Honeywell EXCEL 5000 User Manual page 184

ALPHABETIC REFERENCE
74-5577–33 (US)
EN2B-0184 GE51 R0518 (Europe)
The shortest advancement of start-up is set by Parameter P3 (lowest pre-heat). You
must set this parameter to its lowest value so that the calculated start-up point is
valid. The parameter's maximum limitation is 1080 min (18 hours).
The minimum limitation of advance time is 0 minutes. When room temperature
setpoint corresponds exactly to actual room temperature, system start-up matches
the switching point in the Time Program.
Between these two limits, advancement of system start-up (t VHE ) is calculated with
the following formula:
t VHE = (X2 - X3) * P4
In other words, early switch-on time equals room temperature setpoint minus room
temperature multiplied by the high-speed preheat factor. The high-speed preheat
factor indicates how many minutes the system requires to compensate for a
deviation of 1 degree. It must be entered in Parameter P4, but EOV can
independently correct it. See Adaptation of Factors in this section.
Optimized Shutdown in the Heating Mode
If the Time Program contains a switch point that shuts the system off while the
system is in heating operation (XD5=1), EOV optimizes this switch point, that is,
EOV shuts down the system before reaching the switch point so that energy is
saved. EOV calculates shutdown advance time (T VHA ) the same way as EOH,
using a linear characteristic curve.
EOV shuts down the system with the maximum time advance if OAT is equal to the
room temperature setpoint and room temperature. In this case, EOV guarantees
that the room temperature setpoint is closely followed until the switch point is
reached in spite of early shutdown as the heat losses from the building are zero
because of OAT.
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EXCEL CARE CONTROL ICONS