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Trying to solve VVT issues

2 years ago

Can I just open up all of my VVT dampers, disconnect them and just use an averaging thermostat?

Comments (6)

  • PRO
    2 years ago

    VVT is a carrier designed communicating type zone system that runs via variable volume / variable temp to the zone(s) being controlled.


    It was more or less designed for smaller type HVAC systems 3-20 tons or so and to have as many as 5-15 zones with design limitations of up to 32 zones per system (like if the system in question was for a 20 ton roof top unit) -- commercial type application. Most applications were for 3 to 15 zones.


    As I've said countless times on this board -- communicating systems, whether they be the system themselves (no zoning the equipment zones the space) or attaching yet more proprietary controls to zone the system to control it... everything works great when everything is behaving properly. When it's not is a prelude to ECH. (error code hell)


    If error codes are being spit out, things tend to grind to a bitter end and the resolve is thinking that just disabling or doing away with one part of the communicating system can be aleviated with a new gadget that "in it's own right" will perform a miracle to solve all the problems the proprietary zone system can not.


    Can you disable the zone system & install a newer cheaper gadget? Sure. Doesn't mean it's going to work though. (I use the word "work" here loosely... some aren't looking for what is proper, they just want something cheap. Cheap and 2023 don't go well together... (INFLATE and exhale, LOL)


    If a cheaper averaging thermostat did the work of a *properly installed zone system* there would have been no need for Carrier or others to spend the time developing a proprietary controlled zone system.


    To be clear: I am not a pyschic and the OP did not spend the time specifying *EXACTLY* what VVT issues he's having. (What I put here is a guess from 30 years experience in HVAC by yours truly.)


    What we don't know and should know:

    How old is this system?

    What VVT issues are plaguing this system?

    Is it VVT or problems with the equipment that is causing the issues?

    How many times has this system been repaired and was it the *original installing licensed contractor* making those repairs? If your repair mantra is just to run to another contractor because of xyz excuse you may have inadvertently brought the trouble on yourself.


    If it is the original installing contractor: what is he recommending?



    What is a guess worth in 2023? Hang on maybe we'll find out. Or someone is going to be offended with the laundry list of truths I've provided here. LOL> big smiles.


    I service the Katy, Texas area.

  • PRO
    2 years ago

    "Can I just open up all of my VVT dampers, disconnect them and just use an averaging thermostat?" In a word, yes. Doing so will convert your multi-zone HVAC system to a single-zone system.

  • 2 years ago

    Thank you Charles, all i will need to do now is make sure it’s balanced! By the way im just looking for something that works, not cheap. This system has never worked properly from day 1 and most controls guys have told me that they shy away from them. I could see it working if they controled both supply and return instead of a common plennum. 👍

  • PRO
    2 years ago

    Balancing air flows can be a frustrating and time-consuming process. If you have access to an AABC-certified or NEBB-certified technician I recommend you hire them. Otherwise, plan on a long, drawn out process. Alcohol helps.

  • 2 years ago

    👍

  • PRO
    2 years ago

    By the way im just looking for something that works, not cheap. This system has never worked properly from day 1 and most controls guys have told me that they shy away from them.


    Communicating systems attached to proprietary communicating zone systems will remain communicating once the zone system is disabled / bypassed.


    Choosing a non communicating thermostat to control a system that was designed to be communicating will most likely cripple the system to a certain degree.


    The definiton of "something that works" is likely going to get a work out here.


    Alcohol isn't recommended. (Mixing alcohol with HVAC problems? Not wise.)