DIY Controller for HVAC Electric Dampers

Maker, DIY
1

Hi,

I have 5 electrically controlled HVAC normally-closed dampers in my basement. Each operate on 24 VAC @ .25Amps (6 watts). Each unit comes with a 24VAC 15VA transformer but you are only supposed to use a max of 2 per transformer. The wires all terminate in my furnace room where I have been manually hooking them up.

I’d like to build a control device (ideally utilizing a single, more capable transfomer) that I can operate from my iPhone.

Thoughts?

Thank you.

2

Hello,
Welcome to the DigiKey TechForum. We have these transformers you can look at as possible options. I don’t have the experience to assist with building a control device but since this is a public forum someone may jump on and offer advice on how to develop this type of system.

3

Hello @BigFriendly,

Home automation is an emerging field. Your idea for controlling the devices via a cell phone is certainly possible.

As a starting point, may I recommend you explore “smart home devices.” Consider learning about nodeRed. Also, I encourage you to explore applications of the Arduino Opta and expansion modules.

Please let us know if you have questions about a specific application, technology, or component.

Best wishes,

APDahlen

4

Hi BigFriendly ,

For a more finished product, you may choose to buy a “smart outlet” such as 4259-DPS1101S-ND (click here) and wire the transformer(s) into that using plug Q526-ND. This utilizes your Wi-Fi and is controllable through your cell via the free eco4life App. These are in stock and ship within one business day.
image
image
image
image

Smart wireless outlet plug. Remote access and control. No hub is required. Voice command works with Alexa and Google Assistant. Set schedules. Scene setting.

  • No Hub Required. Based on Wi-Fi technology and requires no other hardware to work. All you need is a Wi-Fi network to connect your smart plug, and you are all set to navigate all features through your smartphone.
  • Control From Anywhere, Anytime by App or Voice Control. Plug any device into the smart plug, and be in control anywhere, anytime using the eco4life app. Works with Amazon Alexa and Google Assistant.
  • Set Schedules and Multiple Timers. Create schedules to automatically turn your appliances ON/OFF. You can even set multiple timers on the scheduling program. The eco4Life app allows you to share access with family and friends, allowing them to control when you are busy.
  • Reliable and Safe. The smart plug carries all the necessary international standards and certifications such as FCC, ROHS, ETL, and cUL. Material is made out of fire-resistant housing. The smart plug is protected and so are you.
  • Easy Setup with App. Download the eco4life App, and follow instructions as easy as 1-2-3. The eco4life app allows you to add as many smart plugs as you want to monitor and control.

Specifications:

  • Input:120V-AC 60HZ 10A
  • Output:120V-AC 10A Total Max
  • Output Power:1200W Max
  • Wifi:2.4GHZ, IEEE 802.11 b/g/m
  • Working Temperature & Humidity: -25℃ - +40℃/10%-90%
  • APP Support:Android and IOS
1 Like
5

Thanks to everyone who replied.

Ryan, I hadn’t even considered your suggestion of simply running each transformer off of a basic wifi enabled wall plug. Even though that would mean multiple transformers, it’s much simpler than messing with relays after the voltage comes out of the transformer. Genius! Thanks!

1 Like
6

Hi @BigFriendly ,

My appologies, I forgot to mention:
When the transformer is always “On” or powered, it would not produce a transient output voltage to the damper system. However, when switching the transformer input voltage from Off to On via a smart outlet, there may be a brief surge of voltage due to inrush current. This surge typically occurs for a very short duration, usually in the milliseconds range. The surge voltage can vary depending on the specific transformer and the load connected to it, but it’s generally higher than the nominal voltage for a very brief moment.

I am not sure if or how this may affect your load and whether or not it would be sensitive to this slight increase in transient voltage. But it is something to consider, one of our engineers may possibly further comment on this or someone whom has more experience with damper systems.

Also remember, that dampers may be controlled from a digital or analog signal instead of being able to open/close based on power input only.

Please share with us your findings!

Regards,

7

Hello @BigFriendly,

Please tell us more about the dampers e.g., manufacturer and model; include picture if you can.

My concern is that the damper will not self-close when powered down. For example, a motor-powered damper will not close when power is removed. Instead, it will simply stay in whatever physical position it is already in.

Sincerely,

Aaron