Mounting a minisplit condenser on standard concrete blocks
Here in central Arizona, I don’t have to worry about much snow, but we do get torrential rains (“the monsoons”) and various creatures who like to urinate on or find a way into anything new, so it seems a good idea to elevate the outdoor condenser units for my two minisplits perhaps 16 or 24 inches above ground level. My online searches for the various ways people accomplish this have turned up mostly steel stands, of which the most affordable are around $70-90 but apparently vulnerable to eventual rust. I’ve also seen a few condensers raised just 4 inches on solid, 4x8x16 concrete blocks, but I haven’t seen any photos or descriptions of anyone using standard 8x8x16 concrete blocks, which would be least expensive per height and, with some mortar, quite durable. They could be capped with 2-inch solid blocks. I get that concrete blocks might cause snow to accumulate in a way that steel legs wouldn’t, but for a non-snow installation, would blocks make sense?
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If there's something wrong with using standard 8x8x16 concrete blocks, I can't think of what it would be, and if there isn't, I'm very surprised I can't find a single photo or description of anyone using them.
Hi etting,
I'll give you another bump. I'll also ask Jon Harrod your question. He might have some thoughts to share. Read his recent post on Heat Pump Mounting Systems--it might give you another idea.
Thank you, Kiley!
This approach should work well for small single-fan outdoor units, as long as they're on a stable substrate like concrete or tamped gravel. Keep the blocks as far to the sides as possible so that the defrost water can drain freely from the bottom of the unit. For larger dual fan units. I'd be concerned that 16" blocks aren't big enough to provide good front-to-back stability.
Thank you, Jon!
Yes this is fine. Drain hole is approx centered in the housing under the outdoor coil, don’t push the blocks too far out. The feet should be about centered on the block for weight distribution. More importantly, tapcon the feet to the block so the unit doesn’t “walk” over time and put undue stress on the connection and disrupt the joint. That can cause a leak and lead to a whole set of other problems.
Thank you, Mitsuman!