'Water Powered' Immersion Heater

[Andy]

Hi

Many years ago my father purchased a heat exchanger that screwed into the immersion heater flange in a hot water cylinder. The device had 15mm connectors and was connected to the boiler circulator system (which was pumped) to increase the heat transfer into the tank. I seem to recall that it would dissipate something like 40kBtu. Can anyone tell me if such devices are still available and, if possible, give me names of suppliers or manufactures to search with?

Regards - Andy

[Derek *]

I remember one such device that went into the immersion heater boss. ISTR it being called or made by "Salamander".

Unfortunately (same company or not) there is a company called Salamander Engineering which seems only to make water treatment products, but which turns up unfailingly in Google searches.

:-(

DG

[Dave Plowman (News)]

ISTR a UK one called a 'Sidewinder'?

[burbeck]

hi andy, they are called 'sidewinders' made by yorkshire heating regards bob

[Andy]

Hi

Thank you all very much for your responses. I've had a good 'google' with the information you provided but drawn a blank up to now. Seems like that they're probably not made any more.

Thanks again - Andy

[Dave Jones]

9

[Andy]

Thank you very much Dave. Just what I wanted.

I called in the local Travis Perkins this morning and they spoke to Salamander who said that they've just stopped making their version of the same thing that was called 'Hot Tube'. Salamander still have some in stock so their sending me a list of what sizes are available.

Regards and thanks to all again - Andy

[Doctor Evil]

One is called a sidewinder, but it does not fit into the immersion bosse being an involved job to insert a standard coil into a cylinder cutting holes in the cylinder. The one that does is the Micraversion, both made by Yorkshire. There was a few other companies doing them, but demand for them is small. They were made when indirect cylinders were expensive, which is not the case today. I usually find it is cheaper to replace the whole cylinder than mess with these. They are not that efficient. Best get a quick recovery coil cylinder. Well worth it, as you could drop your fuel bills and produce more hot water as they take all the boilers output.

With the 15mm connection Micraversion, make sure enough flow is through the boiler.

I recall one being used with the cold water mains through to create an instant high pressure shower. It didn't work too well as the coil is not big enough. To get it to work near properly the temperature of the cylinder had to be raised to 78C and a blending valve fitted on the DHW outlet to lower tap water temp. May as well buy a purpose made shower coil cylinder with a quick recovery coil and get proper performance all around.

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[Aidan]

Hotspring conversion coil, converts direct cylinder to indirect. 22mm =A3 61.83 list

Yorkshire Micraversion converts direct cylinder to indirect.400mm =A383.74 list, 670mm =A389.23 list

I think these require drilling of the cylinder wall, rather than screw into the immersion heater boss. All above ex-vat, available from City Plumbing Supplies. However, IMHO a waste of time, you'd do better to buy a whole new cylinder.

[Andy]

Hi

Thanks again to all the posters for the excellent info and advice.

Yep, having done a bit more research when I've had chance today I'm coming to the conclusion that a new tank is the answer. The tank I have is only a few years old with an indirect coil and no immersion heater fitted. I was hoping that I could use one of these devices to augment the existing heat exchanger and boost the heat transfer in preparation for fitting a power or venturi shower unit. I will likely have to remove the tank to fit the heater and a Surrey flange anyway so a new tank is probably the best option.

Is there anything in particular I need to look for when looking for a 'quick recovery' tank? I'm not looking for anything special, just something adequate for a medium 3 bedroom semi with one bathroom and a 50kBtu/h conventional gas boiler.

Regards - Andy

[Andy]

Is there any chance you could give me an idea of the name of products I should looking at?

Andy

[John Armstrong]

One complication here is that replacing the hot water cylinder now comes under building control, whereas modifying the existing probably doesn't.

[Doctor Evil]

indirect version. Use a normal high pressure thermostatic shower mixer. If the shower does not perform as well as you thought. Ramp up the cylinder temperature and install a DHW blending valve on the draw-off. Comes with a pressure reducing valve. Take the cold off this vale too. Will give a high pressure shower without any pumps and minimal disruption.

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[Andy]

Andy

[Doctor Evil]

Andy

Best to say what you want to achieve, and any constraints, then a solution(s) can be suggested.

Also get a cylinder, that is any cylinder you buy, with a thermostat probe. This takes a rod type of cylinder stat, which senses the water temp from inside the cylinder. Also get a quick recovery primary heating coil too. A boiler of around 25kW will dump all its heat in the cylinder and be re-heating as you draw-off hot water, extending the cylinder size in essence.

