Hi everyone. Is there a low wattage electric shower suitable for use in the van? With mains water available at a lot of pitches these days, would mean an end to very short showers due to very small hot water tank! Thanks
Electric shower in van???
- Thread starter ClairePP
- Start date
Claire PP said:
And all pitches tripping because some one has switched on their electric shower. We find the hot water in the tank more than enough for a shower, however we use common sense when showering.
- Mar 14, 2005
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Hi there,
Electric heating is
always 100% efficient, so there is no magic formula that will allow a
low wattage heater perform like a more powerful one.
Electric showers in
caravans are not really practical. You are severely limited by the
maximum power available via the hook up to instantaneously heat the
water. Caravans only have a maximum 16A supply to a caravan the
biggest heater could only be 3.6kW and of course many sites limit you
to 10 or even less amps with a corresponding reduction in the heater
size.
The smallest electric
showers in domestic properties are 7.5kW which most people would find
only just usable in fact most domestic showers are now rated nearer
10kW or more.
Simply not enough
heating capacity to provide an adequate flow of hot water.
Electric heating is
always 100% efficient, so there is no magic formula that will allow a
low wattage heater perform like a more powerful one.
Electric showers in
caravans are not really practical. You are severely limited by the
maximum power available via the hook up to instantaneously heat the
water. Caravans only have a maximum 16A supply to a caravan the
biggest heater could only be 3.6kW and of course many sites limit you
to 10 or even less amps with a corresponding reduction in the heater
size.
The smallest electric
showers in domestic properties are 7.5kW which most people would find
only just usable in fact most domestic showers are now rated nearer
10kW or more.
Simply not enough
heating capacity to provide an adequate flow of hot water.
Parksy
Moderator
- Nov 12, 2009
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As Prof John said, electric showers are not really practicable for caravans but you could try to maximise the use of the hot water that is available.Claire PP said:
I take your point about the available mains water but the capacity of the boiler is a limiting factor.
We tend to use the water to get ourselves wet first, turn off to use shampoo and shower gel and then turn on the water to rinse, using this method conserves the hot water that's available to you.
With this in mind some caravanners replace their caravan shower head with a trigger operated model, Click Here to see an example.
- Jun 20, 2005
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Hi Claire
See this link
http://www.caravantalk.co.uk/community/topic/43291-electric-showers/
We both find we can shower adequately in the caravan using Parksy's method.
I find using the cold water from the onboard tank gives a higher pressure than straight from the aquaroll.
Realistcally what you seek is just not practical.
See this link
http://www.caravantalk.co.uk/community/topic/43291-electric-showers/
We both find we can shower adequately in the caravan using Parksy's method.
I find using the cold water from the onboard tank gives a higher pressure than straight from the aquaroll.
Realistcally what you seek is just not practical.
an electric shower is not practical in a caravan your shower at home needs to be wired directly to your consumer unit using 10mm cable to a 45 amp circuit breaker in order for you to get a big enough element to heat the water at a reasonable flow rate site bollards are normally 16 amp and your hook up lead is 2.5 mm cable all you could realisticaly run is a hand wash unit which is rated at 3000 watts which is 13 amps at 240 volts the flow rate to heat that would be so slow it would only be a trickle hope this answers your question without baffling you to much cheers craig
Have thought about fitting an additional electric water heater such as a Whale
http://www.whalepumps.com/rv/product.aspx?Category_ID=10000&Product_ID=20&FriendlyID=Water-Heater-8ltr
and having this preheated.It wouldnt give loads more but every little helps
http://www.whalepumps.com/rv/product.aspx?Category_ID=10000&Product_ID=20&FriendlyID=Water-Heater-8ltr
and having this preheated.It wouldnt give loads more but every little helps
Damian
Moderator
- Mar 14, 2005
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Most caravans are already running at the maximum electrical load as dictated by the specification.
Adding any other electric high load unit will severely test your housekeeping as you will have to remember to turn various items off to use others, or trip the site bollard.
Remember also that your excesive drain may be enough to trip the main circuit breaker and deny everyone else of power whilst the now very unhappy owner has to reset the trips.
If you want faster heat up for showers, use the gas and electric heating, already built in to your heater, together.
Another item from the Original Posting, which has not been covered so far, is that whilst mains water is available on many pitches, you CANNOT put mains pressure water anywhere near your van pipework.
It MUST be reduced in pressure which means many electric heaters will not have enough pressure to work, even if you did hard wire it to a 45amp breaker etc.
Adding any other electric high load unit will severely test your housekeeping as you will have to remember to turn various items off to use others, or trip the site bollard.
Remember also that your excesive drain may be enough to trip the main circuit breaker and deny everyone else of power whilst the now very unhappy owner has to reset the trips.
