You need a mains water feed for an electric shower. I would have thought your cold feed on your mixer will be from the cold water tank in the loft and will not have enough pressure for the elec shower, unless you have a pressurised hot water tank or a combi boiler feeding the mixer.
- Thread starter Mikey D
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Not seen one in the shower head itself but check valves are widely available and easily retrofitted.
brightspark
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as in post 21 cold feed must be at mains pressure for an electric shower . any less and it will shut down and low pressure light will come on
Kayos
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After 45 years of plumbing, you might be right, I and many others might still not understand the difference between an isolator ball valve and what it does and a check valve and the value of installing one.
If you've been a plumber for 45 years, you should know not to put a check valve on an electric shower, especially when the instructions say not to!
Luckily I got out of it after 20 years, but I feel I must bow out of this discussion because I'm clearly in the presence of a superior intellectual, who knows even more than the manufacturer
I'm not sure if yours is Swoosh or a Swish exit?
To be clear I didn't say "on" the shower I said in/on the "main cold supply feeding a shower" for the reasons I gave.
And I don't always follow manufacturing instructions.
ajlelectronics
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After 45 years of plumbing, you might be right, I and many others might still not understand the difference between an isolator ball valve and what it does and a check valve and the value of installing one.
For those who don't know the difference...
A Check valve is a non return valve, used for preventing back siphoning. An isolator valve is a tap, it is either manually on or manually off and allows servicing of a water consumer without shutting down the main feed.
Kram
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The flow is decent enough.
Two kettles - 3L would bring 10L of cold up to a comfortable 30c. 7L you would get 37c.
3 kettles and 9L cold, 40c.
Thats assuming cold is 10c which is accurate for this time of year here.
Erie Fred
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I think perhaps what @Kayos was saying was the shower unit he linked to stated in the fitting instructions not to fit a check valve, so be it.
I have fitted quite a few replacement electric showers where a check valve has been previously installed without issues or fitted new and installed a check valve, again without issue.
That said on occasions I have had to remove a check valve from a supply feeding an electric shower because it has caused issues but it's not very often.
With mixer valves/shower heads run off combies and boilers best imo to install a check valve.
