Dencor 200D Energy Management System Daylight Saving Time Work Around

I have a Dencor 200D energy management system that has saved me a bundle over the years. Having thought about all the excitement we will experience next weekend when daylight saving time begins three weeks before all the hardware in the US thinks it should, it dawned on me that my energy management system also will be scrogged! I worried but then I shrugged and thought "I'll figure it out next weekend!"

Ten minutes later, the guy who installed the system for me many years ago called and offered to come out and install the custom program he had developed to enable me to manually reset the clock. I thought that was pretty cool until he hit me with the punchline - $95 to come out!

I am a packrat and I saved the operating manual for the past 15 years. I pulled it out and looked at it! I decided it was pretty simple and I could do it myself and save the $95...

I am guessing that their are many others that would like to do that too... If you are one of those folks then read on... If you find this helpful, please let me know. If you have questions, let me know...

Disclaimer: This works for me. Use it at your own risk. I accept no responsibility for your actions.

My Dencor 200D Daylight Saving Time Change Work Around

Daylight Saving Time change dates are burned in to most computer hardware. The changes made by Congress in 2006 invalidate those automatic hardware driven DLST setting functions. So, the only way to adhere to these changes is to disable the DLST hardware functions and manually reset the system clock twice a year starting on March 11, 2007. Following are the MANUAL steps I use to do this – I think of my 200D system as just another clock I have to reset in the spring and in the fall when DLST changes. It is manual because the automatic hardware changes are no longer correct!

Before making the changes, familiarize yourself with these 200D panel areas:

• Go to your 200D and bring a mechanical pencil or some other pointed device that will fit into the GROUP SELECT, INCREASE and DECREASE holes on the front panel.
  
• In the upper right corner is the GROUP SELECT button and below it vertically are all the Groups (A – H). You simply press the GROUP SELECT button until the flashing light is next to the group you want to program. When you begin, there should be no Group light flashing – this is called the BASIC GROUP and this is where your system normally runs.
  
• In the left center of the panel is the INDEX SELECT button. Hold it in until you see the right number in the INDEX window to the right of it.
  
• Finally, the INCREASE and DECREASE buttons are used to select the value you want in the DATA DISPLAY window at the top of the panel.

The first change is to disable the DLST function of the 200D hardware – it is no longer correct. You will do this only once on a weekend on or before March 11, 2007 unless Congress decides to revert back to the original DLST in which case you will again want to use the automatic hardware function – I will explain below.

Disable/Enable DLST Hardware Function:

1. Choose GROUP A (bottom light) by pressing GROUP SELECT until the bottom light next to “A” is flashing.
2. Choose Index “b” by pressing the INDEX SELECT button – “b” is two presses past “9” – be sure “b” shows up in the INDEX window on the panel.
3. Use INCREASE or DECREASE to set the value in DATA DISPLAY window to either “0” or “1”. “0” turns off the DLST hardware function and “1” turns it on. A weekend, on or before March 11, 2007, turn it off - “0” in the DATA DISPLAY window. If Congress goes back to historic DLST then repeat this process and set the value to “1” to again enable the hardware function.
4. Use GROUP SELECT to go back to BASIC GROUP – no flashing lights – this is the group just above GROUP H and reset the INDEX to 1 (normal).
   

Now to set the clock manually, I use the following steps. This must be done each time DLST changes (i.e. the 2nd Sunday in March, spring forward an hour and the 1st Sunday in November, fall back an hour) – it is just another clock I have to reset twice a year on Sunday night before I go to bed!

Change the clock on the 200D

1. Choose GROUP A using the GROUP SELECT button.
2. Choose Index 6 to change the Hour (only changes the hour – that’s good)
3. In March press the INCREASE button once to spring forward one hour.
   In November, press the DECREASE button once to fall back one hour.
4. Use GROUP SELECT to go back to BASIC GROUP – no flashing lights – this is the group just above GROUP H and all f reset your INDEX to 1 (normal).

That’s all I do and it works fine for me… If you now feel competent to do this, it will save you a service call and/or money!