[paul alan]

Today I will be installing an immersion heater into my tank.

I am putting a 16a mcb in the consumer and from that I am going into a 16a timer that will go on the wall next to the consumer unit then drilling through the wall to send a 2.5mm 3core cable(for outdoor use) to run down the wall which will connect to a 16a socket in my box I use for ro and booster pump.

I then have a 16a extension cord that will go through to the van and connect to the 3kw element that I hope still works or else I have a real pia on my hands taking it out and replacing as its near the bottom of a 650ltr wydale upright tank.

All going well I will have a nice hot tank of water in the morning.

Should I schedule some time breaks whilst on overnight ?  maybe 2 hours on 30 minutes off? or is this unnecessary as I'm using a full 16a setup?

I think I will order a temp sensor that I can drop into the tank as I have plumbers mate'd the lid shut to stop leaks from happening, so wont be able to take temp readings that way .

Can I expect leaky connectors etc now its all going hot?

[֍Winp®oClean֍]

Congrats on going about this the correct and safe way. Your set up is the same as mine.
No need for time breaks, I would start with 8 hours and see how you get on.
If the element is fitted to the tank via a mechanical flange (looks like a big brass nut which slightly bells out to a flat surface to meet the tank wall) then replacing the element is a doddle- simple as draining the tank, unscrew the old and screw a new one in.

[nathankaye]

Sounds good buddy, but yes you may find that all the connections may become loose. I definitely had to tighten and indeed change some connections.
Infact from my pump to the reel ive used a car radiator pipe as my reinforced plastic one, sprung a leak. I also have it fitted direct to my swivel connector and all other connections ive had to tighten, ie the filter before the pump has to be tightened many a times

[AuRavelling79]

As Peavey said. But ...

As it's a new install I would put it on and watch like a hawk for a couple of hours. If all is cool (as in joints and switches not getting over warm) then great!

Oh ... and make sure the water in the tank covers the element ... EVERY TIME. 

[Seymour Sunshine]

From your description, it certainly looks like you know what you're doing. Personally, I would put it on a timer. The temperature calculations are impossible to do as there are too many unknown factors, but a 3kW heater for 8 hours will consume 24 kWh.

You don't really want to be heating the water to very warm temperatures. There are rules about legionella regarding heating tanks of water. You are going to be spraying this water on several customers' properties every day. I'd be very wary of getting hot water in this way .. it's a serious disease.

This is taken from HSE: http://www.hse.gov.uk/healthservices/legionella.htm

What is legionella?
Legionella bacteria is commonly found in water. The bacteria multiply where temperatures are between 20-45°C and nutrients are available. The bacteria are dormant below 20°C and do not survive above 60°C.

My advice would be to just warm the water a little and keep the temperature well below the 20°C limit. Whatever you do, don't warm to water regularly to between the 20 and 45 limits. Hence use a timer.

[paul alan]

From your description, it certainly looks like you know what you're doing. Personally, I would put it on a timer. The temperature calculations are impossible to do as there are too many unknown factors, but a 3kW heater for 8 hours will consume 24 kWh.

You don't really want to be heating the water to high temperatures. There are rules about legionella regarding heating large quantities of water. You are going to be spraying this water on customers' properties. I'd be very wary of getting hot water in this way .. it's a serious disease.

This is taken from HSE: http://www.hse.gov.uk/healthservices/legionella.htm

What is legionella?
Legionella bacteria is commonly found in water. The bacteria multiply where temperatures are between 20-45°C and nutrients are available. The bacteria are dormant below 20°C and do not survive above 60°C.

My advice would be to just warm the water a little and keep the temperature well below the 20°C limit. Whatever you do, don't warm to water regularly to between the 20 and 45 limits. Hence use a timer.

I think water has to sit a certain temp for around 5 days before the bacteria can grow?

will be checking this out but thanks for the heads up!

[Seymour Sunshine]

Where a very serious disease like this is concerned, I would be very careful. The simple solution is to keep the temperature low, hence use a timer.

I had this idea and discussed this with my son who's a plumber. He jumped out of his seat and almost yelled at me not to do it for this very reason. There's a reason that window cleaners use an "on demand" system for hot water, and this is it.

