Do I need a backflow restrictor in kitchen faucet?

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geekIT

1065 posts

Uber Geek

# 205443 13-Nov-2016 16:47

I think my kitchen faucet has been incorrectly installed. It'll run full hot and full cold but is very touchy to try and get a mix of hot and cold. (System is equal low pressure)

I'm wondering if it could need a backflow restrictor.

I'm only guessing this because I installed the bathroom faucet myself and the kit included a restrictor. It mixes without problems.

Am I right in this assumption? If so, which line does the restrictor go in?

Thanks :-)

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howienz

64 posts

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Lifetime subscriber

# 1670170 13-Nov-2016 17:32

Is the kitchen faucet suitable for equal low? Typically the tap would be unequal and would have a restrictor for the cold

geekIT

1065 posts

Uber Geek

# 1670174 13-Nov-2016 17:45

Yeah, I'm pretty sure it's an equal-low model.

But when I try and modify the flow to a mix of hot and cold, the handle is quite stiff to use.

It IS possible to get a mix of hot and cold but it takes a lot of fiddling.

Whereas the basin faucet swivels easily regardless of the temperature of the output.

I've just had a play with it. It seems to me that when switching from full hot to full cold, the hot water is being pushed back up the pipe by the cold water.

Does that make sense?

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howienz

64 posts

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Lifetime subscriber

# 1670187 13-Nov-2016 17:56

Hmm... From what you're saying you have equal pressure at the basin faucet (unless non return valves fitted). Whereas the kitchen tap appears to be receiving higher pressure on the hot side...?
Is the pressure different for h and c at kitchen faucet?
There are compact non return valves available at most plumbing merchants-you could fit one to both sides of tap assuming tap is equal low.

larknz

277 posts

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# 1670188 13-Nov-2016 18:00

Equal low pressure would be fairly unusual for the kitchen. The norm would be equal high pressure or high cold and low hot. If the former no restrictor is reqiured, however if the latter you will need a restrictor in the cold supply. If you really do have equal low pressure no restrictor is required.

howienz

64 posts

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Lifetime subscriber

# 1670191 13-Nov-2016 18:06

My mistake just reread your post - it does sound like cold is higher which is quite common, therefore unequal pressure and you'll need restrictor for cold. This would normally be integral to tap if it is unequal - what's the brand?

geekIT

1065 posts

Uber Geek

# 1670250 13-Nov-2016 19:50

Howienz: The pressure at the kitchen faucet is fairly even. Cold is slightly higher but not a great deal so, as is common in a lot of towns. We're in Otautau, around 50k n\w of Invercargill. Header tank is up in the Longwood Forest, above the town, I think. Pumped there from a bore in town.

Everyone down here has an open overhead pipe - mostly not to 7 meters, because of wind, I guess.

But being an ex-Jaffa, and an ex-builder, I wasn't going to put up with dribbling hot, so I stuck a 3.7m Apex valve on the overhead, so the pressure is now about 6.8m.

Hence the pressures being close.

Re the type of kitchen faucet - it's not immediately obvious. Probably Chinese.

And, as larknz said, it could well be High Cold and Low Hot. Lotta DIY cowboys in these parts, though. So anything's possible :-)

As I said, the faucet handle gets quite stiff when I try and mix it, but it's no BFD, really. Just another little Otautau nuisance :-)

Cheers, guys. Thanks for your input. Maybe next time I'm in Invergiggle I'll chat with Mr. Mitre10 and see if he's got a faucet that looks like mine, and if so, see if has a restrictor or non-return valve for it.

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RunningMan

5573 posts

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# 1670256 13-Nov-2016 19:59

Calling @aredwood

howienz

64 posts

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# 1670292 13-Nov-2016 20:50

Probably not the best suited tap - I've always found Methven taps work well in your type of environment.

Good luck!

Cheers

Aredwood

3885 posts

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Subscriber

# 1670295 13-Nov-2016 20:56

Since you have a vent pipe on the roof from your hot water cylinder. You definitely have low pressure hot water. There will most likely be a flow restrict or in the end of the spout. Remove it. Then install a valve in the cold pipe to the mixer. Turn on mixer with handle in center. Adjust valve on cold pipe until water is warm with handle in center.

geekIT

1065 posts

Uber Geek

# 1670409 14-Nov-2016 07:30

Thanks Aredwood. This valve in the cold line - are you referring to flow restrictor or a non-return? Or one of those on\off ball valves? BTW, there's no flow restrictor in the spout. There IS an insert, but I'd call it an aerator.

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pctek

809 posts

Ultimate Geek
Inactive user

# 1671513 15-Nov-2016 18:36

geekIT:

Yeah, I'm pretty sure it's an equal-low model.

It IS possible to get a mix of hot and cold but it takes a lot of fiddling.

It's bollocks. Get a low pressure mixer.

Aredwood

3885 posts

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Subscriber

# 1671630 16-Nov-2016 00:10

Unless it is one of these

It will be restricting the flow. And most aerators nowdays have inbuilt flow restrictors in them. Due to the water efficiency rules. As for the valve in the inlet line - I said use an on / off valve only so you can easily adjust it.

geekIT

1065 posts

Uber Geek

# 1671690 16-Nov-2016 09:06

Yeah, that looks like the spout insert. The reverse side is white plastic with a zillion holes.

Ok, you meant an on\off ball. Like this one, I guess. No probs, got a couple lying about somewhere.

Cheers :-)

Any fool can make money, but it takes a very special person to earn the respect of respectable people.