Can you get 'low pressure' Check Valves?

[jon.p.weaver]

Last week I posted a question as to why my Ikea taps came with Check Valves of which I got many helpful answers.

Because of unforeseen problems, I had to install them temporarily using 'flexible hoses' and I didn't bother to put the check valves in for now. On face value, everything was OK.. I figured that the valves was purely a legal requirement after all and there was no technical reason why they had to be there..

That was until last night...

The taps I have bought have a 'rinser' attachment, in the form of a 2 foot hose, held up in the air by a spring.. Water is directed out of the tap, or up to the rincer using a leverl on the tap, and the 'rinser' attachment is operated using a level on the handle which presses a valve..

So to use the rinser you have to do 3 things.

1. Turn the level to direct water upto the rinser
2. Turn on the tap
3. Press the lever on the rinser

Last night, I had the taps in the mixed position and turned the lever to direct the water to the rinser.. When I did this, there was a whosh as the water entered the pipes, but it didn't stop. It simply sounded like water running through pipes just like you get when you normally run the hot/cold water.. When I put the mixer to full hot or full cold, it stopped.. But when it was mixing, you could hear running water. The problem was obvious.. Because the output of the rincer is blocked (by the valve), it holds the water back, but since the tap is open, water is entering the tap body and mixing.. In my case, the cold is high pressure mains and the hot low pressure and what I could hear was the cold water pushing up the hot pipes...Not good at all!!

So clearly I need to put the check valves in, not only because of the legal requirements, but also to stop my from flooding the house!

The big problem I have in my house is low hot water pressure.. Right now, with the flexible pipes in, the hot has been reduced to a trickle and I hope that this is caused by a kink in the pipe and when I install it permanently (using solder joints) it will be better..

Looking at the valves I have now, they seems quite stiff.. I have a fear that it will restrict the pressure and make the flow worse than it is now... I just wondered if you can get a check valve which is 'loose' and has little effect on the pressure of the water?

Does anything like this exist? Do check valves come in different 'strengths'?

Jon

[Ben Willcox]

Yes I had a similar problem, and I simply removed the springs out of the check valve and then had no problems! They still work although perhaps in this mode allow a tiny bit of extra water back before closing, but I don't think it really matters in this application.

Cheers, Ben

[John Rumm]

Ah...

Yup, that would be the technical reason! ;-)

Alas I expect probably not. You have a tap that is designed to work on a high pressure hot system - these often perform poorly on gravity fed hot water systems.

It will reduce it - the question is how much. If you are particularly unlucky it will prevent the flow of hot!

Not really... although some brands may be less aggressive than others. you can butcher a double check valve to remove half the valve (i.e. making it a single check valve!) - it would no longer be legal, but ought to peform the technical part of the job.

You may need to fit a pump to get adequate performance with that tap.

[John Stumbles]

You may have to hunt around to find regular single-check valves you can readily do this with: some have the gubbins held in with C-rings which are nigh impossible to remove, others have rings where a little bit of the metal is distorted inwards so you can get a grip on it to remove it.

Alternatively single-check valves for showers are quite light in action. They have 1/2" BSP male[1] one end, female the other, so may be easy to retrofit into an existing installation.

[1] on my gas retraining last week I was told (I don't know if the teller had his tongue in his cheek) that we're not supposed to refer to threads as male and female any more, but as external and internal. All together now: Political Correctness Gone Mad!

[Andrew Gabriel]

One computer company I worked for some time back, we had a work experience teenager come and work for some weeks. He did things related to building and installing/moving PCs around the office.

One day, when holding a cable connector, he said "I never can remember which is a male and which is a female connector". There followed a short lesson on the birds and the bees, much to his embarrassment. He never lived that one down...