American water heater

[baggy61]

Evening gents,
A customer has bought a rheem 18 Kw tankless water heater and wants me to wire it in. I had a quick look and it has 2x l & n tails in approx 6mm (and E). Spec says to wire through 2 x 40A mcbs but I think this means across 2 phases, not L/N. Emailed advise line to ask about conecting in UK .They said not approved for Canada! D'oh.
Anyone any experience of Rheem or similar ?.
Cheers chaps

 

[telectrix]

from what i have heard, USA get their 220V from using 2 x 110V phases. that's why ( if i am correct). you need to ensure that it's fit for use on UK supply, and if so, MCB in the line only.

 

[baggy61]

Sorry Telectrix, bad description by me, I meant 2 x 6mm live leads and 2x 6mm N leads (& E ).
I think the same as you about bigger loads being across two phases & think N lead might be for controls. The spec sheet says connect through 2x 40Amcb s. I can only see this working if it's got 2 elements with the 2nd kicking in when the flow rate is high.
Thoughts please.

 

[FrankUK]

Have you measured the resistance of the heater elements to see if they are separate?

 

[Marvo]

You need to actually check the voltage that will be engraved on the element tubes. Depending on their required voltage you may be able to rearrange the configuration to run on UK voltages. Be careful, if you make a mistake it will probably cost you an element set.

 

[trev]

Why do people think it's a good idea to buy electrical items overseas which are not made to work in the UK? There seems to have been a bit of a spate of this recently

 

[baggy61]

Hi Frank,
The customer showed me the unit at the side of the road , so no.
You can have a look on rheem.com but don't try on line customer service , they're not the sharpest tools in the box.

 

[baggy61]

It says 240v on spec sheet

 

[FrankUK]

Hi Frank,
The customer showed me the unit at the side of the road , so no.
You can have a look on rheem.com but don't try on line customer service , they're not the sharpest tools in the box.

If you measure the resistance of the elements you can use Ohm's Law to determine the amp draw on 230v UK supply

 

[oldtimer]

First of all are you sure its 18kw so you may have to up your cable size as single phase will be a higher load ie do the math and the reason I ask is an immersion is 3kw and draws about 12 amps also telectrix is right the US has 110v at plugs and light but need 240v supplies for big load items ie cookers so they get that from 2 phases.

I think this is where this forum gets tripped up because in my view its saturated with domestic issues that only deals with single phase 230v yet this is the tip of the electrical industry we work in

 

[chilliwilly]

It will just need a live and neutral supply. If its 18 kw that will be approximately 78amps, so a 80 amp sp mcb will suffice. It may have 2 x 9 kw elements, so you will have to connect them in parrallell as they will be probably be in series/centre tapped if it were designed to have a three wire feed to it, due to the 240v North American residential distribution system.

The only thing that might be of concern is the CE mark, although probably bearing the nema, ul, csa, and the associated standards, it would probably be up to the CE standard.

 

[Engineer54]

Check the inside of the element cover, (Yank gear nearly always have a single line wiring diagram sticker inside) to establish factory connection layout!! 240V is between two phases in the States, so no neutral conductor will be shown.

In the UK, one of the phases will be replaced with a neutral conductor to the elements.

Contrary to popular belief, the supply in the UK is still 240V, the 230V is only a make believe harmonisation voltage, to keep our friends in Europe happy!! lol!!

 

[grantr37]

Evening gents,
A customer has bought a rheem 18 Kw tankless water heater and wants me to wire it in. I had a quick look and it has 2x l & n tails in approx 6mm (and E). Spec says to wire through 2 x 40A mcbs but I think this means across 2 phases, not L/N. Emailed advise line to ask about conecting in UK .They said not approved for Canada! D'oh.
Anyone any experience of Rheem or similar ?.
Cheers chaps

I get annoyed when people buy USA products then ship them here and expect us to get them up and running "wire that in"

 

[Knobhead]

Bear in mind you may need 115-0-115 if there’s any control involved. Depending on how the elements are configured you may have to abandon this project.

 

[Engineer54]

I get annoyed when people buy USA products then ship them here and expect us to get them up and running "wire that in"

You and me both!! ....lol!!