Water Pressure

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#805476 25-Apr-2013 15:36

What I would recommend? Ideally I need to know more information first. But try to find that valve inside the wall that the developer is talking about. It could well be the problem. It may simply be a "3 in 1 valve" (isolating tap, line strainer and one way valve combined). Or it could be a pressure limiting valve. When pressure limiting valves fail they often cause low water pressure / flow issues. Also there is a brand of limiting valve that comes preset to 300kpA outlet pressure and is cheap so you might have one of them installed.

If you manage to find it post a photo of it.

As for the pressure drop test, connect a pressure gauge to the hose tap closest to the front of the house. Turn on another tap. (Or better yet the shower) And see what the pressure drops down to.

What will make a big difference to the costs to fix is. Do you want all 3 showers to have good flow and pressure at the same time? Or is only having just 1 shower at a time with good pressure / flow ok? And do you want to be able to turn on other taps in the house while someone is in the shower without affecting them?

As for the developer installing 25mm OD pipe (20mm ID) This is just considered standard practice now. (25mm OD might even be cheaper than 20mm OD anyway). And 25mm OD is the min required size in Australia. Despite them being far more concerned with saving water than here.

Larger that usual would be installing 32mm OD (25mm ID) pipe. I have this on my own house even though my incoming pressure is between 610 and 700kpA. But since Im a Plumber and Gasfitter almost everything plumbing related in my house is oversized.

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#807464 29-Apr-2013 15:27

Hi There!

I called Water care. They say that according to their notes we are getting 1200KPA which is 5x their minimum and thought that was good, and they noted I had 20mm pipes and meter which is better than is normally supplied. They had no point of reference for what L per Minute is at the street, but the minimum is 25L/M.

I made a mistake about our external water heater. It's actually a Rinnai rather than Rheem and is a 24, but has a sticker saying rated 15L/m.

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#807873 30-Apr-2013 09:38

Ok I have done the flow rate tests. Essentially with our current setup we get 9.0L/M with the shower head on, 10.5 with it off. Watercare state minimum 25L/M so something must be limiting the shower somehow? I checked and made sure all other taps were off and no washing machines or dishwashers going.

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#807883 30-Apr-2013 10:00

Was your Hot water system installed when the house was built or is it a retro fit? if the later you may have an incompatible shower mixing valve. With the Infinity type hot water systems you need a mixer for Equal pressure systems and rated for your mains pressure. In some retro fits they will leave the shower valve and just add flow restrictors as an easy way out but less than ideal.

We had similar issues in our home, we changed the shower valve and presto fixed, except for one annoying habit as the hot water flow heats the flow from the boiler drops especially noticeable in the Kitchen which is the furthest point from the boiler, a feature we just have to live with.

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#807884 30-Apr-2013 10:02

KiwiNZ: Was your Hot water system installed when the house was built or is it a retro fit? if the later you may have an incompatible shower mixing valve. With the Infinity type hot water systems you need a mixer for Equal pressure systems and rated for your mains pressure. In some retro fits they will leave the shower valve and just add flow restrictors as an easy way out but less than ideal.

The house is 5 years old, and the Rinaii was installed when the house was new.

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#807943 30-Apr-2013 12:07

networkn: Ok I have done the flow rate tests. Essentially with our current setup we get 9.0L/M with the shower head on, 10.5 with it off. Watercare state minimum 25L/M so something must be limiting the shower somehow? I checked and made sure all other taps were off and no washing machines or dishwashers going.

Where did you measure the flow rate?

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#807944 30-Apr-2013 12:09

Technofreak:
networkn: Ok I have done the flow rate tests. Essentially with our current setup we get 9.0L/M with the shower head on, 10.5 with it off. Watercare state minimum 25L/M so something must be limiting the shower somehow? I checked and made sure all other taps were off and no washing machines or dishwashers going.

Where did you measure the flow rate?

From the 3 showers in the house all got the same (I didn't run all three at the same time, as this isn't a situation that would occur in our household.

Also to note that there was no flow difference between full hot and full cold.

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#807957 30-Apr-2013 12:48

networkn: Ok I have done the flow rate tests. Essentially with our current setup we get 9.0L/M with the shower head on, 10.5 with it off. Watercare state minimum 25L/M so something must be limiting the shower somehow? I checked and made sure all other taps were off and no washing machines or dishwashers going.
...
Also to note that there was no flow difference between full hot and full cold.

OK, so this means that a flow restrictor is fitted to the cold water pipe, either inside the shower mixer, or just behind it, most likely inside the wall. They sometimes do this for a house with low-pressure hot water to equalise the pressures coming into the mixer (hot vs. cold) and allow the mixer to operate more smoothly. Otherwise, you end up with nothing happening through most of its range, and then suddenly going from luke-warm to very hot right at the end of the rotation.

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#807960 30-Apr-2013 12:56

grant_k:
networkn: Ok I have done the flow rate tests. Essentially with our current setup we get 9.0L/M with the shower head on, 10.5 with it off. Watercare state minimum 25L/M so something must be limiting the shower somehow? I checked and made sure all other taps were off and no washing machines or dishwashers going.
...
Also to note that there was no flow difference between full hot and full cold.

OK, so this means that a flow restrictor is fitted to the cold water pipe, either inside the shower mixer, or just behind it, most likely inside the wall. They sometimes do this for a house with low-pressure hot water to equalise the pressures coming into the mixer (hot vs. cold) and allow the mixer to operate more smoothly. Otherwise, you end up with nothing happening through most of its range, and then suddenly going from luke-warm to very hot right at the end of the rotation.

Woohoo! Progress. So the dumb question now is... How to fix that so I can get better shower pressure?