It's an excellent way of keeping the water at a good operating temperature, but not for heating. Hence my suggestion of using a timer to limit the temperature rises. I guess that 15 minutes on and 2 hours off should be about right.

[Tony dunmall]

This a Main reason why I’ve NOT ventured down the line of an immersion as there is a small risk-unless you take precautions,emptying the tanks or part filling with cold to safety temperature then  flushing through the hoses then starting process again in morning of heating,as often I don’t use a whole tank

But correct me if I’m wrong, after reading much about the hot water threads recently. It seems that some companies have a return to the tank which will heat the water in the tank and I’m not talking about the froststat setting for during the early hours to prevent freszzing of Hoses and pumps

If this is the case and water is automatically recirculated to tank keeping heaters working constantly to maintain good health of heater

and some say by middle morning there tanks water are very Hot

This is no difference in my opinion than using an Electric element

So if this is the case then it’s scarmongering to keep people buying the more expensive heaters which companies are fitting

Just my thoughts

As I’m looking at fittings out the vans for Hot and it’s a high expense at minimum I’ve two vans maybe three that’s nearly 10K just for hot few months a year

[Susan Dean (1stclean)]

Where a very serious disease like this is concerned, I would be very careful. The simple solution is to keep the temperature low.

I had this idea and discussed this with my son who's a plumber. He jumped out of his seat and almost yelled at me not to do it for this very reason. There's a reason that window cleaners use an "on demand" system for hot water, and this is it.

It's an excellent way of keeping the water at a good operating temperature, but not for heating.

or not bother at all and just leave the tank empty from friday night until sunday when you start heating the water for monday ? this way it dies with the cold on a saterday meaning you can have the water any heat you want ?

[paul alan]

Where a very serious disease like this is concerned, I would be very careful. The simple solution is to keep the temperature low.

I had this idea and discussed this with my son who's a plumber. He jumped out of his seat and almost yelled at me not to do it for this very reason. There's a reason that window cleaners use an "on demand" system for hot water, and this is it.

It's an excellent way of keeping the water at a good operating temperature, but not for heating.

or not bother at all and just leave the tank empty from friday night until sunday when you start heating the water for monday ? this way it dies with the cold on a saterday meaning you can have the water any heat you want ?

good point!

I will be heating tank night before it gets used next day.

if there is anything left in it will get neutralised when I fill up with cold again when home.

There is a young ish fella up the street from me with a van that has legionella risk assessment written on the side, ill go and knock on for a chat soon.

Granville and Nathan , what are your thought's on this??

[paul alan]

Where a very serious disease like this is concerned, I would be very careful. The simple solution is to keep the temperature low, hence use a timer.

I had this idea and discussed this with my son who's a plumber. He jumped out of his seat and almost yelled at me not to do it for this very reason. There's a reason that window cleaners use an "on demand" system for hot water, and this is it.

It's an excellent way of keeping the water at a good operating temperature, but not for heating. Hence my suggestion of using a timer to limit the temperature rises. I guess that 15 minutes on and 2 hours off should be about right.

I am also a qualified plumber and as far as I can remember the water has to sit at a certain temp for a length of time to grow the bacteria, if the water is being heated and used on a daily cycle I see no problems.
but I will go and look into it further.

[Seymour Sunshine]

Where a very serious disease like this is concerned, I would be very careful. The simple solution is to keep the temperature low.

I had this idea and discussed this with my son who's a plumber. He jumped out of his seat and almost yelled at me not to do it for this very reason. There's a reason that window cleaners use an "on demand" system for hot water, and this is it.

It's an excellent way of keeping the water at a good operating temperature, but not for heating.

or not bother at all and just leave the tank empty from friday night until sunday when you start heating the water for monday ? this way it dies with the cold on a saterday meaning you can have the water any heat you want ?

good point!

I will be heating tank night before it gets used next day.

if there is anything left in it will get neutralised when I fill up with cold again when home.

There is a young ish fella up the street from me with a van that has legionella risk assessment written on the side, ill go and knock on for a chat soon.