If you want faster heat up for showers, use the gas and electric heating, already built in to your heater, together.
Another item from the Original Posting, which has not been covered so far, is that whilst mains water is available on many pitches, you CANNOT put mains pressure water anywhere near your van pipework.
It MUST be reduced in pressure which means many electric heaters will not have enough pressure to work, even if you did hard wire it to a 45amp breaker etc.
Hi Everyone. Thanks for all your comments.Must say we have never had a problem with showering in the van.It was just a thought when hubby stayed in too long trying to defrost after fishing last weekend!
Claire PP said:Hi Everyone. Thanks for all your comments.Must say we have never had a problem with showering in the van.It was just a thought when hubby stayed in too long trying to defrost after fishing last weekend!
You could always fit another boiler to work in series wirth the existing boiler.
The previous generation in the 1960's could put a man on the moon but it's doubtful whether the West could do it now, we also designed and built supersonic passenger jets, can't even do it for a car nowadays.
Seriously though, if I was going to build a "proper" shower for a caravan that didn't run out of water I would do it with gas, there would be no trouble supplying enough energy to heat the water on demand. Whether people would be happy burning gas when they are connected and paying a flat rate for electricity is another matter.
Seriously though, if I was going to build a "proper" shower for a caravan that didn't run out of water I would do it with gas, there would be no trouble supplying enough energy to heat the water on demand. Whether people would be happy burning gas when they are connected and paying a flat rate for electricity is another matter.
After a day on the water we often need to "defrost" as well. Running the water heater on gas provides faster heating. We turn to gas as soon as we get back to the van. My wife found a water saving very fine spray small shower head on Amazon. When cold we close the blown air heater vents in the van and only have the bathroom vent open when showering.Claire PP said:Hi Everyone. Thanks for all your comments.Must say we have never had a problem with showering in the van.It was just a thought when hubby stayed in too long trying to defrost after fishing last weekend!
The kettle is normally on the hob as we shower and that helps keep the rest of the van warm. The fine spray gives both of us enough combining the water with the heat from the blown air we can both defrost.
I believe that some heaters can also have the gas temperature increased by altering and internal thermostat May be an expert can advise if that would help.
Our sports can leave us pretty cold, paying for a bit of gas is well worth it for the comfort.
I wish I could help with an electric shower idea for you, but I can't quite, jsut yet.
I dislike the whole "5 minute caravan shower" especially after you may have paid thousands of pounds for a caravan for it to be fitted with a small capacity water heater that takes an age to heat up:
Truma's Electric boiler: 14 litres of water, 70mins to heat 15-70degrees, that is pretty poor by my standards, but then again it is only 850watts.
I had an idea ages ago of using a 3kw instant water heater plumbed up to a tank, so that you'd switch it on, pump through and ehat up X amount if litres of water into your hot water tank, then when you want to use it, pump it out with a standard pump set up.
Tom.
I dislike the whole "5 minute caravan shower" especially after you may have paid thousands of pounds for a caravan for it to be fitted with a small capacity water heater that takes an age to heat up:
Truma's Electric boiler: 14 litres of water, 70mins to heat 15-70degrees, that is pretty poor by my standards, but then again it is only 850watts.
I had an idea ages ago of using a 3kw instant water heater plumbed up to a tank, so that you'd switch it on, pump through and ehat up X amount if litres of water into your hot water tank, then when you want to use it, pump it out with a standard pump set up.
Tom.
- Mar 14, 2005
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To answer Mels plea - Caravans hava a maximum of 16A of electrical supply, and in many places even less than that. with 16A supply you only get 3.6kW of heat energy, and pro rata with lower site current limits. Some continental sites are as low as 3A which is only 690W. Its a scientific and engineering impossibility to make a given current rating to produce more heat.
There are 3kW (13Amp) hand wash heaters. A system that used one of the heaters with a shower hose could be engineered, but it can only be used when the sites supply allows 13A or more to be taken. you could not use it when the sites supply is less than 13A.
Assuming the electrical supply is available, the water flow at your desired temperature in litres an minute will be very small, and most people would find inadequate for showering.
Variations in water supply pressure due to other caravanners taking water from the mains could possibly lead to scalding.
Mains instantaneous electric showers simply will not be a satisfactory solution in touring caravans.
Static caravans have used gas powered instantaneous water heaters for many years. Originally they were the old Geyser type, but now-a-days they have to be a room sealed device which could in theory be fitted to touring caravans. To get enough heat into the water at high flow rates the heaters tend to be less efficient, so to get 9kW heat into the water you may burn 12kW or more. This is quite a large amount gas which may compromise the gas systems in touring caravans.