Do I need to get a plumber to dismantle the shower fittings to check?

grant_k

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#807963 30-Apr-2013 13:16

networkn:
grant_k:
networkn: Ok I have done the flow rate tests. Essentially with our current setup we get 9.0L/M with the shower head on, 10.5 with it off. Watercare state minimum 25L/M so something must be limiting the shower somehow? I checked and made sure all other taps were off and no washing machines or dishwashers going.
...
Also to note that there was no flow difference between full hot and full cold.

OK, so this means that a flow restrictor is fitted to the cold water pipe, either inside the shower mixer, or just behind it, most likely inside the wall. They sometimes do this for a house with low-pressure hot water to equalise the pressures coming into the mixer (hot vs. cold) and allow the mixer to operate more smoothly. Otherwise, you end up with nothing happening through most of its range, and then suddenly going from luke-warm to very hot right at the end of the rotation.

Woohoo! Progress. So the dumb question now is... How to fix that so I can get better shower pressure?

Do I need to get a plumber to dismantle the shower fittings to check?

It's not hard to do it yourself if you're a bit handy with tools and thread tape to seal it up again afterwards. That is, assuming the flow restrictor is inside the mixer, which it frequently is. But if per chance they have put it inside the wall, then that is most likely plumber territory unless you are exceptionally keen to get your hands dirty.

You may find that the whole mixer will need to be replaced, as it may be designed for unequal pressures, and therefore not usable with the setup you have.

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#807965 30-Apr-2013 13:18

grant_k:
networkn:
grant_k:
networkn: Ok I have done the flow rate tests. Essentially with our current setup we get 9.0L/M with the shower head on, 10.5 with it off. Watercare state minimum 25L/M so something must be limiting the shower somehow? I checked and made sure all other taps were off and no washing machines or dishwashers going.
...
Also to note that there was no flow difference between full hot and full cold.

OK, so this means that a flow restrictor is fitted to the cold water pipe, either inside the shower mixer, or just behind it, most likely inside the wall. They sometimes do this for a house with low-pressure hot water to equalise the pressures coming into the mixer (hot vs. cold) and allow the mixer to operate more smoothly. Otherwise, you end up with nothing happening through most of its range, and then suddenly going from luke-warm to very hot right at the end of the rotation.

Woohoo! Progress. So the dumb question now is... How to fix that so I can get better shower pressure?

Do I need to get a plumber to dismantle the shower fittings to check?

It's not hard to do it yourself if you're a bit handy with tools and thread tape to seal it up again afterwards. That is, assuming the flow restrictor is inside the mixer, which it frequently is. But if per chance they have put it inside the wall, then that is most likely plumber territory unless you are exceptionally keen to get your hands dirty.

You may find that the whole mixer will need to be replaced, as it may be designed for unequal pressures, and therefore not usable with the setup you have.

I think for the $100 I'd get a plumber in and make sure I didn't cause a problem. Thanks for the advice I'll make the call and see what happens. Anyone know a great plumber in Auckland? Our ones didn't seem that interested.

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#808061 30-Apr-2013 15:48

One more question for the time being, what is the ideal Litre/M for a great shower?

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#808169 30-Apr-2013 18:32

networkn: One more question for the time being, what is the ideal Litre/M for a great shower?

Grohe make a range of good quality shower heads and this is what they have to say on the subject:

WELL (Water Efficiency Label) is a product classification system of the European sanitary valve industry.
WELL was established to promote responsible water usage and to provide an easy-to understand evaluation system for consumers and professionals.

For showers, the WELL assessment category is the water efficiency. A** rated showers have a controlled flow rate between 4.5L and 9L per minute.

A quick Google search found references from 16 Litres per minute for standard shower heads, all the way up to 30 Litres per minute!

I seem to remember a figure of 9L per minute being bandied around when the Labour Govt. tried to make water-saving shower heads mandatory. With a well-designed head, 9L should probably be enough. We get by with even less than that on our farm where the water is gravity fed. You get used to it, but it is sometimes nice to have a shower at someone else's place where they have mains-pressure hot water and enjoy the sheer luxury of being water-blasted.

P.S. Thinking back to when I last tweaked the shower mixer we have here I remember there being two plastic knobs coloured red and blue behind the face plate of the old Feltonmix. If you can figure out how to remove the faceplate of your mixer, you might just find something similar. Or you might not, in which case they will have probably used a plastic or brass insert in the cold water inlet, or they could have used a small valve before the mixer. We had these on the handbasin at our last house, to stop water spraying everywhere if somebody accidentally opened the faucet too far. They were a chromed hexagonal-shaped block of metal about 50mm long with an adjuster screw in the middle. By turning the screw a small amount, we could reduce the flow to a sensible level.

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#808238 30-Apr-2013 20:36

networkn: Ok I have done the flow rate tests. Essentially with our current setup we get 9.0L/M with the shower head on, 10.5 with it off. Watercare state minimum 25L/M so something must be limiting the shower somehow? I checked and made sure all other taps were off and no washing machines or dishwashers going.

Looks like some good answers but you need to check flow at your taps to complete the analysis. If you had to pick just one, laundry tub will be most convenient, but ideally you want to know in the bathrooms near at least one shower as well.

Aredwood

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#808303 30-Apr-2013 23:06

You need to do the test I suggested earlier. The one where you turn your shower on and measure the water pressure at the same time. This test will tell you if the problem is caused by something affecting the whole house such as a failed pressure limiting valve or if it is a fault on your shower.

Also are your showers the type with a flexible hose? (slide shower). Sometimes these can fail and cause poor flow. Check the flow rate directly from the wall outlet. Have a look into the wall outlet. Sometimes there is a flow restrictor there.

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