[nathankaye]

Legionnaires disease is with stagnant water as well. The water in your tank that your heating is only stagnant during the night whilst it is heating/warming. During the working day it is nothing like stagnant water.  Also I believe you need to have particles ie rust for an example in your tank for it to latch onto.
So in the case of us window cleaners using pure water heated in a tank and drove around for work.... It is a risk which is extremely unlikely to occur

[paul alan]

Its working, I can tell thanks to peavey as the lecy meter is blinking twice as fast now.

[֍Winp®oClean֍]

Its working, I can tell thanks to peavey as the lecy meter is blinking twice as fast now.

My advice is be reasonable with your expectations. You're not going to have steaming hot water hitting the glass unless you literally boil the tank- which would take a very long time. However, if you leave your van tank uninsulated it will act as a giant radiator and nothing in your van will freeze- regardless of outside temps. Also, your whole system, hoses etc will remain lovely and supple all day. For me the above is more beneficial than a "on-demand" diesel heater but.... the immersion IMO is not a realistic replacement for a proper hot water system. However, it does keep you working comfortably all winter with no freezing issues.👍

[alank]

You couldn't call my water stagnant the way I drive.

[Seymour Sunshine]

So should we all be adding bleech to our water now?

No! Not all. And nowhere does it say "all."

But if you're holding your water at above-ambient temperatures for long periods and you want to be safe rather than sorry, then it makes sense to take all possible precautions. Did you deliberately misunderstand or are you simply taking the excess water from well-meaning people's kidneys?

[dazmond]

Every year it's the same old fears about legionnaires disease.does anybody know of any window cleaner who has ever  contracted it?..... No I didn't think so.

That's because we don't store water above 20c for long periods of time.thats when it COULD breed.not when your heating water to use the very next day.

[alank]

Not at all taking the p, at this time if year heated water used and re filled daily. more bothered If water left in tank during summer when temperatures are higher anyway.would it then be beneficial to bleech?

[Dry Clean]

1. Even with the variables its very easy to work out heating times.
2. As we have little or no nutrients in our pure then the risk of Legionella is virtually non existent.

1 - I'd be very interested to see how you do your calculations. Heat in is no problem: Q = VIt. But how do you calculate the heat losses? It comes to a very nasty differential equation with an exponential solution. And you have to make many assumptions about conductivity and emissivity. If you can do that, you're a better mathematician than I am. ... which, of course, you might be.
2 - In that case, why do we have algae growing in our IBCs?

I'd be very wary of saying that the risk of spreading a deadly disease is virtually non-existent when you are warming and cooling large quantities of water repeatedly and then spraying it onto people's houses.

If a window cleaner can work out conductivity & emissivty then he shouldn't be a window cleaner!

Why is it some people aren't happy unless they're making the easiest of things as hard as possible, if you want to work out
how long it will take to heat your water there's a calculator, this will give you the maximum temp possible in the time available,
I'm sure there will also be one for heat loss but as we aren't trying to get our water to an exact temp then if you allow minus 5 to 10degrees you wont be far away.
As for Legionella, considering the amount of people who have been heating and storing hot water over the years without a single
outbreak plus all the other factors then the evidence points to it not being of any concern.

[Seymour Sunshine]

Why is it some people aren't happy unless they're making the easiest of things as hard as possible, if you want to work out
how long it will take to heat your water there's a calculator, this will give you the maximum temp possible in the time available,
I'm sure there will also be one for heat loss but as we aren't trying to get our water to an exact temp then if you allow minus 5 to 10degrees you wont be far away.
As for Legionella, considering the amount of people who have been heating and storing hot water over the years without a single
outbreak plus all the other factors then the evidence points to it not being of any concern.

My input, which has been made with no other motivation than to be helpful and useful, can be simplified (without losing anything of importance) to:

* An immersion heater is a far more energy-efficient way of keeping the water in your van tank from freezing than using a space heater.

* Heating and cooling water over long periods could lead to a buildup of potentially dangerous levels of highly toxic legionella.

