On topic post- Electric Shower, quick flick of switch OK, normal switching on Low pressure and cold

[Jimk]

Flow switch?

[misterroy]

Hi, my 20 year old Mira shower works fine if I flick the rotary switch as fast as I can, but if I turn it on at a normal speed the water pressure is not enough and the heater does not turn on. I can see the difference at the shower head quite plainly. I am in a soft-water area. The pressure seems ok at the taps. Is it likely to be the bit that measures the pressure that is failing and adding extra resistance to the flow?

[misterroy]

At £45 for a new one, I might be better buying a new shower. Here is a picture of the valve

it be worth taking it to bits for an inspection and clean?

[Harry Bloomfield, Esq.]

misterroy explained :

Might be the micro-switch not clicking over fully, when water is turned on gently - easy to check, cheap to replace and a simple fix.

[Tricky Dicky]

A lot of these switching on problems and low pressure lights coming on are down to a clogged up inlet filter, that is certainly the case on our Triton TX100. If as you say you have had your Mira shower 20+ years it might be overdue a clean out they are usually a fine mesh that is easily cleaned and does not need replacing.

Richard

[Brian Reay]

They normally have a pressure/flow switch and an over temperature cut out. It could be either. Sometimes scaling is the problem- it reduces flow.

[misterroy]

I have switched it on with the cover off, the hand switch puts the lever that knocks the switch 2/3 of the way there, when the pressure is detected it then makes the rest of the rotation.

[John Kenyon]

And while you are at it, replace the clamps which hold the incoming and outgoing pipework onto the pilot valve. (Part number 419.82)

The inlet clamp on my Mira Sport failed in the middle of the night resulting in mains pressure water everywhere.

The pilot valve got replaced a few years before that - symptoms were a vibrating noise and partial opening of the pilot valve. The temporary fix was to turn on the shower and then close and reopen the isolating valve feeding the shower, permanent fix was replacing the pilot valve.