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  1. #1
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    Sep 2019
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    Inverters and BAS

    I'm trying to figure out how to do some smarter controls for a lab space I've got.

    Lab is fed by the main air handler, using VAVs, to do some cooling. Additional heat load was added (incubators, freezers, thermocyclers, and other heat generating lab equipment) and the lab had trouble maintaining temp. Mini splits were quickly added. 2x 2ton Fujitsu inverters.

    It's been an ongoing problem with the VAVs fighting the minisplits, summer and winter, both trying to add cooling or heating.

    I'm extremely weak on the control side of mini split inverters. I've been trying to make heads and tails of the manuals on these units trying to figure out if there is a low voltage I can cut and run through a relay controlled by the BAS.

    Beyond that, is there a thread where I can read up more on the principles of inverters and their controls? It appears that most mfgs have proprietary boards, but I would think they would all use the same fundamentals.

    TLDR:
    Where can I install dry contacts to turn an inverter on and off with BAS?

    Where is there a course for learning how inverters in general work in HVACR, preferably not mfg specific?

  2. #2
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    Mains.

    kontrol out
    "Good" - Jocko
    "Open is as open does." - Forrest Gump
    "Can't we all just get a Lon?" - Garry Jack
    "BACnet: integration or interrogation?" - The Janitor
    "Interoperability? You can't handle interoperability!" - Nathan R. Jessup
    “What’s that? Aaa… open protocols? Don’t talk about…. open protocols? Are you kidding me? Open protocols? I just hope we can hardwire an interface!” - Jim Mora Watch it here!

  3. #3
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    Your options are pretty limited. Would look in whatever gateways they offer for those and expect little better than cutting mains to it.

    That's some fairly expensive gear in a space to half a$$ the HVAC. Guessing they are going to regret saving a few bucks vs dealing with that over the lifetime of that lab.

    Looking for another bandaid for your critical area, pass and thank you...for the WOS pictures.
    Propagating the formula. http://www.noagendashow.com/

  4. #4
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    Thread Starter
    You are correct. It's a bit on the undersized end now. The building dates back to the 70s, and has a 90s Trane air handler, and is one of the least properly equipped spaces we've got to work with. Patchwork is the name of the game until some land opens up to build new lab space for our needs (instead of retrofitting old buildings in a university park to meet current expanding space requirements).

    Cutting the mains is the obvious. If I can't get anything back from the mfg by the end of the week, I planned on doing just that (and hoping the controller goes back to it's setpoint on the cassette).

    Thanks for the input though.

  5. #5
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    Agreed with previous statements, might help to widen out your setpoints between heat and cool as well. Worked on a CSI lab with similar issues...

    So do you own a Velociraptor truck?
    "How it can be considered "Open" is beyond me. Calling it "voyeur-ed" would be more accurate." pka LeroyMac, SkyIsBlue, fka Freddy-B, Mongo, IndyBlue
    BIG Government = More Dependents
    "Any 'standard' would be great if it didn't get bastardised by corporate self interest." MatrixTransform
    My 5 yr old son "Dad, Siri is not very smart when there's no internet."


  6. #6
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    CM - currently removing those old controls from the CSI lab and upgrading them. Brian from T&M said to say hi.

    kontrol out
    "Good" - Jocko
    "Open is as open does." - Forrest Gump
    "Can't we all just get a Lon?" - Garry Jack
    "BACnet: integration or interrogation?" - The Janitor
    "Interoperability? You can't handle interoperability!" - Nathan R. Jessup
    “What’s that? Aaa… open protocols? Don’t talk about…. open protocols? Are you kidding me? Open protocols? I just hope we can hardwire an interface!” - Jim Mora Watch it here!

  7. #7
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    Cool! Good luck with that project...from the little I've been aware it's been a bunch of band-aide's. Controls and limited access one only can do so much.
    "How it can be considered "Open" is beyond me. Calling it "voyeur-ed" would be more accurate." pka LeroyMac, SkyIsBlue, fka Freddy-B, Mongo, IndyBlue
    BIG Government = More Dependents
    "Any 'standard' would be great if it didn't get bastardised by corporate self interest." MatrixTransform
    My 5 yr old son "Dad, Siri is not very smart when there's no internet."


  8. #8
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    Well they're finally adding a second chiller and that was the catalyst to upgrade the system. T&M have not be happy with the previous system and service.

    kontrol out
    "Good" - Jocko
    "Open is as open does." - Forrest Gump
    "Can't we all just get a Lon?" - Garry Jack
    "BACnet: integration or interrogation?" - The Janitor
    "Interoperability? You can't handle interoperability!" - Nathan R. Jessup
    “What’s that? Aaa… open protocols? Don’t talk about…. open protocols? Are you kidding me? Open protocols? I just hope we can hardwire an interface!” - Jim Mora Watch it here!

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