The lpg regulators fitted to caravans will have a maximum gas throughput, which if you exceed the limit the regulator will not be able to control the gas pressure properly. And each gas bottle has a limit as to how much gas you can take off, and that depends on the ambient air temperature. Try to take too much gas and the bottle will reduce how much gas it can liberate. almost a self limiting feature.
But of great importance is that these heaters do not like variable water pressures. Sudden changes in water pressure and flow can cause the water in parts of the heater to boil and turn to steam which is definite no no. This is one of the prime reasons why Instantaneous water heaters have not been fitted in touring caravans in recent years.
For reasons of control and safety, the best solution is a storage heater with a small wattage element. Perhaps larger well insulated tanks would be a solution to give more hot water. Electrically heated tanks could be engineered in various shapes to utilise otherwise wasted space. Perhaps a tall tank fitted in the wardrobe, or behind the corner vanity unit in the shower room - a variation on Toms suggestion.
There are 3kW (13Amp) hand wash heaters. A system that used one of the heaters with a shower hose could be engineered, but it can only be used when the sites supply allows 13A or more to be taken. you could not use it when the sites supply is less than 13A.
Assuming the electrical supply is available, the water flow at your desired temperature in litres an minute will be very small, and most people would find inadequate for showering.
Variations in water supply pressure due to other caravanners taking water from the mains could possibly lead to scalding.
Mains instantaneous electric showers simply will not be a satisfactory solution in touring caravans.
Static caravans have used gas powered instantaneous water heaters for many years. Originally they were the old Geyser type, but now-a-days they have to be a room sealed device which could in theory be fitted to touring caravans. To get enough heat into the water at high flow rates the heaters tend to be less efficient, so to get 9kW heat into the water you may burn 12kW or more. This is quite a large amount gas which may compromise the gas systems in touring caravans.
The lpg regulators fitted to caravans will have a maximum gas throughput, which if you exceed the limit the regulator will not be able to control the gas pressure properly. And each gas bottle has a limit as to how much gas you can take off, and that depends on the ambient air temperature. Try to take too much gas and the bottle will reduce how much gas it can liberate. almost a self limiting feature.
But of great importance is that these heaters do not like variable water pressures. Sudden changes in water pressure and flow can cause the water in parts of the heater to boil and turn to steam which is definite no no. This is one of the prime reasons why Instantaneous water heaters have not been fitted in touring caravans in recent years.
For reasons of control and safety, the best solution is a storage heater with a small wattage element. Perhaps larger well insulated tanks would be a solution to give more hot water. Electrically heated tanks could be engineered in various shapes to utilise otherwise wasted space. Perhaps a tall tank fitted in the wardrobe, or behind the corner vanity unit in the shower room - a variation on Toms suggestion.
Mel
Moderator
- Mar 17, 2007
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There you go Prof, you started off saying it couldn't be done and a few paragraphs later you've practically invented a showering soluion. Get yourself on Dragons Den and get it in production. Just remember those of us who inspired you when you are a multi millionnaire.
mel
mel
- Mar 14, 2005
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Hello Mel,"There you go Prof, you started off saying it couldn't be done and a few paragraphs later you've practically invented a showering soluion."
Not quite true, what I said was that an electric instantaneous water heater is impractical. Gas ones are possible but storage is the most practical solution. But that been done - First Carver in 1979 (Cascade 1) , then Truma (Trumastore), Fiama and others have followed. As far as I know only Truma do a large capacity (14L) version, But Ive been out of the industry for 13 years so what do I know?.
But I do claim copyright on anynew tall heaters or moulded heaters, so start the begging letters now.
Not quite true, what I said was that an electric instantaneous water heater is impractical. Gas ones are possible but storage is the most practical solution. But that been done - First Carver in 1979 (Cascade 1) , then Truma (Trumastore), Fiama and others have followed. As far as I know only Truma do a large capacity (14L) version, But Ive been out of the industry for 13 years so what do I know?.
But I do claim copyright on anynew tall heaters or moulded heaters, so start the begging letters now.
Whale water heater 13lt of water and with both gas and electric together, heats one litre of water from 15C to 75C, a 60C rise, in a tad under two minutes.
Temperture apart, the main restriction to caravan gas supply is the diamerter of the gas bottle containing it. The liquid can only evaporate into gas at the surface, so it is the area of the surface of the gas, restricted by the size of the bottle, than is the real problem. Solution to this is cart a single 47kg around! or link multiple small bottles together
Temperture apart, the main restriction to caravan gas supply is the diamerter of the gas bottle containing it. The liquid can only evaporate into gas at the surface, so it is the area of the surface of the gas, restricted by the size of the bottle, than is the real problem. Solution to this is cart a single 47kg around! or link multiple small bottles together
- Mar 14, 2005
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Hello gary,
The whale is a realtively new product and falls within my 13year window, so I do not have detailed knowledge of them.
