Daikin EWYQ230DAYN [354/524] Pump control

Functional Control for a Standalone Unit ESIE06-05

2–128 Part 2 – Functional Description

3.8 Pump Control

Introduction To prevent the chiller to start up without flow, safety checks are performed.

First there is a check to make sure that water flows through the system.

If a second evaporator pump is installed a second safety check is performed: the double evaporator

pump control, in case of failure of one pump the other one takes over.

Another advantage of this control is the fact that the system switches from one pump to the other in

case failure during operation.

Pump lead/lag time The PUMPCONTROL of the user settings menu allows the user to define the pump-lead time and

pump-lag time.

Daily pump startup The user will get the choice to perform a pump start every day to prevent obstruction of the pump and

to increase its lifetime. Everyday at pump start time, which can be set in the user/pump menu, the

pump will be started automatically for a short period (5s) if the unit is off.

If dual pump control is selected by changeable digital output, then it is also possible to start up this

pump in the service/pump menu.

Dual evaporator

pump control

When dual pump control is allowed an extra digital output is needed (see Service Menu). In total four

choices will be possible: one pump (default), two pumps with automatic rotation (by running hours and

with a certain offset), priority pump 1 and priority pump 2.

When the dual evaporator pump control is set in automatic rotation, the software calculates the

differences in operation time between the two pumps. When this time exceeds the chosen offset time,

the pump will shut down and the other pump will start up, during this the unit keeps running. The

switchover will happen immediately, there is no transition time.

Remark: In case two pumps are present and the running pump fails then the unit is stopped and

started up again with the other pump. When the first pump fails a visible warning will be given. The

failed pump can not start up before this warning is reset. If the running pump fails while the other pump

is already in warning a unit alarm will be given.