Alternation

The ISS-105 is equipped with a built-in alternator that determines which pump will start each pumping cycle.  This alternator is configured using switches ALS-0, ALS-1, ALS-2 of the Option Selector.

Table 1 describes the configuration of the alternator.

Function	ALS-0 Position 8	ALS-1 Position 9	ALS-2 Position 10
Alternation On	ON	ON	ON
Alternation On	OFF	ON	ON
Alternation On, Non-Alternating Pump Enabled	*ON	OFF	OFF
Alternation On, Non-Alternating Pump Enabled	**OFF	OFF	OFF
Alternation Off, Force Pump 1 as Lead	OFF	ON	OFF
Alternation Off, Force Pump 2 as Lead	OFF	OFF	ON
Alternation Off, Force Pump 3 as Lead	ON	ON	OFF
Alternation Off, Force Pump 4 as Lead	ON	OFF	ON

Table 1. Alternator Options

* If ALS-0 is ON in this mode, the Non-Alternating Pump will cycle when the Non-Alternating Float changes state, or after 50 cycles of the Lead Float.

** If ALS-0 is OFF the Non-Alternating Pump will cycle only when the Non-Alternating Float changes state.

Alternation On

When the alternator is on, each pump will be alternated as the Lead Pump; see Table 2.

	Cycle 1	Cycle 2	Cycle 3	Cycle 4	Cycle 5
Pump 1	Lead	Lag 3	Lag 2	Lag 1	Lead
Pump 2	Lag 1	Lead	Lag 3	Lag 2	Lag 1
Pump 3	Lag 2	Lag 1	Lead	Lag 3	Lag 2
Pump 4	Lag 3	Lag 2	Lag 1	Lead	Lag 3

Table 2.  Pump Sequence

Alternation On, Non-Alternating Pump Enabled

The Duplex, Triplex and Quadplex pump modes are equipped with an optional Non-Alternating Pump.  This pump will not be included in the normal pump alternation sequences when ALS-1 and ALS-2 (positions 9 and 10) are both OFF.  If ALS-0 (position 8) is ON, the Non-Alternating Pump will cycle when the Non-Alternating Float changes state or after every 50 cycles of the Lead Float.  If ALS-0 is OFF, the Non-Alternating Pump will only cycle if the Non-Alternating Float changes state.

The last pump in the float sequence (highest #) is the Non-Alternating Pump and can be used as either a jockey or emergency pump. 

A Jockey Pump is typically a smaller pump that will always be used first in the pump sequence.  In order to implement a jockey pump, Option Selector switches 9 and 10 must both be OFF.  The Non-Alternating Pump Float must be moved in the tank to just above the Stop Float in a Pump Down system, and to just below the Stop Float in a Pump Up system. 

An Emergency Pump is usually a larger pump that is always used last.  In order to implement an emergency pump, Option Selector switches 9 and 10 must both be OFF.  The Non-Alternating Pump is already the last pump in the sequence so there is no need to move the float. 

Alternation Off

When the alternator is off, a Lead Pump can be forced by setting ALS-0, 1 & 2 (See Table 1).  The remaining pumps will start in a sequential order as each float opens/closes.