Sentinel DEC-4 Digital Environmental Controller

Day / Night Cooling, Heating, CO2 and Humidity. Coordinated CO2 Outlet

Additional Information

Name Sentinel DEC-4 Digital Environmental Controller
Brand Sentinel
Warranty 3 Year
Voltage 120v
Amps 15A
ETL Listed Yes
MSRP $264.95
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Comes With:
  • New remote combination temperature humidity and light level sensor allows users to take accurate plant-level readings up to 15' away from the DEC-4 base unit.
  • Heavy gauge #14 AWG cables and wire.
  • Super-duty 30-amp relays for long life.
  • Power switch and re-settable 15-amp circuit breaker provides over-current protection.
  • 100% digital Temperature
  • Easy to use pushbuttons that are simple to understand

  • Separate Day / Night Cooling setpoints.
  • Separate Day / Night Heating setpoints.
  • Separate Day / Night Humidity setpoints.
  • Minimum / Maximum recall of temperature and humidity readings.
  • Temperature: Two independent outputs to control cooling and heating with separate Day and Night settings for each.
  • Humidity: Can either increase or decrease the amount of humidity inside the area with separate Day and Night settings.
  • CO2 Coordination: Allows for basic coordination of CO2 enrichment with daytime settings, ventilation cycles etc. This allows for increased growth, lower cost of CO2 enrichment as well as lower power consumption in your garden. Manufacturer set CO2 enrichment at 1250ppm.

How to use:
  • The unit comes with a metal bracket that is first attached to a wall. Secure the bracket to the wall with 2 screws. Then use the 2 thumb screws to secure the enclosure to the bracket.
  • The unit requires a 15-amp power supply. Plug the power cable into a standard Nema 5-15 wall outlet. The built-in circuit breaker will protect the unit from overloads.
  • The device(s) that will be controlled by the DEC-4 must be 15-amp or less COMBINED load. Cooling, Heating, Humidity and CO2 devices each have their own receptacle. The CO2 receptacle will activate a CO2 device independently or coordinated with cooling devices and built-in light sensor.

  • Cooling devices such as ventilation fans or air-conditioners connect to the Temperature Device.
  • A humidifier or dehumidifier can have searate Day and Night settings and is connected to the Humidity Device receptacle.
  • Heaters for cooler climate greenhouses connect to the Heating Device receptacle.
  • Connect your CO2 generator or compressed CO2 solenoid/regulator assembly to the CO2

Power Supply Voltage 120 V~ / 60 Hz
Circuit Breaker Rating 15A / 120V~
Temperature Operating Range 0'C/32'F to 49'C/120'F
Temperature Accuracy +/- 1'C/1.5'F
rH Operating Range 0-95% rH
rH Accuracy +/- 3% rH
Temp / rH Hysterisis User Selectable
Temp / rH Control Independent or Connected
Temp / CO2 Control Independent or Connected
Dimensions 8" x 6.5" x 3.1"

Customer Reviews

Add Your Review
False reading within a week Review by Steve
Overall Rating
In the past my Sentinel controllers have lasted years. This DEC-4 was reading 93 in a room that was 74 within the first week. Sentinel would not answer their phone, return a call or reply to my emails. I tried to get a hold of them for 2 weeks. If this Controller worked it would be great. A 5 year warranty is useless when the company offering it is 100% incompetent. (Posted on 7/17/2018)
Okay Review by Bernadette
Overall Rating
Co2 is not regulated as to previous reviewed by Piggy Sqishy. Sensor detecting relative humidity was high by 9%. Would have to send the whole unit back to have it recalibrated. The other receptacles work fine and overall for 200 bucks the Sentinel DEC-4 is not a bad deal. (Posted on 1/1/2018)
I would never go without it ever again Review by Piggy Squishy
Overall Rating
When I got mine, it did have an issue, but Sentinel was very quick to jump up and warranty the product and get it fixed and back in my hands in a timely manner. With a 5-year warranty, when others are only 1-3 yrs it was very important to me before even buying this product to know how they would really handle a warranty claim, and I wasn't disappointed. The guy even told me, others have felt another company was better and switched, only to return and tell us we still are truly the better company; and I agree with this fact having done my own research before buying mine and calling each company to ask lots of questions.

The description above sells this model short in my eyes, they says it has a CO2 plugin for your CO2 device, and it does... but they do not tell you that it controls your CO2 levels for you. It is factory set to come on around 1100-ppm and shut off at 1300-ppm for your CO2. They also do not tell you that you can set it for Day Free, the CO2 outlet is on 100% of the time during daylight hours if you use another CO2 regulation system. Day Lock, where you want the DEC-4 to control the CO2 levels for you, and Night Mode for those who are growing mushrooms and need the CO2 on at night, not during the day for those growing plants.

When they talk about you can set the Day & Night Values, they really put that control into your hands by letting you set those numbers where you want them and then being able to set the values between them as well. It truly gives you a precise control so whether its is a small system or a large system you can set those values where you need them to meet your intended goals and not be limited by your equipment. What I mean by this, if you want you Day Temp to come on at a set temp and run until its a 2-degree difference and then shut off, or an 8-degree difference, then that is what you set both for the Cooling and Heating separately. It even allows me to do that with the Humidity as well, so you don't cycle on and off every couple of minutes on a small system, or have massive swings in a larger system.

Again they put the control in your fans and you tell the system if your Cooling fan exhausts the air and pulls in fresh air, or if its a closed system and it doesn't matter if the CO2 is on when the Cooling fan is engaged. Again giving you the operator full control over your needs and your system. The only complaint about the entire system the probe does not disconnect from this system, the wire for it comes straight from the controller to the probe and no way to ever change it. However for the price and what you get, you will not find it in another controller and certainly not for this price, I did look and I looked hard... and this was truly the best deal and at the price that makes it more than a bargain.

If all that you are now left wondering is "Do I really need this kind of a system?" I can tell you from personal experience, this has more than paid for itself in the problems and issues it has helped me prevent by being in such precise control over my environment. My personal biggest regret I didn't find and buy this years ago, because it still is one of the best investments I ever decided to try on the hope it would be worth my time and money. (Posted on 9/25/2016)
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