Thread: Electricity

Originally Posted by crippen

Thermo-couple !

Well, yes that is the heat sensor.
It's output is fed into a regulator, the Triac.

I have one of these water heaters. I wonder how it copes with spikes of lightning on the mains?

Is this what you got ?

DH-10BM1T

Originally Posted by crippen

Thermo-couple

or a PT100 RTD ?

No understand. Google it Yes one of them!

At 10KW you theoretically draw 50% less current from the grid than at 5KW. At 5KW you theoretically need to mix less cold with the hot for a shower of the same time duration. Simple really, just turn the bloody thing down to minimum and inject less cold water through your mixer. The more current you draw from the grid, the larger your power bill. Current is the stuff that makes your power meter spin around and builds up numbers on that dial in your meter box. The power company reads the dial and calculates the bill from the amount of current that you have drawn since the last bill. You might see this expressed on your bill as KWh or Kilowatt hours. The less of these fellas the better for a small bill.

If you want to get a better understanding of what your appliances are using, The power equation P=IxV might help.

Now, P means power (measured in Watts)
I means current (measured in Amps)
V means voltage (measured in Volts)

So if theoretically you had a device which was said to produce 10KW or 10,000 Watts of power where the voltage was 220, you would have a power equation which would look like this: 10,000 = 45.45x220. You theoretically would be drawing a lot of current(45.45 Amps) and it would be very expensive.

Another example would be that of a 220V personal body massager. It may only produce power of .5 Watts. In this case the equation would be very different.
P=IxV = .5W=.003Ax220V. So you can see the personal body massager draws much less current than your hot water heater and consequently costs you heaps less.

Originally Posted by Johnny Longprong

At 10KW you theoretically draw 50% less current from the grid than at 5KW. At 5KW you theoretically need to mix less cold with the hot for a shower of the same time duration.

Make it the other way around and it will be correct.

Originally Posted by lom

Originally Posted by Johnny Longprong

At 10KW you theoretically draw 50% less current from the grid than at 5KW. At 5KW you theoretically need to mix less cold with the hot for a shower of the same time duration.

Make it the other way around and it will be correct.

Whoops. Too many vinos again. Hic!!

Jesus I'm glad JLP aint gunna be wiring up my shack ... sorry mate ya fired

Originally Posted by lom

Originally Posted by woodenshoe

in my book a 10.5 KW electric device would require 1 ph 220v 25 amp or 3ph 380v 16 amps.

10500/220 = 47.5 amps. One needs a 10 sqmm cable for that..

No such thing as a 10kw heater. Correct Power equals I X V. 10kw is like 5 two bar fires and unless you've have special cable fitted, like paralleled cooker cable then all that would happen is you would start a fire.

IET Forums - 10kW water heater on a 30A breaker

Originally Posted by the dogcatcher

No such thing as a 10kw heater.

I have quoted two.
Are you blind or stupid ?

Originally Posted by Johnny Longprong

Originally Posted by lom

Originally Posted by Johnny Longprong

At 10KW you theoretically draw 50% less current from the grid than at 5KW. At 5KW you theoretically need to mix less cold with the hot for a shower of the same time duration.

Make it the other way around and it will be correct.

Whoops. Too many vinos again. Hic!!

Power equals voltage times current. At 10kw you draw twice the current than 5kw. If you double the volts then you can halve the current but that's not possible. Inlet and outlet flow have no bearing. less water in will equate to less water out and visa versa as the water system is essentially a series system. Let less in or out will just mean hotter water. there will be no difference in electricity used.

Quoted at 10kw same way as music systems quoted at 200 watts. 10kw systems sound good so you buy them, 6.6kw max on 30 A breaker. Maybe you need to understand the quoted wattage. R.M.S. or peak.

Originally Posted by crippen

IET Forums - 10kW water heater on a 30A breaker

Just read it. I refer you to the post that talks about inductive loads, although no one mentions that true power is always RMS in AC systems

good, Miggins is very confused...as normal

the best way to check what is happening is to remove the cover whilst in the shower and have a poke about

Originally Posted by the dogcatcher

Originally Posted by lom

Originally Posted by woodenshoe

in my book a 10.5 KW electric device would require 1 ph 220v 25 amp or 3ph 380v 16 amps.

10500/220 = 47.5 amps. One needs a 10 sqmm cable for that..

No such thing as a 10kw heater. Correct Power equals I X V. 10kw is like 5 two bar fires and unless you've have special cable fitted, like paralleled cooker cable then all that would happen is you would start a fire.

No such thing as Santa Claus too !

Originally Posted by the dogcatcher

Quoted at 10kw same way as music systems quoted at 200 watts. 10kw systems sound good so you buy them, 6.6kw max on 30 A breaker. Maybe you need to understand the quoted wattage. R.M.S. or peak.

Not on a 30 Ampere breaker, we are on a 60 Ampere set up, (that used to deliver about 5 amps - nor is it 220V it is 233Volt)

And AC is a little different to DC - Phase, RMS "Z" rather than "I"etc, etc. they are not really the same.

Originally Posted by Missismiggins

Plus the arseholes we had sorting out the house didn't help by painting it completely white with emulsion....it says on the side "Don't clean with thinners" how was I to know that the fuckwits we employed would paint a water heater...nothing ceases to amaze me....we had a bunch of fuckwits tile the bathroom, and I made a joke - see what they do with the border tiles (just a joke nothing more) I came back 6 hours later to find the fucking idiots had tiled all the border tiles in a 1 metre square...I took photos ...they didn't come out! A fucking five year old would have had more comprehension - then half of the fuckwits went home and wouldn't come back because the supports for my home are old trees and "possesed by ghosts" for fucks sake!

maybe they went home because you were the arsehole?

Yeah, ok. 6.6 kw dc. is about 4.5 ac kw. 1.414, 0.707. RMS

Originally Posted by Missismiggins

Originally Posted by the dogcatcher

Originally Posted by lom

Originally Posted by woodenshoe

in my book a 10.5 KW electric device would require 1 ph 220v 25 amp or 3ph 380v 16 amps.

10500/220 = 47.5 amps. One needs a 10 sqmm cable for that..

No such thing as a 10kw heater. Correct Power equals I X V. 10kw is like 5 two bar fires and unless you've have special cable fitted, like paralleled cooker cable then all that would happen is you would start a fire.

No such thing as Santa Claus too !

3 phase. 415 volts across phase. Consumer supply. I don't think so.

I think the mixer valve you refer to is actually a flow control . Increase the flow the water cools reduce the flow and the water gets hotter. You still use 10kw Hope this helps

does it heat water for domestic use sink ect

Miggs,
After reading all the interesting replies to your question I hesitate to add anything but will attempt anyway. Apparently the watt settings on your water heater also limit the water temp. It appears to be an electronic control with no external thermostat for you to adjust. Two answers and both have already been submitted, first, flow and temp have nothing in common until you exceed the flow rate while showering. 2nd, 6kw is what the device uses whenever it is heating water. That heating rate would heat water faster than a lower setting. You can test the "re-heat rate" by lowering the wattage setting to either of the lower settings, say for 24 hours, then showering. Any noticeable difference in the shower? Should take less "mixing" at a lower wattage as the water temp should be lower accordingly.
Your first question was askew as flow and wattage settings are not comparable.
I hope this hasn't confused the issue further. If you don't like how hot the water is at 6 kw then try lowering it one step at a time. Since anti-scalding valves seem to not have made it to Thailand yet, that might be a safer method for children who possibly could scald themselves with really hot water.

Jim