3 Phase Power

[davec1001]

Apologies for invading your forum.

My daughter has just purchased a tiny third floor flat in a three floor converted building. We are looking at the feasibility of using an Instanteous heater to save space (ie get rid of current electrically heated cylinder)

It seems our options are limited if we do not have a 3 phase supply to our flat

How big a job is it to provide 3 phase power? I 'assume' that there is a 3 phase supply to the ground floor

Appreciate this is an impossible question......just trying to assess feasibility....so any sort of rough idea would be greatly appreciated

David

 

[ProDave]

What sort of heater power are you looking at? I find it hard to believe it's beyond the capability of a single phase supply.

As for getting a 3 phase feed, you would first have to approach your DNO and get a quote from them. Depending on the infrastructure in place, it might be cheap, or it might be prohibitively expensive.

Then you will need an alectrican to install a small 3 phase distribution board and connect the heater.

Can you give more details of what you are proposing? What the water heater is going to feed etc.

 

[davec1001]

What sort of heater power are you looking at? I find it hard to believe it's beyond the capability of a single phase supply.As for getting a 3 phase feed, you would first have to approach your DNO and get a quote from them. Depending on the infrastructure in place, it might be cheap, or it might be prohibitively expensive.

Then you will need an alectrican to install a small 3 phase distribution board and connect the heater.

Can you give more details of what you are proposing? What the water heater is going to feed etc.

We are at the early stages of planning this.........

The water heater will only supply a Shower, a wash basin and a kitchen sink.....Happy to accept single use of each of these. However I am worried about the flow rate to the shower........it appears that a 12kW unit provides 6 litre per minute.......which is about half of what a 'power shower' would provide.

I am trying to make sure we understand all the implications of the decision

The decision is essentially, inline electric water heater and tidier space optimised installation versus new cylinder, electric immersion and pump.

Thanks for your response

 

[NozSpark]

Why not divert the immersion supply to one of these

Speedflow Premier Undersink Unvented Water Heater 15L

and get an instantaneous electric shower installed?

 

[davec1001]

Erm,

Agreed that is an option.........

But I am still left with the limitation of flow rate of a single phase solution.

That option would seem to be better if I wanted simultaneous use of sinks and shower.....which isnt a priority

Thanks for the idea.

 

[NozSpark]

TBH I think that you'd find the instalation costs of a three phase supply prohibitive.

Those under counter heaters are more than capable of supplying two sinks

 

[davec1001]

Ok thanks You guys have been helpful.

 

[ProDave]

Is space in the flat THAT short that you really have to remove a hot water tank? That will give you about 1 cubic metre or less of extra cupboard space.

Is there not a loft space you could relocate the tank to?

If 12KW of instantaneous water heating will not satisfy your showering needs, then you are, like me, used to a GOOD shower. Even getting a 10KW electric shower would probably disappoint you.

The sink, basin etc can easily be catered for by a smaller under unit heater like the one suggested above. My initial question was really are you wanting enough water to fill a bath? If so, then ANY instantaneous heater would give you such a pathetic flow rate that it would take forever to fill a bath. But I guess if the flat is as small as you say, there's no room for a bath is there?

So you choice really comes down to accepting the lower flow rate of a 10KW electric shower (compared to a power shower), finding a new home for the hot water tank, or just making do with the limited space.

I suspect even if you could get a 3 phase supply, and find a really high powered instantaneous water heater, it wouldn't be a great deal smaller than the hot water tank, so you wouldn't save that much space. Most 12KW single phase heaters are a similar size to a wall hung boiler for instance.

 

[davec1001]

Ok...ProDave's post caught exactly the question

It's about trade offs.

I just had a quote from the DNO. 1800 to 5k to install a 3 phase supply if it doesnt exist.. So I think this cost and your comments leaves me to either accept a 6L per minute shower or keeping a hot water tank and pumping it.

Thanks very much, Very Helpful discussion

 

[shed69]

I was always under the impression that the dno won't give 3 phase to a domestic?????

---------- Post Auto-Merged at 14:32 ---------- Previous post was made at 14:31 ----------

I know they will to communal mains cupboard but not the dwelling...

 

[Manator]

I was always under the impression that the dno won't give 3 phase to a domestic?????---------- Post Auto-Merged at 14:32 ---------- Previous post was made at 14:31 ----------

I know they will to communal mains cupboard but not the dwelling...

They will supply 3 phase if it is warranted.

I do not think a 3 phase supply would be required for your problem. An electric shower fed from the mains cold water will get over the problem of the shower, and many of the under sink type of water heaters are very capable these days of doing 1 or 2 sinks.

 

[Evans Electric]

I'd forget the 3phase option Davec1001 .

What do you see as a "Power Shower" , a riot police water cannon type that delivers 100 ltrs /sec and flattens you against the cubicle wall or a normal electric shower ,which would cover your needs I would imagine ,( 8.5 or 9KW is all you need, coupled ,as the others have said , with an undersink water heater .

I assume there is no bath in the flat.

 

[ProDave]

I'd forget the 3phase option Davec1001 . What do you see as a "Power Shower" , a riot police water cannon type that delivers 100 ltrs /sec and flattens you against the cubicle wall or a normal electric shower ,which would cover your needs I would imagine ,( 8.5 or 9KW is all you need, coupled ,as the others have said , with an undersink water heater .

I assume there is no bath in the flat.

You clearly have never used a REAL shower Deke?

Our main shower, is a thermostatic mixer shower fed from a mains pressure unvented hot water storage tank, and with a mains pressure of over 3 Bar, gives a flow rate good enough to knock you into next week.

By comparison, our other 8.5KW electric shower is a pathetic dribble. Even going up to a 10KW shower would not get anywhere near the flow rate of a real shower.

I think the OP has a vented hot water tank, with a mixer shower and a pump, so that probably gives a similar decent flow rate to his present shower as we get from our unvented system. I think he was looking for a really high power instantaneous water heater to try and replicate that flow rate, rather than "put up with" the lower flow rate of even a 10KW electric shower.

 

[a3]

Mr Smith told me that Deke doesnt Shower.......

 

[shed69]

Stinking Scots.... need a good shower that knocks them into next week!! Or at least into England - Land of the great...!!

 

[SLIPSHOD & SLAPDASH]

In addition to the supply company costs you have building costs on your own property. You would have to provide ducts, & risers for them at your cost. In addition to this you would have to obtain permission from the freeholder to alter the property. The DNO may only want to terminate a new supply externally & for yourself to get the cabling up to the 3rd floor. I doubt the freeholders would allow any of this.

 

[kme]

There IS another option, I think.

You could replace the existing tank with an unvented type - so you would get rid of the header.

Avoids the necessity for a pump on the shower - mains pressure hot water, same as you`d get from an instantaneous water heater - but without the huge cost factor.

Can be heated from a standard immersion, or the CH system - or both.

??????