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[Andy]

Here you go then:-)

Project: Complete refit of bathroom in small-medium 3 bedroom semi with single bathroom/toilet on first floor. Room is 1.9m square and will be completely stripped and will have new suite, tiling etc. Upstairs walls are all of 4" solid block construction. No room for separate shower so it will have to go over the bath. Facilities normally used by 2 adults plus another 2 when the offspring are home from Uni. (Which, in reality, is over 1/3 of the year!)

Current installation; Glow-worm Ultimate 50BF conventional boiler (50kBtu/15kW) on ground floor pumped via 3 way valve to heating and hot water cylinder. Boiler is only a couple of years old. Indirect hot water cylinder in airing cupboard leading off bathroom. Cylinder is 900x450mm120 litre basic item which is fed from 20 or 25 gallon cold water tank which is located in the attic immediately above the airing cupboard. There is about 0.5m head from the water level in the header tank to shower head height in the bathroom. The rising main supply is good, 5 bar static and 3.5 bar at 20l/m. All cold water taps in the house are fed from the water main. Current shower is a circa 8 kW electric which is unreliable and inefficient. Apart from the shower, everything currently works fine; system heats house well and provides plenty of water for baths etc.

One objective is to replace the electric shower with something better and more efficient. I'm not looking for a Rolls Royce system, just something that is a good bit better than the electric shower. If possible, I also like to end up with a system which is reliable and doesn't need attention or replacement parts from time to time. I'd prefer the system to be quiet as possible when running.

Constraints. SWMBO wants to keep an airing cupboard. I don't want to change the boiler. Due to the attic construction and location of load bearing walls, it would be difficult (but not impossible) to raise or fit a larger cold water header tank without having to move it a considerable distance horizontally from the hot water cylinder. There is nowhere to extend the bathroom. I don't want to have to alter the boiler system or the circulator pipes below where they come through the floor in the airing cupboard.

Options so far:

1. Venturi shower. My preferred option but having googled in this group there seems to be a fair bit of disagreement about their efficiency. Also there doesn't seem to be a wide range of available products. Trevi Boost, New Stream Jetstream & Hydroflo VS2 are all I can find in the Net. I'm told that H2O make one also but there is nothing on their site.

1. Low pressure mixer without pump. I would probably need to raise the height and increase the size of the cold header tank which would not be easy.

2. High pressure mixer with dual pump. Pump noisy & unreliable? Might have to increase size of cold header tank

1. High pressure mixer fed from water main direct and via shower coil. Would have to change hot water cylinder but this might be cheaper than the 2 or more pumps I might have to buy over time. (I'm currently awaiting feedback from Telford and RCM on availability, cost, etc.of such tanks.) I was already thinking I might need to move to a 'rapid recovery' tank anyway, particularly if I was going for one of the pump options.

2. High/low (?) pressure mixer (thermostatic) with cold from the mains and hot via a pump such as: . I cannot find any information about this other than the advert on DPS's Heatweb site. This looks very much like a central heating pump to me so I would imagine it would be reasonably quiet and reliable.

1. Give up and fit a 10kW electric shower with the necessary upgraded cable and RCD isolator. Very unlikely!

I'm still leaning toward the Venturi option but need to satisfy myself that they work. I have just spoken to Ideal Standard about the Trevi who say they need

1.5 - 3 bar cold and down to -0.5m head for the hot. The shower supplies 12 l/m with 1.5 bar cold and a hot water temperature of 65 deg. I might need to regulate the cold pressure.

Any help or advice will be appreciated - Andy

[Doctor Evil]

I would go for the shower coil cylinder with a quick recovery coil, killing many birds with one stone:

- mains pressure shower

- quick recovery means cheaper gas bills

- quick recovery means the cylinder is effectively larger as it will produce more hot water.

- quiet (no noisy pumps).

- shower coil is simple

- shower coil is reliable,

- greater control at the mixer

- cheap to run with water heated by gas.

- a cheaper shower mixer valve can be used too.

- the existing system has no disruption except a cylinder change.

- no electrical work.

The only tap you need high pressure at is the shower. The cold water feeding the cold tank in the loft usually runs up inside the airing cupboard meaning all the pipework is in the cupboard.

I would avoid pumps. Second option would be a venturi shower.

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[Andy]

Yep, that's just about where I'm at now. If only I could get some info back from the likes of RMC and Telford I'd be able to get things moving. I'll try ringing a few manufactures or suppliers in the morning - they obviously don't like e-mail.

Thanks very much indeed for your help.

Regards - Andy

[Doctor Evil]

Telephone is the only way. The suppliers can at times give better deals than the recommended prices.

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