10
NOTE:
The Temperature Rise Tables can also be used to estimate
the air handler airflow delivery. When using these tables for this
purpose set the room thermostat to maximum heat and allow the
system to reach steady state conditions. Insert two thermometers,
one in the return air and one in the supply air. The temperature
rise is the supply air temperature minus the return air temperature.
Using the temperature rise calculated, CFM can be estimated from
the TR formula above. See Spec Sheets and/or Service Manual for
more information.
Comfort Setting Menu (CFS):
There are 6 options
available in the Comfort Setting Menu which impacts
system target run time and electric heat functionality.
Electric heat operation adjustments only apply if a
communicating heat pump is installed. Comfort Setting
Options 1 – 5 have set values for the System Target
Runtime and option 6 enables additional menus to
customize all comfort settings. See list below for the
System Target Runtimes associated with the first 5 Comfort
Settings. These first 5 options are setup to help satisfy the
thermostat slower or faster based on the selection where
option 1, with a 10 minute Target Runtime, is attempting to
satisfy much faster than option 5, with a 30 minute Target
Runtime.
System Target Runtime:
Comfort Setting Option 1) 10 Minute System Target
Runtime
Comfort Setting Option 2) 15 Minute System Target
Runtime
Comfort Setting Option 3) 20 Minute System Target
Runtime
Comfort Setting Option 4) 25 Minute System Target
Runtime
Comfort Setting Option 5) 30 Minute System Target
Runtime
Electric Heat Adjustment:
This system will automatically
determine if the heat pump is capable of satisfying the
thermostat in the selected System Target Runtime. If the
heat pump is unable to satisfy in the selected time, electric
heat settings will determine how many attempts should be
given to the heat pump before temporarily locking it out
and using the furnace. These electric heat settings also
determine at what time the system should remove the
temporary heat pump lockout and run the heat pump again.
There are four adjustable items associated with back up
electric heat operation control. In the same way as the
System Target Time, each of these items have defaulted
values for Comfort Settings 1 – 5. Only when Comfort
Setting 6 is selected will each item be available for full
adjustment.
1.
Stage Up Percent (7 segment menu SUP):
This is a value
that determines how far past the target runtime the system
should continue running the heat pump before transitioning
to the furnace. For example, assume this menu was set to
20% with a target runtime of 20 minutes. If the thermostat
did not remove the heating call after 20 minutes, the system
would allow for an additional 20% heat pump run (20% of
the 20 minute target is an additional 4 minutes). In this
case, the system would turn on back up electric heat after
24 minutes if the thermostat call was still present. Each
time this occurs, the system records this as a strike against
the heat pump (the strike is important when looking at the
Over Target Threshold)
2.
Over Target Threshold (7 segment menu Ott):
If the heat
pump has consecutively activated back up electric heat
for the selected Over Target Threshold amount of times,
meaning for this many consecutive cycles it has been unable
to satisfy the target time by itself, then the heat pump will
be temporarily locked out and the furnace will become the
primary heat source.
3.
Stage Down Percent (7 segment menu SdP):
This only
applies when the heat pump and back up electric heat are
activated on initial start-up. In this case, the system will try
to determine when the best time to operate the heat pump
individually again. To determine this, the system looks at
how easily the air handler is able to satisfy the thermostat
using the heat pump with back up electric heat. Assume this
setting is 15% and the target time is 20 minutes. If the heat
pump with back up electric heat can satisfy the thermostat
in less than 17 minutes (20 minutes - 15% = 17 minutes)
then the algorithm records a strike against the air handler
(this strike is important when looking at the Under Target
Threshold).
4.
Under Target Threshold (7 segment menu Utt):
If the air
handler is able to satisfy the thermostat using the heat pump
with back up electric heat for the selected number of consec
-
utive cycles the electric heat operation will be temporarily
removed. The heat pump will then be used during the next
cycle. If the heat pump can satisfy the thermostat in less
than the System Target Runtime the back up heat operation
will be completely removed and the heat pump will become
the primary heat source again. if it fails to do so, the strike
count against the furnace will be reset and the furnace will
remain the temporary primary heat source until the Under
Target Threshold is reached again.
The system will automatically make adjustments in an
attempt to satisfy the thermostat as close to this target
runtime as possible. After a power cycle or mode change
(cooling to heating or heating to cooling) the system will
run full capacity for the selected mode during the first
thermostat call. Based on the selected target runtime and
how long the initial cycle takes to satisfy the thermostat,
the control algorithm will adjust the system stage times for
a 2 stage unit or the capacity demand percentage for an
inverter / modulating unit for the next cycle. Note: actual
runtimes may change depending on variations of load
throughout the day.
The following table shows the default values for all Comfort
Setting Options (1 – 5)
