, they are good enough for anywhere else in the country.

For all of the mini split sizes in the document (from 18K to 42K BTU), the engineer specifies a 1/4" Tapcon with 1.75" of embedment (he also specifies hurricane straps for Miami). That anchor size is a lot smaller than the only other recommendation that I've seen thrown around as shown in the OP (3/8" x 3"). The engineer gives a lot of other information in the document if you are interested (edge distance, pad size, fender washer size, etc). I've attached the PDF.

 

[gamp945]

Don't forget the vibration pads !

I'm surprised that I don't see more people using these when I've watched installation videos on YouTube. I don't understand why? The Pioneer unit that I am installing came with vibration pads, but I'm going to swap them out for some more deluxe ones. Aside from vibration, these seem important to prevent the condenser's feet from rusting out by sitting on the concrete.

 

[theoldwizard1]

Aside from vibration, these seem important to prevent the condenser's feet from rusting out by sitting on the concrete.

Which is why I use stainless steel #12 screws with those Poly-Set anchors !

#12 is approximately 3/16"

 

[teknikfrog]

I feel like I heard somewhere that with (air) compressors you should not torque the bolts to avoid causing fatigue issues. Is that true? Same thing with AC compressors?

 

[gamp945]

That makes sense to me for both compressors and condenser units. I suppose just light compression - maybe 1/8" - of the vibration pads would be ideal?