Triton [Low pressure indicator lit]what it means

This is the most useful lamp on a Triton because it reports exactly one thing and Triton define it precisely. When the incoming water pressure drops below the minimum the shower needs to run safely, a low pressure cut-out operates. What it does is specific and it explains the symptom people describe: it switches off power to the heating elements while letting the water carry on flowing. So the experience is a shower that goes cold without stopping, with a lamp lit to tell you why.

Two things follow. The first is that this is protection rather than breakage. An element heating water that is barely moving is the scenario every safety device in this appliance exists to prevent, and cutting the heat while leaving the flow is the correct response — the water carries the residual heat away instead of sitting on the element. The second is that recovery is automatic.

Triton state that power is restored when adequate water pressure returns, so there is nothing to reset and nothing to call anyone about if the pressure comes back. That makes the diagnostic question not "how do I clear this" but "why did the pressure fall", and the answer is usually one of three: genuinely weak mains at a peak time, a restriction that has built up inside your own plumbing, or something downstream of the shower blocking the outlet. Only the first is out of your hands.

1. 1

   Note when it happens. A lamp that comes on at breakfast and never in the evening is telling you about your mains rather than about your shower.

2. 2

   Check nothing else is drawing water, then run a cold tap nearby and judge the flow. Weak everywhere means supply; strong elsewhere means a restriction on the shower feed.

3. 3

   Confirm the servicing valve on the shower’s inlet pipe is fully open. These get left part-closed after other work and it is the free fix.

4. 4

   If the cold tap is strong and the valve is open, the inlet filter is the likely restriction, and on a Triton that is a job to book rather than do. The filter is inside the unit behind the cover, Triton file cleaning it under instructions for installers and service engineers only, and the shower has to be fully recommissioned afterwards with the head off.

   Do not take the cover off to reach it. Triton’s instruction before any fault finding inside the unit is to switch off the electricity at the mains supply and remove the circuit fuse, and the recommissioning that follows a filter clean is what stops the pressure relief device bursting on the first restart.
5. 5

   If the mains is genuinely too weak, a pumped shower or a different system is the real answer. Triton’s own action for pressure below the minimum on a mains-fed unit is to check the stopvalve is fully open and, failing that, to fit a pump. No amount of cleaning raises the pressure arriving at the property.