In my area, most 1600 sq ft house of the same time period could be easily heated with a 60,000, 90%er. We usually get a little colder.(but not these last 2 years)
What size was the old furnace. A load calc can be fudged to say a size a contractor wants it to say.
Is it wired for 2 stage operation, or do they have it on a timer that it goes to second stage every cycle.
3 contractors sized it when I got independant quotes. You saying all three fudged the numbers?
Also the previous furnace was an 85k, but yet another contractor. AND the original furnace was 80k. The previous furnace (85k) was removed due to issues with not turning on the blower when the DX ran. The contractor could not fix that issue.
Since I helped install and wire the furnace, I know it is right. I also ran the thermostat in test mode to double check. All delta T's across the HX were right smack in the middle of the manufacturer's specs for temp rise (both speeds), without changing speed taps. External static pressure is fine, and no my house is not a wind tunnel. Actually I hear slightly less noise than the other furnaces while airflow is comparable and not excessive or too low. My curtains (shears actually - not my choice) move only slightly when the fan is on, similar to the other furnaces. Everything matches up. The only issue is the indicated temperature never changes and the excessive on-off cycles. My Robertshaw/Invensys Insight thermostat would show the temp change. I had the opportunity to watch as my VisionPro was out for repairs. And yes, the thermostat is in a very good location.
With 1 CPH being set, it NEVER changed indicated temperature over the 1/2 hour it ran this morning while I watched. This was after recovery on both days. I know my other stat would have and did show temp variations more than 1 degree during a similar runtime with the same furnace. I do admit the temperature is more even with the VisionPro, but it is not worth the extra wear and tear on the equipment.
This weekend will be the test as we will be in single digits. I know the current setting is good for the balmier temps, like this morning. So, we shall see what colder temps do.
I am glad to have the ability to set CPH, but I still would like a more thorough description as to what algorithm it uses to determine when to cycle on and something more than second stage comes on when it thinks it needs to or sees the temperature drop. PID loops are nice for even temps, but they also make the equipment wear out faster.
Basically, I like the thermostat as it is easy to use and setup. I also like the touch screen. Just the quirk of control.
Is it possible to email them for answers?
Thermostats actually read in tenths of a degree, you should never see the room temp move if the anticipation circuit is working correctly. You need to measure the cph before assuming oversized unless of course its grossly obvious as I'm sure we have all seen a time or 2.
Originally Posted by y2kjackal
Depending on the brand of furnace--most upstage to hi-fire after 7 to 10 mins.
Not if your not using the timer.
Originally Posted by comfortking88
Not saying they fudged the nmbers, just that its easy to do.
Originally Posted by beenthere
When it gets down to the single digits, time how long it runs. It should be Almost continous.