What is hard about that?

[paul alan]

Why is it some people aren't happy unless they're making the easiest of things as hard as possible, if you want to work out
how long it will take to heat your water there's a calculator, this will give you the maximum temp possible in the time available,
I'm sure there will also be one for heat loss but as we aren't trying to get our water to an exact temp then if you allow minus 5 to 10degrees you wont be far away.
As for Legionella, considering the amount of people who have been heating and storing hot water over the years without a single
outbreak plus all the other factors then the evidence points to it not being of any concern.

My input, which has been made with no other motivation than to be helpful and useful, can be simplified (without losing anything of importance) to:

* An immersion heater is a far more energy-efficient way of keeping the water in your van tank from freezing than using a space heater.

* Heating and cooling water over long periods could lead to a buildup of potentially dangerous levels of highly toxic legionella.

What is hard about that?

Granted seymor, and I do appreciate your input as its best to be safe than sorry.

But I think the point is, its a different fresh tank of water each day. As long as being careful it shouldn't pose a problem.

Thanks for your input as its good to have your thinking tested by others.

[paul alan]

Its working, I can tell thanks to peavey as the lecy meter is blinking twice as fast now.

My advice is be reasonable with your expectations. You're not going to have steaming hot water hitting the glass unless you literally boil the tank- which would take a very long time. However, if you leave your van tank uninsulated it will act as a giant radiator and nothing in your van will freeze- regardless of outside temps. Also, your whole system, hoses etc will remain lovely and supple all day. For me the above is more beneficial than a "on-demand" diesel heater but.... the immersion IMO is not a realistic replacement for a proper hot water system. However, it does keep you working comfortably all winter with no freezing issues.👍

And this is the main reason I have completed this project today, frost prevention.

I would imagine if at some point I did want piping hot water at the brush head and I did install one of them water heaters it would use less fuel to get the water up to temp if the immersion has pre-heated the water.

Kind of like these new hybrid engines, dual fuel's to achieve a "hot" outcome.

[nathankaye]

 But initially i wanted hot water, for cleaning and mostly for the softer hoses. To that affect I started by using 500watt fish tank heaters submerged in my tank. I was able fo get into the 40's using them overnight. Now that was great for warming up the hose and I started to see a difference in cleaning as well and that set me off wanting hot water and deciding upon the Immersion heater route to get it.

So basically im saying, that once youve seen the benefits and advantages of using hot you may not have the main aim of only doing so to keep the frost at bay.
( I think the ones who say that after a long time using it, is because of the running costs of doing so.)

[Jonny 87]

But initially i wanted hot water, for cleaning and mostly for the softer hoses. To that affect I started by using 500watt fish tank heaters submerged in my tank. I was able fo get into the 40's using them overnight. Now that was great for warming up the hose and I started to see a difference in cleaning as well and that set me off wanting hot water and deciding upon the Immersion heater route to get it.

So basically im saying, that once youve seen the benefits and advantages of using hot you may not have the main aim of only doing so to keep the frost at bay.
( I think the ones who say that after a long time using it, is because of the running costs of doing so.)

Nathan it would take about 18 hours to heat cold water of say 10 degrees up to 40 degrees.

Just in case someone reads this and decides to waste money on a 1kw heater.

The only way you could possibly achieve that is if regularly you have half a tank of water left from the day still warm, and your start temp will Gradually start to rise if that repeats for a few days.

For the average guy like me who nearly drains their tank every day, a 2kw is needed to get anywhere near that. Even then it will
Still need about 9 hours to get there.

This is a very accurate calculator of heat/volume/time.

http://www.jimsbeerkit.co.uk/calc.html

[nathankaye]

But initially i wanted hot water, for cleaning and mostly for the softer hoses. To that affect I started by using 500watt fish tank heaters submerged in my tank. I was able fo get into the 40's using them overnight. Now that was great for warming up the hose and I started to see a difference in cleaning as well and that set me off wanting hot water and deciding upon the Immersion heater route to get it.

