User Manual

4/4 23.03.2005 CE1G2725en Building Technologies / HVAC Products
Sensor calibration
• Generally there is no need to calibrate sensor, however
the displayed room temperature on the QAX850 LCD can
be calibrated if there is any discrepancy from the actual
temperature measured with a certified thermometer. cali-
bration function can be accessed by pressing the
and
buttons simultaneously for 5 seconds. Displayed value
can then be adjusted via the same buttons in 0.1K steps.
Range is +/- 3K.
Parameter list
Line Function, display Range
Explanations, notes and tips
P00 Temperature scale °C/ F°
P01 Frost protection limit in OFF mode Off/5..8°C
If temp is below the set limit, heating will be activated
P02 Over-temperature limit in OFF
mode
Off/30..35°C
If temp is above the set limit, cooling will be activated
P03 Min. OFF time delay 0..600s
Min off time is used to prevent short cycling of compressor
P04 Min. ON time delay 0..600s
Min on time is used to prevent short cycling of compressor
P05 Dead band between cool and heat
OFF points
0.5..6K
Zero energy band. When actual temp is in dead band, outputs are off
P06 RV ON in heat or cool mode Heat/Cool
The reversing valve(RV) can be energized in cooling or heating de-
mand. Dependent on the internal equipment circuitry
P07 Fan run ON after heat output turns
Off
0..300s
Fan run ON delay is used to remove the residual heat and to prevent
the high limit electric heater thermostat from tripping off
P08 Fan run ON after cool output turns
Off
0..300s
Fan run ON delay can be used to make use of residual cooling and to
remove condensation
P09 FCU flush pipe time 120..600s
On start up, the controller will open the valve (flush time) and the sen-
sor will detect for hot or chilled water in the system. Only for 2-pipe
FCU, appl. A8
P11 Water temp heat mode change-
over
22..32 °C
Only for 2-pipe FCU appl A8. This is the water temp setpoint for heat-
ing
P12 Water temp cool mode change-
over
10..21 °C
Only for 2-pipe FCU appl A8. This is the water temp setpoint for cool-
ing
P13 Fan auto-speed high range H:80..100% Switching point for high speed fan
P14 Fan auto-speed medium range M:30..75% Switching point for medium speed fan
P15 Fan auto-speed low range L:1..15% Switching point for low speed fan is only applicable for 3-position
modulating control. For 2-position control, low speed fan synchronizes
with the first stage heating/cooling switch on and switch off points
P17 2-p or 3-p control selection 2-p/3-p 3-position modulation control is possible for appl. A1, A2 and A8
P18 P-band in heat mode /Switching
differential
0.5..10K Heating proportional band for 3-position modulating control or switch-
ing differential for on/off outputs
P19 P-band in cool mode /Switching
differential
0.5..10K Cooling proportional band for 3-position modulating control or switch-
ing differential for on/off outputs
P20 Integration time 0..60.0 min in
0.5 min steps
Integration time for 3-position modulating control
P21 3-p valve actuator running time 50..300s Valve actuator run time. Refer to the technical data of the actuator for
this value
P23 Ventilation in dead zone Off, H/C, C only When the temp is in dead zone, the fan can be set to run continuously.
When C only is selected, fan turns off with the heating output but con-
tinues to run after cooling output turns off
*Default values and available parameters are dependent on application selected
*Refer to application sheets for further details if required
Dimensions
Without terminal covers With terminal covers
Dimensions in mm
© 2005 Siemens Switzerland Ltd Subject to alteration