Inline water heater

[Grey13]

In order to increase shower water supply, considering that the Truma Ultrastore is only 10 liters, has anyone added an inline water heater to supplement supply? Perhaps something like this? https://www.zipwater.co.uk/shop/hot-water/zip-inline-instantaneous-hot-water-heater-3kw-es3

 

[otherclive]

We rarely use the caravan shower but when we do find the ultra store sufficient. It’s water is hot enough that when mixed with the cold supply it’s temperature is fine for a shower. If two of us are showering I put the heater setting to high power electric plus gas, so it only takes a short while to come back to temperature.
Of course we don’t use the shower in the same manner as a site shower, more like a ‘submariners “ shower.

A zip heater at 3 kw seems pretty high for caravan usage and apart from giving a longer period of water supply from the aqua roll or hose connected service point I don’t think you would see any significant difference to using the caravans own shower and ultra store.

The 28 page book on zip heaters concentrates the lower power one on hand washing usage not showers.

 

[Gabsgrandad]

At 3kw you couldn't use it on a lot of sites, a lot of private sites including cls run 10 amp. supplies.

 

[ProfJohnL]

In order to increase shower water supply, considering that the Truma Ultrastore is only 10 liters, has anyone added an inline water heater to supplement supply? Perhaps something like this? https://www.zipwater.co.uk/shop/hot-water/zip-inline-instantaneous-hot-water-heater-3kw-es3

Hello Gray,

I doubt whether any touring caravanner has fitted anything like the heater you link to for a number of reasons.

In particular the units specification calls for a minimum water pressure of 2Bar which is already greater than the 1.5Bar for caravan pipework can handle.

It has an electrical load of 2.8kw, which is going to cause problems on some sites with limited current capacity.

Caravan showers will use water at a rate of about 3L per minuet. Typical water temperatures are about 38C. An instantaneous heater would need to raise 3L of cold water to about 38C per minuet. Or 1 litre per 20 seconds.

To put this into perspective, I put 1 litre of cold (7C) water into my 3kw kettel and timed it to 38C (Measured with a fast response laboratory grade thermocouple) it took 53 seconds. Even allowing for the thermal mass of the kettle (Plastic) it still takes twice as long to raise the water temperature to shower temperature. And that rings true when you consider the smallest domestic electric shower is 8.5Kw and the flow is barely enough for a decent shower.

So in reality such a device would not add a great deal to the effectiveness of the shower.

 

[Grey13]

Thanks prof. I am aware of the 2 bar issue that is why I said “like” the one shown. Anyway I just asked to see if I could get any informative replies from people that may have done something like this. For health reasons I simply cannot use public facilities. Enough said. For the discussion purposes it is not too difficult to calculate the amount of energy/power required to do this and yes based on time restrictions of a shower say 4 or 5 minutes, it looks impractical. By way of general discussion, we start with the S (specific heat) of water, which is 4.184 J of heat that is required to raise temperature of 1 g of water by 1 ℃ it means that 4.184kJ of heat will be required to raise the temperature of 1 kg of water by 1℃. 1 kg = 1 liter. So lets see, we take 4180 x volume (10 kg or 10 liters) to be raised from say your 7 deg C to say 30 deg C and give ourselves a time limit of say 3 minutes per shower. Bearing in mind at the outset we have 10 liters from the truma already at 70 deg C to cope with the first 4 or 5 minutes of the shower. That means we will need 961400 joules. (temp rise is 23 deg C) The formulae to convert joules to watts is power = energy / time. So bottom line we will need 4kw to do the job. Too high as you pointed out. When speaking to a Truma engineer he said the most common solution was to add a second heater/storage vessel in front of and feeding the truma. If you added a second 10 liter unit that could take 20 or 30 minutes to heat the water to say 60 deg C it would use a lot less power and not make a dent on the site supply, which is what will now have to start looking at.

