Water imbalance
Water imbalance.
Or
Why is my shower only giving warm water or low pressure?
What Does Water Pressure Mean?
Water pressure is a measure of the force of the water moving through your pipes. Water pressure is measured in bars, with 1 bar being the force needed to raise water to a height of 10 metres. Showers are rated with a minimum required pressure rating, typically between 1.5 to 2.5 bar.
Where Does Water Pressure Originate?
Water will enter your house at the cold mains under pressure, i.e. at 'high pressure'. If you have a combi boiler, this will then heat this water, and retain much of its original pressure, meaning a good flow. If you have a gravity system, the pressure from the mains will be lost and the pressure to your shower will come from the force of gravity moving the water downwards from your water tank.
There are other water systems, other than gravity and combination boiler. For example, in new builds and for large houses it is common to see what is called an 'unvented', or 'megaflo' system. In this case, water is still stored in a tank, but it is stored in a pressurised environment, so it doesn't rely on gravity to create any motion.
Gravity Fed Heating Systems
A gravity system is a low-pressure system with a cold water storage tank (usually located in the loft) as well as a hot water cylinder. As the name suggests, the pressure supplied around your household is based upon the height in which the cold storage tank sits from the location of the shower. So, in gravity systems, every 1-metre drop from the water tank typically equates to around 0.1 Bar in pressure.
So upstairs bathroom taps and showers will normally be around 2 metres below your tank, resulting in a water pressure of 0.2 Bar, a value too low to be of usefulness with modern appliances.
Options:
- If you want a 'good' shower, you will be disappointed but for a few hundred pounds install a duel flow (both hot and cold feed) 2.5 bar pump, which would mean you suddenly have a much wider range of options when it comes to all future purchases and a great shower with both static water temperature and flow.
Combi-Boilers
A combination boiler is typically installed in your kitchen at the point in which the pressurised cold mains water enters your property. It manages both your hot and cold water supplies as well as your central heating, giving it the name ‘combination’.
The combi-boiler system heats cold water directly from the mains supply as and when it’s needed when the hot tap is turned on. As the water supply comes from the mains, at mains pressure, your water will be of a high pressure and suitable for a large majority of high-pressure showers provided you have a fairly good combi boiler. Pressures can vary from boiler to boiler, but the typical pressure expectation from a combi-boiler is somewhere between 1.5 and 2.5 Bar. Tap & Shower
Options
- If you have a combination boiler, and it is relatively modern, it will supply your pressures as required. Generally, this is around 1.5 – 2.5 bar, although it can sometimes be more. The majority of showers operate perfectly with this kind of pressure. Insignia Showers are actually designed for this method of heating and flow. Although rare, you may need to balance pressures.
Unvented Water System
With an unvented water system (sometimes referred to as a Megaflo system), a main cylinder will be filled with cold water directly from the mains. Unlike a traditional gravity system, an unvented system does not require additional storage tanks and instead offers a much more simple solution. The water held in the main cylinder is kept constantly under pressure by incoming mains water and then heated indirectly from an external source such as a boiler, solar panel, oil or electricity.
Options
- If you have an unvented water system, you can have any shower and accessories you want - body jets, big rain heads, 2 or 3 outlets on at the same time. You may need to balance pressures.
Always remember that this is just a guide. There are many other factors, such as the direction and bends of the pipework or the size of those pipes, which can affect water pressure.
If you are unsure about what water pressure you have, it’s always best to have your plumber take a look and let you know before you purchase. A plumber will have a pressure gauge tool to work out exactly what pressure you have in your home, giving a much better idea of suitability
As an example, installing a high-pressure bath filler in a low-pressure system would mean that it would take ages for the bath to be filled, and since the water would be constantly cooling you would have to use more hot water to compensate. Subsequently, a shower will never give its full potential and body jets or overhead shower may be reduced to a dribble.
FAQs
Something is wrong with our shower, water only dribbles out of the overhead shower head and nothing out of the body jets.
Answer: We are not a plumbing company, but we are probably the UK's leading experts on shower cabins as we design, build and manufacture. This means we really know our onions; it can be assumed more so than any tradesman as to what is required to get the perfect shower. At the beginning of all build instructions detail on requirements to operate a shower to full capacity is given. For example, 2.5 bar combined required. Your tradesman should check at this point by using a simple pressure testing tool. You have the recommended figures then the shower will work perfectly. If incorrect and under pressured, it will not.
Remedy: Get your plumber to uprate the pressure by using a suitable pump
I am very annoyed I paid a lot of money for my shower and the water only gets warm then goes cold. I had a “professional plumber” install this and he says your shower is faulty!
Answer: Your “professional plumber” has not checked equal pressures before installing as they should. The answer lies in the cold feed having more pressure than the hot feed. As the shower water tap is opened the water feeds meet. The cold water is pushing your hot backwards so at best water is only warm.
Remedy: Rebalance your water supply. Firstly, check the house connections to the shower. The water valve is marked with blue and red dots. Frequently we have seen these water supply connections fitted the wrong way around.
Blue = Cold
Red = Hot
Shower valves have a slightly smaller bore on cold, wrong way round = warm or cold water only.
UNDERSTANDING WHY MY SHOWER DOESN'T GET HOT OR FLUCTUATES
Were they correct?
If NO, change to correct positions
If YES, then the hot feed has an imbalance with cold. There are two ways to usually cure this:
- The preferred way. Your installer will know this most probably. He can purchase a plumbing accessory know as a PEV (Pressure Equalising Valve). These are simple to fit and connect inline on the water supply hoses. You water will now be balanced and the shower will operate as it should.
PEV valve
- Your installer should have fitted water shut-off valves to your water supply pipes. A temporary check on the water balance can be done by very slowly turning the screw on the cold feed to restrict flow by a very small amount. This can be used as a yardstick as to the problem
Water shut-off valves.
I was told by your technical department the fault I have with pressure and not getting hot was not the fault of the shower. How can you know this without checking it yourself? Surely all things can fail! I think they were wrong.
Answer: If the fault presents itself from installation or soon after, it will be your water pressures. The shower water valve is very simple in design. Water comes in on the left and right. In the middle is just a hole, water goes into. This cannot fail. A thermostat cartridge inside the valve can fail but only through limescale or foreign matter and the time between installation and reporting is too short to cause this. Signs of the thermostat failing are it can no longer be adjusted as seized up.
I have owned my shower for several years and the water suddenly and progressively got colder and colder, also hard to adjust. What could be the problem?
Answer: Your thermostatic cartridge has failed due to Limescale and requires replacement. Please see Insignia's range of “How To” videos showing detailed easy replacement.
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