Surestop water switches are something I use in my residential buildings. I also use it for clients on residential caravans too as they are a means by which you can isolate water supply when they leave.
I had one installed yesterday (approx. 12m), because original stopcock is stiff enough to need a spanner. The customer wanted an easy means to switch cold main on and off fast for ongoing DIY tinkering, without having to increasingly stress the stopcock. So far, the customer has not reported any effect on pressure, and has had no problems with it. Works rather well. Easy like an On & Off light switch, great fun to play with.
However, I have seen and read some Surestop failure complaint on popular forums and that is what I will be discussing in the next heading.
Surestop Failures to Be Aware Of
There have been complaints that surestop switches might hammer at times. Well, this might be possible because of the way they operate. Personally, I have never had any customer complain of this.
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When it fails, there is usually a big burst pipe. Some even say that when it does nothing, you end up losing half of your scalp or the upper arm trying desperately to grapple for the now seized stoptap.
I think this might happen to the older products, but not the newer ones.