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How to use the Redring Powerstream Instantaneous water heater to provide hot water in your home without the need for a central heated tank.

Everything you need to know about the Redring Powerstream Water Heater

The Redring Powerstream is an electric unvented instantaneous water heater designed to supply up to two outlets.

What does "unvented" mean? - "Unvented" means that the unit is fed from your pressurised water main (as opposed to being fed from an open storage tank using gravity to create the water pressure - vented).

How does that help? - You can have good hot water pressure, even on higher floors. You don't need to purchase special vented taps. You don't need to find room for a header tank in the loft.

What does "instantaneous" mean? - In this case, "instantaneous" means that the water is heated on demand as it passes through the unit via a high power element (as opposed to the water being stored and heated in a tank by a lower power element).

How does that help? - You only use any electricity when you turn on the hot tap ("on-demand"). Also, as the water is delivered immediately, there is no standing heat loss like there is in a hot water storage tank where the water begins to lose heat as soon as the element is switched off.
1. The Redring Powerstream can supply up to two outlets
2. Two Hand Basins
3. One Hand Basin and One Shower
4. One Hand Basin
5. One Shower

I'm stuck for room, can I fit the Powerstream vertically? - Yes, the unit will work either vertically or horizontally mounted and can be fitted below or above the basin.

How energy efficient are they? - You only use any power at all when you open a hot tap because it's the flow of water through the unit which switches it on automatically. As soon as you turn off the hot tap, the unit switches off automatically. This means that they use only very short bursts of energy to give you instant hot water.

Can I use a Redring Powerstream to fill a kitchen sink or even a bath? - Redring technical department will tell you not and we wouldn't advise it as it is not designed for that kind of sustained use and would invalidate your warranty. That being said we have had plenty of examples where clients have told us that they have been doing just that for years without any problems:

Client Example 1 - "My flow rate from my 12KW Redring Powerstream is around 5-6 litres per minute which isn't bad for my shower and it manages to fill a bath in about 20 minutes. Water temperature varies with the time of year as the Powerstream increases it by about 25 degrees C which is fine until winter when I turn down the flow rate from the tap to get hotter water (works a treat). In a cold winter, however, I was waiting around 30 minutes for it to fill the bath."

Client Example 2 - "I put my Redring Powerstream 12KW to the test in that last cold winter and had a go at filling my bath! I took 30 minutes before I had enough hot water to take a bath and I was also able to use my cheap mixer/shower attachment which was powerful enough to have a good hot shower. I know it's not designed for this kind of use but I didn't have much choice and now we're out of winter the bath fills easily in around 10-15 minutes."

Client Example 3 - "My Redring Powerstream supplies the whole house. It would be better if I got another one to reduce the distance of pipework to the bathroom as the temperature drops across 7 metres of pipework. The thing I like most is that I know I'm not using any electricity until I turn on a hot tap. The performance is acceptable for a shower and even a bath after about 15 minutes."

Client Example 4 - "We now have a total of six properties where we have been using Redring Powerstream water heaters to feed the kitchen sinks for years. We have reduced the flow rate into the unit to improve performance and avoid having to use 1/4 turn spray taps. The performance under these conditions have been perfectly acceptable."

If I'm supplying two outlets, can I run them together? - If you are running one tap and then turn it on for a second then the water flow rate will drop on both as the hot water is shared. If the second outlet is a shower, don't use the other tap simultaneously, as the shower flow rate will drop rapidly.

What type of showers can be supplied? - Redring only recommend their shower mixer kit but some clients have had varied success with other manual mixer showers (thermostatic mixers are definitely out).

What kind of water temperature can I expect? - Everything depends on 1. Your water flow rate into the Powerstream. AND 2. The temperature of the cold water entering the Powerstream:

Set your output temperature with the supplied service valve - Open your hot tap fully and then use the service valve supplied to gradually reduce the flow into the unit until the water temperature is at the optimal level. This way you should never have to use your tap to reduce the flow to keep the water hot.

The instructions say that the Powerstream can be set to run at half power during installation. What's that for? - We always assumed that the half-power setting was only for people living in hotter climates who may not need to raise the temperature from their mains water supply by as many degrees due to the water coming in at a higher temperature in the first place. We then had an enquiry from a Dog-Grooming business owner who wanted to use a 9.5KW Redring Powerstream to wash his dogs in conjunction with a mixer shower. The cable he already had installed could only handle around 5KW of power maximum and the installation of a larger cable wasn't an option. As the dogs don't require the water to be as piping hot as we humans like it, he bought one and set it to half power and solved the problem. There is a label inside the unit showing "Hi" and "Lo" Power next to a small screw inside a slider window. Simply loosen the screw slightly and slide it to the "Lo" setting on installation. In this setting, the Powerstream simply uses only one of its two elements to heat the water.

What minimum and maximum water pressures are required for the Redring Powerstream to operate?

How do I find out what my water pressure is? - Your plumber should have a water pressure gauge that he can attach to your system to check your pressure. A suitable water pressure gauge can be bought online for £30-£40.

What if my water pressure is too low because its gravity fed from a tank for instance? - You can boost the water pressure to the required levels with a pump.

What's likely to happen if my water pressure is below these levels? - You'll likely just get cold water or at best a tiny flow rate. You'll need to boost the pressure to the inlet with a pump.

And if my water pressure is too high? - Cold water again. Try opening your hot tap to full and reducing the flow rate to your unit with the service valve provided until the water temperature is at the optimal level.

What size and type of cable will I need to wire it up? - Household twin and earth cable (6242Y) is required to provide an electrical supply to your unit. In a similar way to having an instant electric shower fitted, the Redring Powerstream requires a separate circuit created at your fuse board and a cable running from there to wherever the heater is situated. The size of the cable depends on a number of things:

The KW rating of the Redring Powerstream (9.5KW, 10.8KW, or 12KW)
The length of the cable run from your fuse board to the Redring Powerstream
How the cable has been run (In conduit, clipped direct, etc)
Redring does give guidance on this in their catalogue and PDF instruction leaflet but it's somewhat contradictory. Sizing cables to comply with the regulations is really a job for a qualified electrician, but there are online cable calculators that may help. Here're a couple of examples that I tried:

7 meters "clipped directly to a wall" supplying a 9.5KW Redring Powerstream requires a 6mm cable.
7 meters "enclosed in a thermal wall" supplying a 9.5KW Redring Powerstream requires a 10mm cable.
It is important to have all the information before committing to buying your cable. Summary - The Redring Powerstream Instantaneous water heater is a reliable, versatile, and efficient water heater for getting hot water to outlets in houses and offices where centrally stored hot water is not available or viable. It's the simple design that gives such reliability over many years (Redring currently offers a 2-YEAR WARRANTY to back that up). Outside the warranty period, a full range of spares is readily available to further service the unit if required.

New 'Eco' versions have now been added to Redring Powerstream Range

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Redring's technical department can be contacted on 0344 8793588 for further installation advice