The Sequencer from Mac3 is simply a family of duty standby/duty assist relays for balancing the restarts of a twin or triple pump system. Mac3 has (as with the majority of the Mac3 line), produced a simple and effective series of units that just work (though that does make writing about them challenging!).
Alternating Pump Relays from Mac3
The Sequencer family consists of the Sequencer, Sequencer2q and Sequencer 3.
Alternating Relay for 2 Pumps
Both the Sequencer and Sequencer2q control two pumps and are available in 230/110vac and 24Vac – to suit a variety of installation sites – from commercial to domestic, even mobile installations using 24vac (boats, bowsers and the like).
Installation is simple. Sequencer units are mounted onto a DIN rail (usually in a project box – or inside a cabinet). All that needs to be considered is the working pressure of the system versus the lowest permissible system pressure. This requires the use of two pressure switches. The first is used to alternately trigger a single pump (for regular demand), with the second (set to a lower value) to trigger the second pump simultaneously (for periods of high demand).
As with all Mac3 equipment, thought has been given to dry-run protection. In this case, a dedicated float switch can be added to deactivate both pumps if the supply tank level is too low to run the system safely.
The Sequencer2q adds manual pump activation to the basic Sequencer. It combines the Sequencer2 with an additional panel that enables the user to manually override pump activation by selecting a pump (or both) to run (for testing, maintenance or the like – and of course, curiosity). The additional panel also shows the status of the attached pumps displayed via LEDs on the control board it is ideal as OEM product as it is particularly suited for use in control panel construction as it requires a mount or faceplate.
3 Pump Alternating Relay
The Sequencer 3 is a slightly different animal. It is capable of working with three pumps (rather than the two in the other Sequencer models).
Unlike the Sequencer2q, the Sequencer 3 has the current pump status and manual pump control LED display integrated into the main body of the unit. It is therefore ideal for mounting inside a clear-fronted cabinet or control box (I mean, who doesn’t like to see what’s actually going on?).
As with the other models in the Sequencer family, the Sequencer 3 uses the same pressure switch setup for pump activation (alternated single unit start, and multiple pump startup as required), along with the potential to add a float switch for dry-run protection.
However, unlike the other models, the Sequencer 3 is only available in 230/110vac.
Summary
All in all, the Sequencer family of pump alternating relays are simple to install, and even easier to use. From a simple two-pump installation that doesn’t require manual override (Sequencer) to two or three pump systems that can display pump activity and allow manual pump activation (Sequencer2q or Sequencer 3), there is a Mac3 Sequencer to do the job.
Other uses for the Sequencers
Now usually, I stick only to the water related uses of Mac3 equipment, but the Sequencer family can very easily be deployed with pneumatic systems so long as there are multiple compressors/motors attached to the system. In fact, now that I think about it, perhaps I should be writing about ‘alternate’ uses for some of these units… Watch this space! (or if you’d like to know more, contact us to discuss).
For more information
Contact Jim, our Mac3 Technical lead. Jim and Tom have over 25 years of experience in Water Control Systems.
