The lead pulldown time tells how long after starting the lead chiller (one time after the master chiller status has been
manually started) before checking whether to start an additional chiller. This time delay gives the lead chiller a
chance to pull down the loop temperature before starting another chiller.
If a communication failure is detected between the master and the slave then, all master/slave functions shall be
disabled and chillers shall return to standalone operations until communication is reestablished.
Note: to ensure that no compressor is started before the flow rate is correctly established then, the water flow control
is absolutely required on the lag chiller for master slave operations.
The figures below illustrate master/slave application for the most common plant layouts. Those figures are not
exhaustive.
M
A
STER
CHWS temp sensors
COOL_EWT
COOL_EWT
SLA
V
E
LOAD
SLAVE PUMP
MASTER PUMP
COOL_LWT
COOL_LWT
Typical parallel Master/slave chillers, dedicated primary pumping, variable flow
Leaving water control
M
A
STER
CHWS temp sensors
COOL_EWT
COOL_EWT
SLA
V
E
LOAD
COMMON PRIMARY PUMP
COOL_LWT
COOL_LWT
Typical parallel Master/slave chillers, common primary pumping, constant flow
Leaving water control
CARRIER SA
USER'S GUIDE FOR
30GX&HX PRO_DIALOG 4 V.2
ECG-UG-02-002
Rev: Original
Page: 54/98
©
C
ARRIER
S
.
A
NOT
TO
BE
DISCLOSED
TO
PERSONS
OUTSIDE
CARRIER
ORGANIZATION
Downloaded from
www.Manualslib.com
manuals search engine