Low Wattage Imerssion heater required

[David1967]

Good afternoon.
I have a holiday caravan that has a low amapage supply. It's a caravan park that has the power supply to a box connected to the caravan from a heavy duty ringmain that supplies 6 vans. The main supply to this van is only a 16amp breaker. I want to get some more water pressure to the shower and sinks, the lpg gas boiler cannot cope with giving me the pressure at the temperature needed.

I have therefore decieded to fit a direct water cylinder with an expansion tank with a 170 Ltr tank with imerssion heater. I am not concerned how long it will take to heat the water as it is not used in large quantities but need to restrict the ampage draw so as not to overload the circuit if I have the kettle, lights or washing machine on. Do they make an imerssion heater rated at 1KW or below and am I thinking on the correct lines that this is the answer?
Thanks in advance for your assitants.

 

[Boilerman2]

No No & NO.. have you considered a Rinnai infinity GAS fired Water Heater??

 

[muggles]

...or alternatively just replacing the boiler with a better one? Does your boiler also provide central heating? If so a combi boiler may be your best option.

 

[David1967]

...or alternatively just replacing the boiler with a better one? Does your boiler also provide central heating? If so a combi boiler may be your best option.

This is a caravan park with only LPG via propane cylinders so no central heating or combi boiler. The current boiler is as old as the van around 8 years old and I would love to get rid of it completely. The gas always runs out at the most inconvienient time plus here you pay for a 16 amp power supply and not the usage. We cook by gas, heat by gas fire hardly use any electricity apart from the washing machine and occaisional cuppa, hence would like to heat the water and get a good pressure to the sinks and especially the shower. The pressure is more important than the recovery time. If I could remove the boiler and put a cylinder heater in ( low wattage)it would give me a small airing cupboard.

 

[1john]

never seen anything less than 3kw cant you use the boiled to indirectly heat the water in the cylinder??

 

[Agile]

Putting a diode in series with a 3 kW element would halve the power taken.

However, this might not cause the items in the display to react as normal.

Tony

 

[muggles]

OK so your heating is covered and you only want to generate hot water. What about an undersink electric water heater? A 15l unit should give you a reasonable shower before it runs out of hot water, if you go for an unvented model it'll provide hot water at mains pressure, and it'll use no gas at all! That way you could dispense with the boiler. Zip Aquapoints draw 2.2kw (9.5A at 230v), but because of the low water content they heat up from cold in about 20 mins, and then come on very infrequently during the day to reheat. You'd probably struggle to run a kettle immediately after having a shower but by the time you've dried off and got dressed it should be about up to temperature and therefore stop drawing power. http://www.waterboilersdirect.com/zip_aqua_point_5_15/

I'm not saying that's the cheapest/best place to get it, it's just the first site that came up on Google, but it gives you some info. It is slightly incorrect in that it says you need a qualified unvented to fit it, which you don't as it's not above 15l capacity. Wiring should still comply though (unless it's different for caravans...)

Alternatively seek out a lower-powered one (I think Ariston Europrisma models are 2.0KW, 8.7A@230v) and see if you can get a very low-powered kettle to go with it, that way you might just squeak under the 16A limit, albeit with a longer reheat time and a longer time waiting for the kettle to boil.

 

[big-all]

ok calculations here 1L off boiled water took 3 mins in a 3kw kettle so thats 1L in 10 mins at 4 amps so 170L will be a whole day plus heat losses

 

[David1967]

OK sorted I think. Thank you guys! I have been reading up on this unvented theory and decieded not to go down that path. A simple economy seven cylinder with 2 immersion heaters. 1 at 1kw for day(managed to find one) and then at night time the 2kw (at the bottom) works through the night.
The head will be low, so will fit a pump for the hot and a cut out sensor so heater will switch off if tank level drops as a safety just incase silly me forgets to switch off the heater before a long lingering shower as I can only get a 20ltr storage tank above the cylinder.
Once again "Thank you" keep up the good work.