Ultra Aire install
Just finishing up building a DelTec Passive Solar Ridgeline 1600 sq ft. in N. GA. Insulated Concrete Form Lower Level, and Spray Foam. 2×6 on 24in centers. Decided to go with Mini Splits. We’ve Got 3 wall units 2 in the basement and one in the great room with the 3 bedrooms on a ducted minispit system. We hired the closest Mitsubishi Diamond certified over our local guy we’ve used on other projects for their expertise in what we were planning.
The specs called for an ERV and an Ultra Air 98 shows up. They install it in a Alternative not recommended configuration. page 12 https://www.ultra-aire.com/pdf/Ultra-Aire_98H_Manual.pdf
HVAC return / supply and did not install a backdraft damper or a check damper and no motorized damper to the fresh air intake? It almost feels fellow the owner keeps sending appears to be feeling his way through the job. I surely shouldn’t be the one pointing out these things as it’s not my area of expertise. They’ve since installed the motorized fresh air damper and on a call the owner suggested we vent some of the 98 air to the outside through a bathroom vent. That doesn’t even show as a possibility on the install sheet? Wondering if this is common and what the best course of action is? Thanks
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I expect that you need to replace the incompetent.
The dedicated dehumidifier is a good idea for an energy efficient house in humid area.
Not sure how energy efficient it is to use the demudifier for ventillation, something stilll needs to condition the outside air, so there is a cost to that. Important part is there is something that can provide dedicated ventilation to the house, with mini-splits the fan typically runs all the time so you should get decent distribution.
I would make sure some of the air from the basement also gets to the 98 as this is what will need to get dehumidified the most.
As for you question, I don't see why you would want to exhaust any of the air from the 98. Once you bring the fresh air into the house, with this type of unbalanced ventilation, the air is exhausted through the leaks in the envelope.
In case the house is super tight, the dampers on the range hood and bathroom fan will open automatically if the house ever becomes pressurized by the 98.
P.S. Hope this is not a multi split configuration, even the smallest 4 zone multi split is way over sized for 1600sqft well insulated house.
It's an SEZ or Pancake in the attic for the 3 bedrooms and 2 baths. It has ducted supply and returns into each bedroom. https://www.greenbuildingadvisor.com/question/mitsubishi-minisplits-horizontally-ducted. I do have basement air piped up into the attic to mix air. Thanks.
Spavent,
You might want to get an opinion from Eddie McCarty at Specialized Heating & Air (404-398-3797). He has a lot of experience with split systems and Ultra Aire units.
"The specs called for an ERV and an Ultra Air 98 shows up"
It's not an ERV (or HRV). I think work should have stopped right then and there.
That was my feeling but they said they thought this would be better and said they were so sure they would switch me for an ERV within a year if I didn't think it was the right choice.
Hopefully you got that in writing.
Yes. Hopefully it will all work out. Owner is saying that they are going to install the backdraft damper, but because the minisplit SEZ runs all the time the check damper is not necessary.. I'm going to check with Ultra Air. He's going to come out next week with someone from Mitsubishi who supposedly designed my system. Also I haven't paid the final draw yet.