Dwyer MPCJR - Manual (Page 12)

Lead/Lag Operation
The Mercoid ® MPCJR pump controller is designed to easily operate a pair of pumps
in the most efficient manner possible. The controller has a 'lead/lag' feature that
allows two pumps to operate in an alternating fashion to minimize wear.
The Mercoid ® MPCJR pump controller has a pair of set points each for pump 1 and
pump 2. If the lead/lag feature is turned off, SP1H and SP1L control pump 1 and SP2H
and SP2L control pump 2. If the lead/lag feature is turned on, pumps 1 and 2 will be
controlled in the alternating fashion described below. In all cases the P1 lamp will
indicate activity of pump 1 and the P2 lamp will indicate activity of pump 2. The
lead/lag operation is set in the Secure menu with the item LdLg.
Lead/Lag On
After installation, set the SP1H to the high level (pump on point) for standard
operation. Set SP1Lto the low level (pump off point). Set the SP2H to the level where
you want BOTH pumps to turn on (emergency pump on). Set the SP2L to the level
where you want the second pump to turn off (emergency pump off).
The controller will not allow you to set SP1H below SP1L, SP1L above SP1H, SP2H
below SP2L, or SP2L above SP2H. The controller will not allow you to set any set
point or alarm point above or below the programmed scale. No error messages are
generated. The displayed value will stop at an allowable point just above (or below,
as the case may be) the maximum or minimum allowed.
In normal operation, when the SP1H point is reached, one of the pumps will turn on.
When lead/lag is turned on, pumps 1 and 2 will alternate. If the level reaches the
SP2H point, both pumps will be turned on until the SP2L point is reached, where one
of the pumps will turn off. When SP1L is reached, remaining running pump will turn
off. The last pump off will not be the next pump on.
Lead/Lag Off
If lead/lag is turned off, SP1H and SP1L control pump 1 and SP2H and SP2L control
pump 2. There is no alternating function.
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