Thermostatic electric shower low pressure display always on

[Johntheo5]

Would Triton still try to claim callout/admin/bs fee?

I think it would depend on what they find when they open up the unit, you could take a pragmatic approach and do nothing since the shower is working perfectly even though not the perfect answer.
I find it strange that the original switch was a different "make" to the Honeywell replacement, suggest putting this original back in and see if the power is still killed if you hang it up.
The only other explanation I can come up with is that this switch also powers a relay to supply power to both element microswitches but this would be a big departure from the normal system so unlikely IMO, you could ask them I suppose.

Have a look at your photo below and confirm or otherwise that the switch button is located where I have the arrow and that it (the button) moves in/out in the arrow direction.

 

[TryAgain1]

Yes the microswitch button is where your red arrow is

 

[Johntheo5]

I removed both brown wires from the LP microswitch (pried up both spade/terminals) and covered both terminals with electrical tape then turned on the shower to max heat (2 heating elements) the shower got to max temperature. The LP switch did not illuminate at all.

Yes the microswitch button is where your red arrow is

There might be a bit of light at the end of the tunnel with the above info, the diaphragm does not operate that LP switch, there may be a spring loaded plunger inside where the arrow is and when the start button is pressed with the switch hanging then the plunger may extend further and the diaphragm may not push up far enough to close the elements microswitches.

We know from the above that the shower is fine (and LP neon off) with both wires removed from the switch but with the switch in place. Suggest letting the switch in place, remove the two wires and join them together with a bit of wire then switch the shower on again and see if both elements are on and check the LP neon. If test OK, can concentrate on the wiring then.

 

[Alec_t]

I cant figure out how the neon microswitch is operated,

The plastic moulding which moves up under diaphragm pressure (coloured pale yellow in the pic below) has a ramped part which presses on the button.

 

[Johntheo5]

Thanks Alec_t, both photos seem to show that the ramp shape releases the button when the diaphragm rises ? so if the LP switch is NO then it opens and should have the same effect as removing the two wires which was done (with the switch in place) and the shower elements continued to heat, maybe the switch body acts as a guide for that plastic moulding and when its removed, the diaphragm doesn't move up sufficiently to close the microswitches, the test might show up something.

Under normal operation, while the element microswitches are closing, the Neon is still on which might indicate some mismatch/alignment.

Do you know/think that LP switch does more than just trigger the LP Neon?

 

[Alec_t]

the ramp shape releases the button when the diaphragm rises ? so if the LP switch is NO then it opens and should have the same effect as removing the two wires which was done (with the switch in place) and the shower elements continued to heat

That's my understanding.

Do you know/think that LP switch does more than just trigger the LP Neon?

I see no reason why it would be necessary, unless it's part of a belt-and-braces arrangement for ensuring no heat at low pressure. But that would add complication and expense which most manufacturers would want to avoid.

 

[Johntheo5]

My non thermostatic Triton T80Z 9.0kW Fastfit just has a pretty useless flag that disappears out of a little viewing slot when the pressure is OK but my previous Mira Sport had a very neat setup where the "Eco" element microswitch had 3 terminals, a common live and a NO one to the heating element and a NC one to the low pressure neon. Not only that, but when fully cold was selected, the neon was covered and not visible even if the mains pressure did fall below the minimum

 

[jj4091]

Does the pressure solenoid actuator slide clear of the switch actuator when the water is turned on or does it stay held in. It's a bit confusing when you say it's a normally closed switch

 

[Johntheo5]

Does the pressure solenoid actuator slide clear of the switch actuator when the water is turned on or does it stay held in. It's a bit confusing when you say it's a normally closed switch

Are you referring to the Mira Sport, above, combined heating element and low pressure switch with a normally open, NO, contact and a normally closed, NC contact.? or to the low pressure switch in the OP's thread?