ZONE GUARDIAN Test Module continuous improvement

Jenni RoseLatest News Leave a Comment

Part of our ethos at SEP has always been, and will continue to be, to listen to customer feedback and improve our products.

One such recent and very important example is that of the Test Module for our flagship ZONE GUARDIAN flow switch test device…

As nothing stands still, we needed a design change to make the ZG test modules easier and quicker to manufacture (we just couldn’t get enough of them based on the original design; so our supplier can now keep up with our growing demand), improve robustness and solve a couple of niggles. The new modules have been approved by the LPCB, and are already being supplied with our ZONE GUARDIANS.

The changes

You can see the changes made to the ZONE GUARDIAN test modules by reviewing these photos.

Front of the original ZG test module

Front of the new ZG test module








Inside of the original ZG test module

Inside of the new ZG test module








The ‘cleanliness’ and simplicity are evident; what may not be immediately evident are the following user improvements:

  • More room for wiring, along with an easier and more modern methodology using Wago cage clamps;
  • Replacement of wiring ‘loom’ with multi-core cable, reducing risk of installation damage;
  • For now at least, we are also supplying a free Wago tool along with a simple instruction for us;
  • Keyed-alike switch with two keys supplied;
  • PCBs + 1 multi-core cable make for simple replacement of parts if either become faulty in future.


We first agreed with our supplier that a certain type of (keyed-alike) switch would be used; however, during early testing, the quality and look of this switch was not to our liking.

We then agreed that a high-security switch would be used, which has 25 possible combinations (‘001’ to ‘025’ being etched on both the key and the barrel face)

Although we had excellent feedback on usability and ease of installation (not without the odd niggle, we’ll be honest), the original design was not sustainable at the high volumes we now require and, being frank, it didn’t look as slick as we’d like.

Moving forwards

Our supplier was proactive in suggesting ways, with investment, that production could be streamlined at the same time that an improved product could be delivered for the same cost. We hope you like the results.

At the same time, taking the valued feedback from our customers into account, we have determined that the ‘high security multi-combination key’ is not (in the majority of cases) desirable. Therefore, we also decided to update the keyswitch to a model which is keyed-alike.

The new module will be shipped with all ZONE GUARDIAN units imminently.

If customers have any further questions then these should be addressed directly to Rob Bell. Call +44 161 428 1180 or email


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