"HVAC Guy" wrote in message ...

Of course not.

Because the number of cycles per hour will depend on

- the temperature span or hysteresis around the desired set point
- the heat loss of the space being controlled
- the BTU capacity of the furnace

If the stat has a setting for cycles per hour, then you're going to have
a variable hysteresis, and the stat is going to take some time to learn
what that's going to be for a given set of conditions.

To make it more complicated, the heat loss of the space is going to be
affected by ambient outside weather (wind and temperature) and how well
the space is insulated. As that changes, the thermostat will have to
re-learn how to control the furnace to keep the desired set-point while
maintaining the desired cycles per hour.

It's far simpler to set the hysteresis (2 or 3 degrees instead of 1
degree) and live with what-ever cycles per hour you end up getting,
rather then aim for a set or fixed cycles-per-hour.

Did you read any of the PDFs?

Anyway the problem here isn't Honeywell's choice of CPH over hysteresis
degrees, it is how this stat (RTH221) seems to function, when set to 5 CPH
it calls for heat every 12 minutes as expected, but when set to 3 or 1 CPH
in my house it only drops to calling for heat every 13 minutes, and this is
after several hours to adapt. I have a 90+ condensing gas furnace and this
style is only supposed to be cycled about 3 times per hour.

Also interesting with this model is that when set to 62° F as it cycled its
reading would swing from 58° to 65° with each cycle while 3 other
thermometers, a non-connected Lux digital thermostat, a digital meat
thermometer, and an indoor/outdoor thermometer and hygrometer weather
station all placed right beside the RTH221 would all show the swing as being
from 61-63°. When the temp setting on the RTH221 was first set down to 62°
from 68° its reading quickly dropped to 61° and stayed as the 3 others
showed the normal gradual drop. When the others started to show 61° as well
the RTH221 dropped to showing 60° and shortly thereafter called for heat.

It is an odd model for sure.