Honeywell EXCEL 5000 User Manual page 168

ALPHABETIC REFERENCE
Minimum room temperature protection There are two ways of controlling the minimum room temperature during un-
Minimum Room Temperature Protection The minimum room temperature protection ensures a minimum room temperature
Minimum Room Temperature Control
74-5577–33 (US)
EN2B-0184 GE51 R0518 (Europe)
flow temperature control
No room sensor connected
control with night set-back
with room sensor
control with total cool-down and minimum room temperature protection
heating pump control
On
continuously ON
Off
Note: The heating pump must be controlled externally.
occupied periods
• Minimum room temperature protection
• Minimum room temperature control
To enable minimum room temperature protection, set P24 to a higher value than the
value of the room temperature setpoint during un-occupied periods.
To enable minimum room control P24 must be set to a value lower than the room
temperature setpoint during the un-occupied periods.
condition during un-occupied periods. If the room temperature drops below the value
of the P24 setting, the mixed water temperature setpoint is set to the value of the
Tprot. The minimum room temperature protection function ends if the room
temperature rises above the value of P25 + P24. This leads to the reasonable heat
up of the room. The next figure shows the minimum room temperature protection
function.
Tprot = HC (P24 + P25 + 2K, TOat, P15, P16)
minimum room
temperature protection
°C
mixed water temperature setpoint
Tprot
0
°C
P25
P24
room temp setpoint
The minimum room temperature control becomes active, when during un-occupied
periods the room temperature drops below the value of the room temperature
setpoint set in the time schedule. In this case, the heating circuit is re-started and
calculates the mixed water temperature setpoint depending on the heating curve
characteristics, outside air temperature and the actual room temperature setpoint.
This function is an alternative for minimum room temperature protection whereby
always maximum capacity is used. To enable minimum room temperature control,
set P24 lower than the value of the room temperature setpoint during un-occupied
periods.
170
EXCEL CARE CONTROL ICONS
control with total cool-down
controlled by heating circuit
frost protection limit
time
room temp
time
outside air temperature