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Lawrence Milbourn
 
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Default Mira Zest trouble


"Durn" wrote in message
...
I have an old Mira Zest 8.5kW shower which has recently stopped working.
(see http://www.mirashowers.com/onlinecat...df/p3617_1.pdf for pdf of
manual)

I dont want to buy a new/replacement shower as I will shortly (within the
next 6-9 months) be redocorating the bathroom, including a new shower.

The shower is an electric one which has 3 different "power" settings;
Cold, Medium and Hot.

If I turn the power on via the pull cord, the light on the pull cord
switches on - showing that electric is getting to the pull cord.

Now, if I turn the shower on with the power setting set to Cold, the red
light stays on. Note that the first setting, Cold, can be obtained
without electrical power (quoted from the manual).

If I now turn the shower up to either Medium or Hot the red light on the
Pull cord switches off, and I get no hot water.

Now, if I turn the water supply off and leave the electrical supply on,
the light on the pull cord always stays on, no matter what the power
setting is set to (i.e. Cold, Medium or Hot).

This leads me to believe that the Microswitches inside the shower are
working fine (otherwise I would expect the light on the pull cord to turn
off regardless of whether the water supply was on or off), and that the
fault is either the thermal switch, or the heater tank. It appears that
the fault only occurs when the shower actually attempts to heat the water
it is pulling through.

So, my question is (finally!), how can I test if the fault is in the
thermal switch, or the heater tank - bearing in mind that I am not
advanced in fault finding, but do not mind trying! Obviously, I dont want
to turn the electric and water supplies on and then stand in the shower
with the case off, trying to fault find with the multimeter... That
sounds rather stupid!

Thanks in advance,
Durn

My guess is that you've got a poor connection in your pull switch. The
loading thw heater produces is enough to cause the poor connection to drop
sufficient pd to put the neon out. Investigate the switch. It could be
just enough to tighten up the screws in it!

Lawrence