So basically im saying, that once youve seen the benefits and advantages of using hot you may not have the main aim of only doing so to keep the frost at bay.
( I think the ones who say that after a long time using it, is because of the running costs of doing so.)

Nathan it would take about 18 hours to heat cold water of say 10 degrees up to 40 degrees.

Just in case someone reads this and decides to waste money on a 1kw heater.

The only way you could possibly achieve that is if regularly you have half a tank of water left from the day still warm, and your start temp will Gradually start to rise if that repeats for a few days.

For the average guy like me who nearly drains their tank every day, a 2kw is needed to get anywhere near that. Even then it will
Still need about 9 hours to get there.

This is a very accurate calculator of heat/volume/time.

http://www.jimsbeerkit.co.uk/calc.html

In the reference to fish tank heaters which you quoted, i believe my sentence was "heaters" as in more than one and anybody can use the search feature on here where in the past I said i used several heaters.
Fetching it forward, i promote the use of Immersion heaters as a great and safe way of achieving hot water, along with insulating the tank.   Perhaps i and others should state the obvious in saying "do your research and do so safely" but I thought common sense would prevail.
Now for me and the size of the tank and how much water I use, along with the different starting temps that I have then my immersion works pretty well and I achieve HOT water as shown in many of my vids on my channel. Ive also in the past said the reason I use a 1kw is because I currently rent and cannot mess about with the electrics.
In addition I had a private conversation with someone about immersion heaters and recommended a 2kw. In addition the heat calculators are  not truly accurate but give a good indication, because if they were right that would mean that I would have to come home, fill up and stick the heater on straight away. It would also mean that my electric bill would be extremely high and I certainly would not be running it through the summer montbs like I have been doing.

But, if I owned my own house I would be wanting the biggest and best heater I could afford to get. For me that would be a 3kw 27" inch long  element

[Seymour Sunshine]

I absolutely promise that this will be my last contribution to this thread.

The calculator mentioned is NOT accurate as it takes no account whatsoever of heat losses. I've had a look at the source code and all it does is to calculate the energy input and then calculate the temperature rise for a given mass of water. The heat loss would be very difficult to calculate since it depends on:

* surface area of the tank
* colour and surface texture of the tank
* material and thickness of the tank
* ambient temperature

and possibly some other factors I haven't considered.

It is absolutely wrong to think that twice the power will give twice the temperature rise or the same temperature rise in half the time etc. It is not anywhere near a linear relationship.

What is true to say is that the temperature will rise until the rate of heat gain from the heater is equal to the amount of heat lost by conduction, convection and mainly radiation. Then it will remain constant. A more powerful heater will get the water hotter and more quickly than a less powerful one. But please believe me, the physics is messy (and is the basis, believe it or not, for the early development of quantum mechanics) and the maths is horrendous!

To give you a flavour of the complexity of it:

* conduction depends on the thickness and surface area of the material and the temperature differences either side of the material
* convection depends on the surface area and orientation of the sides of the tank as well as the temperature
* radiation depends on the 4th power of the temperature difference, the colour and texture of the tank and the temperature and  area of the surroundings.

TBH all this isn't really that important. The important thing is that Paul has successfully installed an immersion heater and that he is aware of all the implications. As long as he reaches his goal of protecting his equipment safely, economically and with the least amount of messing about, I think he's done brilliantly.

[Jonny 87]

But initially i wanted hot water, for cleaning and mostly for the softer hoses. To that affect I started by using 500watt fish tank heaters submerged in my tank. I was able fo get into the 40's using them overnight. Now that was great for warming up the hose and I started to see a difference in cleaning as well and that set me off wanting hot water and deciding upon the Immersion heater route to get it.

So basically im saying, that once youve seen the benefits and advantages of using hot you may not have the main aim of only doing so to keep the frost at bay.
( I think the ones who say that after a long time using it, is because of the running costs of doing so.)

Nathan it would take about 18 hours to heat cold water of say 10 degrees up to 40 degrees.

Just in case someone reads this and decides to waste money on a 1kw heater.

