Introducing a straightforward, reliable and cost-effective solution for pump alternation control

We are excited to introduce the Carlo Gavazzi DLA series of pump alternating relays. For two to three pump systems, you don’t need to pay a fortune for controls as the DLA relays provide a simple plug and play solution to alternate pumps in a system to share the load more evenly. The DLA relays don’t need to be programmed, so can save you time and money with pump alternation setup and commissioning. 

Pump alternation is a common function used in two main scenarios: 

1) When a backup pump is required in case of main pump failure 

2) When expected flow isn’t fixed, so more than one pump may be required to work at the same time. 

The benefit of pump alternation is that it avoids one pump working all the time and therefore distributes the workload more evenly between multiple pumps in the system. If one pump works all the time, the backup pump may fail when called into action and can therefore lead to very costly downtime. To avoid this issue, the pumps are alternated at every start, so they are ready when required. 

If a pump is on continuously, the DLA relay automatically alternates after six hours to switch on another pump. The DLA also has a built-in 10 second minimum delay between each pump start-up. 

The DLA73 version comes with an independent contact trigger which can be connected for an alarm output (e.g. siren), allowing controls for the operator to notify the maintenance team in case of an issue arising. 

Key features of the range include:

  • Select from two main lines, DLA71 or DLA73
  • Alternate between two to three pumps
  • 5A SPST relay output for each pump (common contact shared) Normal, differential, and full mode options for switching pumps
    - Normal: Each pump is activated or deactivated by its own sensor
    - Differential: Each pump is activated or deactivated by two sensors. Hysteresis function
    - Full: Each pump is activated by its own sensor, however one sensor in the system deactivates all pumps
  • 35.5 mm wide DIN rail mount unit., saving space in the panel, especially in comparison to dedicated logic controllers
  • Power supply voltages: 24 & 48 VAC, 115 & 230 VAC (all galvanically separated)
  • Green LED for power ON and active pump signal
  • Built-in 10 second minimum delay between each pump start-up
  • Built-in function for automatic alternate every 6 hours in the case of no switch

You can find out more by watching the video and/or downloading the flyer.  

For more information, please get in touch with your local NHP Account Representative or email us.


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