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
EWWQ - EWLQ - EWHQ
EWAQ - EWYQ
Air or Water cooled scroll chiller &
heat pump
D-EOMHW00107-15EN
The MS function is able to manage individually several plants. The main difference that identifies
every plant type is mainly in the number and in the connection method of the water pumps. The
MS never can provide a speed modulation signal for one or more water pumps.
- Plant 1 : Single Common Pump
The simplest plant that Master Slave function can manage is composed by a single common
pump installed on the water manifold that provided the water flow for all chillers of the network. The
pump enable is obtained putting in parallel the enable contacts of the evaporator water pump of
each chiller. First chiller enabled to start by the Master will activate the common pump. With this
plant type all chillers are always crossed by the water flow even if they are still.
- Plant 2 : Single Chiller Pump
In the second plant type every chiller of the Master Slave network is equipped with a pump. The
pump can be installed directly on the unit or in the pipe of the single chiller and it avoids the water
flow in the evaporator if the chiller is in off state. Every pump will be commanded only by the
chiller to which is connected.
- Plant 3 : Double Chiller Pump
Third plant type is an extension of the previous plant. As standard every chiller can control two
evaporator water pumps: primary and standby. This function is maintained also in Master Slave.
Every pair of pumps is connected to the related chiller that will manage them rotation according to
the local settings.
- Plant 4. Chiller with sectioned evaporator
In the last plant type every chiller has the evaporator sectioned by a two way valve that avoids the
water flowing if the chiller is not running. The number of pumps and valves has to be the same of
number of chillers, as every pump and every valve is associated to a specific chiller. Like in the
Single Chiller Pump plant every chiller will enable its valve and its pump. No standby pump can be
managed in this plant type.
In this case it is advisable to connect the evaporator water pump enable provided by the chiller to
the valve and consequently the feedback of total opening of the valve to the enable of the pump. In
this way should be avoided all problems of over-pressure due to a simultaneous starting of the
pump and of the valve.
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