I'm not sure where you get your information about heat up times, but in the context of instantaneous showering even the 1 litre in 2 min is insufficient. In fact the tank holds 13L, looking at the Whale specification:-
http://www.whalepumps.com/rv/siteFiles/resources/docs/resource-library/WaterHeaterWH1302technicalspecifications.pdf
it states approximate 22 minutes for a 15 to 70oC rise using both gas and mains combined. There is no mention of quick heatup times for smaller quantities.
The 8L version has a quicker heat up time of only 12min, but that is still way off the mark for instantaneuous showering.
Most of the previously mentioned makes and models in the thread will also provide a small quantity of hot water after a few minutes, simply due to the stratification caused by convection of hotter water rising to the top of the tank, so its not really new or ground breaking performance. After few minutes of heating the initial burst of hot water will not be maintained at that temperature, as they all use displacment of hot water by cold to deliver the flow. The introduction of the cold water rapidly disturbes the stratifiacation and mixes the hot with cooler water lowering the output temperature. The longer the heater is on the more bulk of hot water is available so the cold dilution rate is slower.
You are then limited by the heat input rates, which for the reason already given cannot provide enough instantaneous hot water.
I find that turning on the water heater as soon as you get on site allows enough hot water to be generated to wash hands etc after you have done the essential steadies, and collecting water etc.
The whale is a realtively new product and falls within my 13year window, so I do not have detailed knowledge of them.
I'm not sure where you get your information about heat up times, but in the context of instantaneous showering even the 1 litre in 2 min is insufficient. In fact the tank holds 13L, looking at the Whale specification:-
http://www.whalepumps.com/rv/siteFiles/resources/docs/resource-library/WaterHeaterWH1302technicalspecifications.pdf
it states approximate 22 minutes for a 15 to 70oC rise using both gas and mains combined. There is no mention of quick heatup times for smaller quantities.
The 8L version has a quicker heat up time of only 12min, but that is still way off the mark for instantaneuous showering.
Most of the previously mentioned makes and models in the thread will also provide a small quantity of hot water after a few minutes, simply due to the stratification caused by convection of hotter water rising to the top of the tank, so its not really new or ground breaking performance. After few minutes of heating the initial burst of hot water will not be maintained at that temperature, as they all use displacment of hot water by cold to deliver the flow. The introduction of the cold water rapidly disturbes the stratifiacation and mixes the hot with cooler water lowering the output temperature. The longer the heater is on the more bulk of hot water is available so the cold dilution rate is slower.
You are then limited by the heat input rates, which for the reason already given cannot provide enough instantaneous hot water.
I find that turning on the water heater as soon as you get on site allows enough hot water to be generated to wash hands etc after you have done the essential steadies, and collecting water etc.
On the stored hot water theme you could simply follow the marine leisure route and fit a 24 to 40 litre calorifier. And compliment it with a domestic shower pump if the quality of the shower is of over riding importance to you.
http://www.webastomarine.co.uk/shop/vclose1.asp?prd=124037&cat=9741005823
http://www.webastomarine.co.uk/shop/vclose1.asp?prd=124037&cat=9741005823
John, I mentioned the Whale only as one you did not mention and the quickest, not suggesting it was instantanious just as fast as it gets legally in a touring van.
As for my figures, 22mins/13litres = 100 seconds per litre for round figures, which is well under the 2 minutes I mentioned, but also 5C less!, looks like the original set temperature then was slightly higher? taking more of that 2 minutes to reach.
But, if someone showers for 5 minutes, in that time several more cold litres have heated up, so given a short pause in the middle while 1st one dries off, enough water has been reheated for someone else to shower straight after, and again and again if required!
Not instantanious then but as far as a family is concerned, give or take continual perhaps?
Given what I do, this might be looked upon as hearsy! but I've had one since their beginnings, found it faultless now for what? 4 years? and does what it says very well
As for my figures, 22mins/13litres = 100 seconds per litre for round figures, which is well under the 2 minutes I mentioned, but also 5C less!, looks like the original set temperature then was slightly higher? taking more of that 2 minutes to reach.
But, if someone showers for 5 minutes, in that time several more cold litres have heated up, so given a short pause in the middle while 1st one dries off, enough water has been reheated for someone else to shower straight after, and again and again if required!
Not instantanious then but as far as a family is concerned, give or take continual perhaps?
Given what I do, this might be looked upon as hearsy! but I've had one since their beginnings, found it faultless now for what? 4 years? and does what it says very well
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