The only way you could possibly achieve that is if regularly you have half a tank of water left from the day still warm, and your start temp will Gradually start to rise if that repeats for a few days.

For the average guy like me who nearly drains their tank every day, a 2kw is needed to get anywhere near that. Even then it will
Still need about 9 hours to get there.

This is a very accurate calculator of heat/volume/time.

http://www.jimsbeerkit.co.uk/calc.html

In the reference to fish tank heaters which you quoted, i believe my sentence was "heaters" as in more than one and anybody can use the search feature on here where in the past I said i used several heaters.
Fetching it forward, i promote the use of Immersion heaters as a great and safe way of achieving hot water, along with insulating the tank.   Perhaps i and others should state the obvious in saying "do your research and do so safely" but I thought common sense would prevail.
Now for me and the size of the tank and how much water I use, along with the different starting temps that I have then my immersion works pretty well and I achieve HOT water as shown in many of my vids on my channel. Ive also in the past said the reason I use a 1kw is because I currently rent and cannot mess about with the electrics.
In addition I had a private conversation with someone about immersion heaters and recommended a 2kw. In addition the heat calculators are  not truly accurate but give a good indication, because if they were right that would mean that I would have to come home, fill up and stick the heater on straight away. It would also mean that my electric bill would be extremely high and I certainly would not be running it through the summer montbs like I have been doing.

But, if I owned my own house I would be wanting the biggest and best heater I could afford to get. For me that would be a 3kw 27" inch long  element

No need to get defensive mate!

I’m with you on the immersion heaters, I used one for years. I just think your figures are out, perhaps due to you regularly having half a tank of water left, and so your heating up already warm water. That’s why I mentioned it, because someone like me who regularly drains their tank nearly empty, I would never achieve the same figures.

As of February this year you said you used 2 x 500watt heaters, that’s why it stuck in my mind, and that’s why I did the figures of 1kw of power taking 18 hours to heat up. 

[Dry Clean]

The heat calculator will give you the maximum heat achievable, that said because of heat lose obviously you wont get to the calculated level.
They are a handy tool though if you get guys coming on claiming to get all sorts of heat from underpowered immersions as they
do prove what its not possible to get.

[AuRavelling79]

Further back I was asked about my thoughts on legionnaires.

Short answer - don't believe it to be a possible problem.

Long answer - as to why I believe that.

My tank heating is primarily for frost protection and supple hoses in cold weather. Rarely I want warmer water for a dirty first clean but no more than a few times a year.

So typically I will heat the water for 4 to 6 hours at some point between 6pm the night before and 8 am on the day I drive off. Typically I do not bother if the temperature outside will be above ten degrees celsius and the water in my tank above about 12 degrees.

Let's give a typical situation when I will use warm water - like last week when daytime temps were about 7 degrees and night time about 0 to 2 degrees.  So I think "bit nippy lets put in four hours of heat" into 400 litres of water.  At 10 pm the water in my tank is about 10 degrees and in the morning it's about 30 degrees.

I go to work and use, say 350 litres and at the end of the day (3/4pm) the temperature of the remaining water is 20 degrees. By 10pm it's about 12 degrees.

So I think "what's the weather from now 'til tomorrow? Milder - less or no heat - maybe an hour or two in the morning from 6 am. Colder? Give it another 4 hours. What's the water temp in my insulated main storage tanks? (usually five/ten degrees higher than ambient in the winter)

Not an exact science - but the hottest temp in my van tank will be 40 degrees in the morning, back to 20 degrees by bed time and less when I add water from my storage tanks.

So when and how long is my water at 20 to 40 degrees? 3 hours - during final heating time. (say 6 am to 9 am.)  Followed by six/seven hours dropping to the 20's when either it will be topped up with cooler water
or if not working the next day it will be below 20 degrees by bed time.

So the absolute maximum the water can be at 20 to 40 degrees is about fifteen hours. Then it will be replaced/topped up or sit at a cooler temperature.

So I don't worry.

[alank]

Thanks gold

[paul alan]

Nice warm van this morning!