 

[Grey13]

http://www.rainbow-conversions.co.uk/heaters-motorhome-caravan/propex-10-litre-electric-water-storage-heater.html

 

[otherclive]

Thanks prof. I am aware of the 2 bar issue that is why I said “like” the one shown. Anyway I just asked to see if I could get any informative replies from people that may have done something like this. For health reasons I simply cannot use public facilities. Enough said. For the discussion purposes it is not too difficult to calculate the amount of energy/power required to do this and yes based on time restrictions of a shower say 4 or 5 minutes, it looks impractical. By way of general discussion, we start with the S (specific heat) of water, which is 4.184 J of heat that is required to raise temperature of 1 g of water by 1 ℃ it means that 4.184kJ of heat will be required to raise the temperature of 1 kg of water by 1℃. 1 kg = 1 liter. So lets see, we take 4180 x volume (10 kg or 100 liters) to be raised from say your 7 deg C to say 30 deg C and give ourselves a time limit of say 3 minutes per shower. Bearing in mind at the outset we have 10 liters from the truma already at 70 deg C to cope with the first 4 or 5 minutes of the shower. That means we will need 961400 joules. (temp rise is 23 deg C) The formulae to convert joules to watts is power = energy / time. So bottom line we will need 4kw to do the job. Too high as you pointed out. When speaking to a Truma engineer he said the most common solution was to add a second heater/storage vessel in front of and feeding the truma. If you added a second 10 liter unit that could take 20 or 30 minutes to heat the water to say 60 deg C it would use a lot less power and not make a dent on the site supply, which is what will now have to start looking at.

There is also the efficiency factor to take into account when heating moving water in a pipe.

 

[otherclive]

I had a Propex caravan heater gas/electric and a Propex water heater fitted in my Trigano Silver they were well made pieces of kit with good technical support from Propex too. Can’t recall if the water heater was the same as above. Seem to think my kit was for marine use originally and were fitted either by the importer or previous owner. But they worked fine.

 

[Dustydog]

Grey,
Caravanning is all about sensible domestic alterations.
Rather than a full blown 10 minute deluge you go for a quick splash and dash.
A quick few second wetting. Lather up including hair. Rinse off in circa 30 seconds . Piping hot and more than enough. 10 minutes later SWMBO will follow, extending the times and more than happy. And there is still hot water left.
What you propose is not a great idea. However don’t forget your Ultrastore also runs on gas which can be used to great efficiency.

 

[Kevin2306]

We do the same as Dusty without any bother at all, can’t see the point of having a built in facility and not using it tbh.

Kev

 

[Hutch]

We do the same as DD and Kev, normally i take the dogs for a walk, whilst the boss has a shower and when I come back 10 to 20 minutes later depending on the rain, the water is hot again, and whilst Breakfast is being prepared if not BBQing then I have my shower. And we have ours powered on gas and electric at all times, heats the water quickest.

 

[Grey13]

NOTE: After being called out by a moderator over this response I unreservedly withdraw it and apologize.

Thanks for all the information about personal habits when using van showers however I asked a technical question about water heating and luckily have had at least 2 relevant answers. Thanks!

 

[Damian]

Thanks for all the information about personal habits when using van showers however I asked a technical question about water heating and luckily have had at least 2 relevant answers. Thanks!

Is there any need for this reply?
You asked a question to which you have had various replies posted with the intention of helping you.
If this is the "thanks" you give maybe you should set your question with strict reply parameters.
This kind of post will not give anyone the incentive to help in future requests.

 

[Grey13]

Have fun folks!

 

[Grey13]

Hi Dusty, actually my response that solicited Damian's harsh telling off was in response to your comment. Quote; Caravanning is all about sensible domestic alterations. I guess I was being over sensitive at the time and felt it implied that by wanting additional hot water I was being "unreasonable", as opposed to "sensible" . As it turns out when talking to a Truma engineer they get many similar requests and generally recommend something typical of the unit I posted above. ( www.rainbow-conversions.co.uk/heaters-mo...-storage-heater.html ) On reflection I realized it does not pay to be that sensitive and for what it's worth, I should adopt my "twitter" protocol when using this platform and realize everyone has opinions and it is not up to me to say they are right or wrong or for that matter judge them or even react to them. Each one to his/her own!
I called Damian's response harsh because IMO his comment was a little snide suggesting "setting "parameters" and "if this is the thanks you give" were equally uncalled for. I do however understand that when he made the comment he felt I was having a go at innocent well intended responses regarding how people cope with the limited hot water supply, even though they really had little to do with my question. I hope that clarifies my actions and we can let it all go, after all no one is perfect!

 

[Raywood]

Having read through the posts I would agree with those who feel the additional capacity is not needed.
A problem for me with the extra tank would be filling it. You would be using the capacity of the water carrier and need to fill it again as soon as you put the water on on site. The weight of the water would mean in most cases you would need to drain the tank before moving as it could easily take you over the MTPLM if this is not done, and all that water on a pitch might flood it or make it very muddy.

