Holdback is a safety feature that "reserves" a specific portion of your carrier (water). The Mixmate system monitors your progress and closes the main carrier valve when the user-defined holdback value is reached.
The Purpose: To ensure enough carrier remains at the end of the mix to:
Flush the main lines and pump to the final destination.
Rinse jugs in the inductor.
Execute all defined product rinse amounts.
The Logic: If the system reaches your "Minimum Holdback" limit while products are still being added, carrier flow will pause until the products are finished.
The Result: You avoid a "dry pipe" scenario where the mix is finished, but the lines are still full of chemical.
Important Note: Defining too small of a holdback value does not guarantee a full system flush and can cause an "overrun" of your mix size due to excessive rinsing.
To find your ideal holdback setting, add up:
Main Line Volume: Estimated volume to flush to the destination.
Inductor Rinse: Volume needed for jug/tank rinsing.
Product Rinses: Total of all programmed rinse amounts.
The "Ratio" Rule:
Large Carrier %: Requires a smaller percentage of the total for holdback.
Small Carrier %: Requires a larger percentage of the total for holdback.
What does the partial valve postion do for you? This setting allows the operator to balance Carrier Flow Speed and Product Flow Speed.
Partial Valve Setting (Default 50): This is the target opening percentage for the carrier valve while products are moving. 50% usually allows high flow while maintaining a strong vacuum to pull product through the inductor.
Suction Priority: If product induction is slow, set the Partial Valve Position lower (toward 20) to increase vacuum. Likewise, if product induction is too fast, set the Partial Valve Position higher (toward maximum pump capacity) to decrease vacuum.
Flow Balancing: Prevents the carrier from "outrunning" the chemical induction, protecting your holdback reserve.
Automatic Throttling: The system dynamically adjusts the valve between a Minimum of 20 (ensuring some carrier is always moving) and the Maximum Valve Position identified while running your Carrier Pump Profiling wizard.
Automated Flow Balancing: Optimizes the Suction Priority and Flow Balancing to protect your holdback reserve, and prevent pump surging or cavatation.
Start: Mixmate runs carrier and products simultaneously.
Monitor: Constantly compares Total Carrier Remaining vs. Minimum Holdback.
Pause: If the two numbers match, the carrier valve closes while products finish.
Finish: Once products are 100% done, the carrier valve re-opens to use the "Holdback" water for the final rinse and flush.