Redring [ot] fault codewhat it means and how to fix it

Both generations of the Selectronic use these two letters, though they show them differently. On the Selectronic Premier the single-digit display flashes a lowercase o and then a t in turn, with eight short bleeps; on the Selectronic Advanced the display reads ot and the Start/Stop button flashes rapidly. Redring’s heading for it is Over Temperature Shutdown, and their description is that an abnormal condition has caused the water to get too hot, so the unit has shut down straight away and stopped the water, to prevent any hot water coming out of the handset.

The display keeps showing it until the water inside is back at a safe temperature, and only then does the shower switch itself off and allow a normal restart. The cause Redring name first is the one you can fix at once: switching the shower off at the ceiling isolator instead of the Start/Stop button. Pressing Stop runs the water on for a few seconds to cool the heat exchanger for the next shower; killing the power skips that, leaves hot water sitting on the elements, and the next start can trip the shutdown before you have touched a button.

Behind that sit the reasons a shower genuinely overheats, all of them a restriction on flow: a scaled handset, a blocked inlet filter, a mains supply that has dropped while the shower was running, or a failing outlet sensor reading hotter than the water. Redring also fit a two-stage mechanical thermal cut-out above the heat exchanger that works independently of the electronics. Stage one clicks off and resets when cold water is run through; stage two, for an extreme temperature, switches off permanently and has to be replaced, and Redring’s instruction is that if ot persists after purging you contact them.

1. 1

   Purge the hot water. On the Premier, while o and t are flashing, hold the Cooler button for more than three seconds; water runs only while it is held. On the Advanced, with the shower off, hold + and − together for two seconds and let cold water run for about a minute.

   Redring print this in capitals: the water will be hot. Stand clear of the handset spray while purging and point it into the tray.
2. 2

   Wait for the shower to switch itself off, three short bleeps on the Premier, then restart with the Start/Stop button in the normal way.

3. 3

   From now on always stop the shower with the Start/Stop button and let it run its cool-down before you touch the isolator. Redring name the isolator habit as a cause of this shutdown.

4. 4

   Clean the handset: rub the rubber nozzles and soak the spray plate in limescale remover, and check the hose is not kinked or blocked. A restricted outlet is the usual way a shower gets too hot.

5. 5

   If ot returns on a clean handset with a good mains supply, stop. Redring’s instruction for a persistent ot after purging is to contact them, and the parts involved, the inlet filter, the outlet sensor and the thermal cut-out, are all behind the cover.