 

[Dustydog]

Hi Dusty, actually my response that solicited Damian's harsh telling off was in response to your comment. Quote; Caravanning is all about sensible domestic alterations. I guess I was being over sensitive at the time and felt it implied that by wanting additional hot water I was being "unreasonable", as opposed to "sensible" . As it turns out when talking to a Truma engineer they get many similar requests and generally recommend something typical of the unit I posted above. ( www.rainbow-conversions.co.uk/heaters-mo...-storage-heater.html ) On reflection I realized it does not pay to be that sensitive and for what it's worth, I should adopt my "twitter" protocol when using this platform and realize everyone has opinions and it is not up to me to say they are right or wrong or for that matter judge them or even react to them. Each one to his/her own!
I called Damian's response harsh because IMO his comment was a little snide suggesting "setting "parameters" and "if this is the thanks you give" were equally uncalled for. I do however understand that when he made the comment he felt I was having a go at innocent well intended responses regarding how people cope with the limited hot water supply, even though they really had little to do with my question. I hope that clarifies my actions and we can let it all go, after all no one is perfect!

Thanks for all that Grey.
A lot of the answers given on here may seem a bit cutting futile or pedantic but you have to remember a lot of us are old lags at this game and grew up the hard way with next to no comforts that are common place today. My reference to "sensible" was not a criticism of your thoughts but more so to help any of the Newbies understand that main stream caravanners have to make adjustments to their ablutions to enjoy their caravan.
Whilst I'm all for modifications I am against trying to replicate home equipment at expense of eating into my payload or using inordinate amounts of site electricity.
Our Damian's bark is worse than his bite . He has spent considerable man hours over the years doing a fine Moderators job which sometimes can be a thank less task. Please continue posting and enjoy the Forum :cheer:

 

[Icaru5]

I agree with Ray, Dusty and the others and we employ similar techniques when performing our morning ablutions in our beloved Caravan. I think the temperature, flow rate and quantity of hot water provided by the standard fit on-board Truma water heater is more than adequate.

After all, a quick, yet perfectly adequate and invigorating shower is hardly a major inconvenience, and when standing on a trailer in the middle of a field one can’t really be expecting to have the same experience as provided by their mains-fed Worcester 37CDi back at home. *

Other domestic Combi-Boilers are available

 

[gary]

Well don't know what to say, personally I'm with the adjustment to habit but I note your reason for not using site facility which may then come down to time factors causing the need for more hot water?.

So Truma's 'advice' is one way of selling another heater but no mention they make a 13lt as well?
Personally I've got the Whale 13lt with duel 600w heating elements plus gas of course, this lot together reheats water quite rapidly and allows we both to take showers within a few minutes of each other.
Heating 13lt from 15C to 70C is 22mins so can add 5lt more while taking 8.5 min shower.

PS, I've also got an onboard cold tank which further reduces heating times

 

[Craigyoung]

Well I am yet to use my caravan shower as I have not had a problem with the on site facilities we use and I like at least a 2o minute plus shower so I can just chill out stand and relax ( no comment from Lc either ) !

 

[Grey13]

I guess I should hope and acknowledge that all these comments about "how to cope with inadequate van shower facilities" as if I am ignorant of the issues they pose in the first place, when what I really asked about was ideas from anyone that has increased their capacity, are all made by people that are not aware that due to personal health reasons I cannot use public facilities. (Well without risk to my well-being)( Not sure why I am forced to reveal that either by a continuing barrage of posts telling me how to cope rather than modify) Astounding how indifferent some are to a fellow humans situations and needs. May I suggest everyone now stops trying to convince me additional capacity is not needed, I can assure you that I get it that for normal people who can use the on site facilities it is probably not necessary but you should also get it that if for special personal reasons if someone wishes to increase their capacity it is not for the whole platform to pound me with alternative suggestions and try and convince me otherwise. I GET IT FOLKS!

 

[Craigyoung]

Sorry !
You are right . Didn't realise .

 

[Icaru5]

Come on now Craig, We’ve already had words about this ! :evil:

 

[Craigyoung]

Come on now Craig, We’ve already had words about this ! :evil:

:lol: !!

 

[otherclive]

Well I am yet to use my caravan shower as I have not had a problem with the on site facilities we use and I like at least a 2o minute plus shower so I can just chill out stand and relax ( no comment from Lc either ) !

You must tell me which sites you frequent so I and other don’t have to stand around waiting for shower cubicles to come free