Problems with Rainbird ESP RZX on Bores

I have installed a lot of these controllers this year and only recently had a couple of problems with them when used on bore systems.

It seems that the smaller transformer in them may not have sufficient capacity to cope with the demands of a pump start relay and a solenoid at the same time. The controller either brings up an ‘MV err’ message immediately or runs for a short time and then cuts out. Its been tricky to diagnose the exact problem but in discussion with Shaye from Rainbird it seems that the transformer may be the source of the problem.

The controllers have worked perfectly on mains water supply systems but I hesitate to use them on bores now and would go with the Hunter X Core which has a larger transformer. Its worth knowing in case you are having similar problems!


3 thoughts on “Problems with Rainbird ESP RZX on Bores

  1. I am also facing same issue with this controller installed last week with bore water and turning off after 3-4 mins with error no ac

  2. I too am having this issue, however slightly different.

    I have programmed my Zone 1 to come on at 5am. Then again for 7pm. Both for 15mins. The 5am time works perfectly, when the 7pm time comes, i get the “no AC” error.

    When i try the manual option, the pump relay/contact opens and closes really fast. or makes a fairly angry grinding sound.

    My esp has been hard wired in, as my previous electro mech controller was hardwired in.

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