Instruction: Extract information from the supporting document to answer the given question.

Input:
Question: Does the unit work if I only install the motion detectors? If it can, do you have to unprogram the other units or can you just leave it unpowered?
Document: Even prior to purchasing. They are very good. I had to watch a few over & over, & soon it all comes together. Knowing what I know now. I could install & program the system ( I have 8 window/door sensors & 2 motion detectors ) in an hour. It's a little complex at first, but work through it & nothing else can touch this system. A couple issues: 1} I have had one motion detector have three random trips.
The Security System was delivered in just a few days. It only took us an hour or so to install it throughout the house. Seems to work very well, gives me much Peace of Mind, when I go to bed at night, knowing the system is on, running and protecting my home and family. The only problem I see is if the system is armed and you happen to leave a door or window open it doesn't tell you.
Easy to record an outgoing message and will dial several phone numbers. Easy to program. And, should you need extra door or motion detectors, they can be purchased here at Amazon. One word of caution. We decided not to use the motion detectors as they are extremely sensitive. Our central heating & cooling unit makes the blinds flutter and even this small amount of motion will be picked up.
The sensors were easy to install. The motion detectors are better than I expected and are placed high so the dog will not set the alarm off. It is a great system for the price without a monthly bill. Glad I purchased it.
The system was pretty easy to install. Everything is synced right out of the box. A little unfriendly to set-up the preferences, but I've seen worse.Two issues that keep this at 3 stars for me.1) the motions sensors are battery hogs! I wishful here was a way to adjust the sensitivity on the units. Maybe that would save some battery life. I was able to adjust a set of jumpers inside the unit to turn off the status LED.
I bought this product few weeks ago because I needed a basic system to protect a rented condo unit. This system had the right amount of sensors that I was looking for; 2 motion + 5 magnetic. The delivery was quicker than expected and it was easy to install for testing. The seller (Mike) was so kind that had already programmed in advance all the sensors. This saved me time.
The door monitors and motion sensors work very well and are easy to install. Overall, we are really pleased with this alarm system. I'd definitely recommend it if you need a great security system that is affordable and easy to deploy.
everything about this item was wonderful, except it didn't work. Sounded wonderful, nice features, already setup. I spent four hours setting up the system, mounting units into the walls, door and windows, seemed to work fine. Noticed problem if a window was already open, system wouldn't arm; this can be a problem in the summertime, and I didn't understand why if the window sensors keyed off of the magnets being moved, but whatever.
Very handy set for starting your home security system. I love every piece of the set esp. the motion detectors.
I set up a Fortress S02A system about 10 months ago and it has performed as advertised. My system uses the two battery-powered motion detectors that came with the kit.
Answer: yes, i dont use the doors and windows units. they are not very reliable. the motion detectors are the best. everything comes programed but you can only use the motion detectors. another point, the motion detectors i only have to change the baterries every 6 months or so.