cyles per hour

[northof49]

I am programming my new Honeywell vision pro 8320 and at one point it asks how many cycles per hour do I want??? I have a heat pump with a 96 % gas furnace as back up. It suggests a setting of 3 cph for this set up so thats what I went with.

What cycles are we talking about her Vern? (you will have to be plus 55 to know about the reference to Vern).

Thanks, North

[jacob perkins]

how many times the unit comes on(cycles)per hour.

I dont know that much about programing anything,but I can tell you that is a good feature to have.I am assuming it is there to prevent short cycles and will override if longer run cycles are called for on cold days.Three sounds good.

[northof49]

Okay...........so then if I have the anticipator set for 1 degree celcius and the temperature varies more than that, for more than 3 times in one hour then the furnace won't come on??
Am I followning this correctly?

North

[jacob perkins]

now you are confusing me.hopefully someone who really knows this stuff will come along ...there is a bunch of them here.

somehow the programing makes the unit come on a maximum of three times per hour.that is good because it is more econmical and causes less wear to equipment.how the programing does it? i dont know what to say...it manipulates the readings to cause the desired outcome.

now having said that,someone might come along with a more informed answer.that's the way it works here.

[northof49]

Well one thing I have found from lurking on this board is that there is certainly no lack of opinion..........LOL!

Anyone out there who can clear this up?..........hello!

[edward301]

I have a couple of Vision Pros installed at my home,
and if it is set to 3 cycles per hour, that is what
it will allow.

If the temperature varies more that three cycles, it
will delay, or hold on to average out the cycles. So
at times your temperature will fluctuate beyone this
1 oC setting.

[cem-bsee]

most rotating motors & compressors ( X for vehicles ) rated for no more than 4 starts per hour!

[garry b]

Northof49: Or should I say "Hey, Vern. It's your good buddy Ernest, here". And I'm quite a ways from 55... If you have the cycles per hour too high, the thermostat will narrow the differential between "call for heat" and "heat satisfied". Basically, if you allow it too many cycles per hour, it will use that to run the furnace up to that many times per hour to keep the set temp. So, if you say six per hour and set the temp at 21 deg C, it might set the range to 20.8 (call for heat) and 21.3 (heat satisfied). If you say three per hour, it might set the range to 20.5 to 21.5. So, the more cycles, the less drift allowed from the set temp. The less cycles, the more drift allowed from the set temp.

i.e. My father-in-law had a VisionPro thermostat installed last winter. I was over after that and would hear his furnace start and run for only about five to 10 minutes (can't remember exactly). Regardless of how long(or short) it ran, I could tell it was short cycling. What was happening was that the thermostat was trying to keep the temperature as close to the set point as it could. This was all due to the thermostat installer dialing up 6 cycles per hour. Once I got my hands on it, I set it to 3 or 4 (can't exactly recall). This made the thermostat widen range in temp before it would "call for heat" or say "enough heat". Now it cycles and runs for 15-20 minutes each time.

[tpa-fl]

The other thing to keep in mind is that longer cycles = better efficiency. The first few minutes of operation (heating or cooling) are the most inefficient time. You're waiting for the heat exchanger & ductwork to warm up or waiting for the evaporator coil & ductwork to cool down. With single stage AC's, it can be up to 10 minutes before everything's cooled down to the optimum temperature.

As posted by others, longer cycles = less comfort (theoretically). And yes, if you set it for 1 cycle per hour, there's a good chance that comfort won't be all that great. BUT, 3 cycles per hour would mean ~20 mins per "cycle". Now, the cycles per hour is the maximum # of cycles the stat will do, and it will do only 1 cycle per hour (or less) if need be (extreme heat/cold outside).

[northof49]

Got it guys.........thanks a million.

North