Daikin EWWQ-G - Page 44

EWWQ090G ÷ EWWQ720L - R410A - Water-cooled scroll chillers
EWLQ090G ÷ EWLQ720L - R410A - Condenser less
EWHQ100G ÷ EWHQ400G - R410A - Heat pump scroll chillers
EWAQ-G 075 - R410A - Air-cooled scroll chillers
EWAQ- - R410A - Air-cooled scroll chillers
EWYQ- - R410A - Air-cooled scroll heat pumps
Air and Water cooled scroll chillers & heat pump
Operation
Manual
Operation Manual
44
EWWQ - EWLQ - EWHQ
EWAQ - EWYQ
Air or Water cooled scroll chiller &
heat pump
D-EOMHW00107-15EN
2. A compressor can stop only if since the last start-up or shut-down of any other compressor
the Stage Dn Delay has expired.
3. A compressor can start only if since its previous start-up the Start to Start Delay has
expired
4. A compressor can start only if since its previous stop the Stop to Start Delay has expired
The unit capacity remains constant if the controlled temperature is within the interval:
[ Setpoint - Stage Up DT ÷ Setpoint + Stage Down DT ]
The following table summarize the conditions for compressors start and shut down explained
above.
Cool Mode
Heat Mode
First Compressor Start
Controlled Temperature > Setpoint + Start Up DT
Controlled Temperature < Setpoint - Start Up DT
Other Compressor Start
Controlled Temperature > Setpoint + Stage Up DT
Controlled Temperature < Setpoint - Stage Up DT
Last Compressor Off
Controlled Temperature < Setpoint - Shut Dn DT
Controlled Temperature > Setpoint - Shut Dn DT
Other Compressor Off
Controlled Temperature < Setpoint - Stage Dn DT
Controlled Temperature > Setpoint - Stage Dn DT
A qualitative example of compressors start-up sequence in cool mode operation is shown in the
graph below.