Granville and Nathan , what are your thought's on this??

Yes, you're absolutely right to go have a chat with someone who really knows about this. I'm looking at things from a purely theoretical point of view as I have no direct experience or education in this particular field.

Just a point to bear in mind: the little sods are dormant below 20 deg. They aren't killed.

[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.

[paul alan]

Where a very serious disease like this is concerned, I would be very careful. The simple solution is to keep the temperature low.

I had this idea and discussed this with my son who's a plumber. He jumped out of his seat and almost yelled at me not to do it for this very reason. There's a reason that window cleaners use an "on demand" system for hot water, and this is it.

It's an excellent way of keeping the water at a good operating temperature, but not for heating.

or not bother at all and just leave the tank empty from friday night until sunday when you start heating the water for monday ? this way it dies with the cold on a saterday meaning you can have the water any heat you want ?

good point!

I will be heating tank night before it gets used next day.

if there is anything left in it will get neutralised when I fill up with cold again when home.

There is a young ish fella up the street from me with a van that has legionella risk assessment written on the side, ill go and knock on for a chat soon.

Granville and Nathan , what are your thought's on this??

Yes, you're absolutely right to go have a chat with someone who really knows about this. I'm looking at things from a purely theoretical point of view as I have no direct experience or education in this particular field.

Just a point to bear in mind: the little sods are dormant below 20 deg. They aren't killed.

Dormant is fine with me.

[Seymour Sunshine]

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.

[tony day]

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!

[paul alan]

All fitted and ready to go.

All wired up according to the regs, I just hope that when I turn it on the element is still working.

Just waiting for some water to fill so I can test it.

on legionella:
A very effective chemical treatment is chlorine. For systems with marginal issues, chlorine provides effective results at 0.5 ppm[citation needed] residual in the hot water system. For systems with significant Legionella problems, temporary shock chlorination—where levels are raised to higher than 2 ppm for a period of 24 hours or more and then returned to 0.5 ppm may be effective.[citation needed] Hyperchlorination can also be used where the water system is taken out of service and the chlorine residual is raised to 50 ppm or higher at all distal points for 24 hours or more. The system is then flushed and returned to 0.5 ppm chlorine prior to being placed back into service. These high levels of chlorine penetrate biofilm, killing both the Legionella bacteria and the host organisms. Annual hyperchlorination can be an effective part of a comprehensive Legionella preventive action plan.[31

Where does the legionella bacteria occur?
The bacteria causing the disease can be found in very small quantities in the ground, and in water and tap water. The legionella bacteria becomes a problem when it is able to multiply, e.g. in water with a temperature between 25o and 55o Celsius that is stagnant for a long period of time. A strong flow can prevent the growth of the bacteria, but if this flow is not constant throughout an entire hot water system, water could become stagnant in certain spots (so-called dead corners), where further growth could occur, creating a risk.

Controlling legionella bacteria
Legionella bacteria can multiply to dangerous concentrations in five days. A simple and effective way of controlling the bacteria in hot water systems, is to increase the water temperature. This will start to kill the bacteria at around 50ºC and if the water temperature reaches 60ºC and is held at that temperature for sufficient time (usually about 10 minutes), the bacteria will be killed. Satisfactory routine control of legionella bacteria will be achieved if a temperature of 60ºC is maintained throughout the cylinder for a period of one hour each day.
Heating the water to 60ºC will kill the bacteria but there is an increased risk of skin burns (scalding). Fitting a thermostatic mixing valve (TMV) allows the water to be stored and distributed at high temperature while blending it with cold water before it reaches the tap. (Building Regulation Part G required the fitting of TMVs as standard on baths in new homes.)
Water in storage cisterns should not be allowed to exceed 20ºC.

[֍Winp®oClean֍]

Easy way to tell if the element is working is to look at your electric meter- if it's working it will be flying round!!

[Seymour Sunshine]

All fitted and ready to go.

All wired up according to the regs, I just hope that when I turn it on the element is still working.

Just waiting for some water to fill so I can test it.

on legionella:
A very effective chemical treatment is chlorine. For systems with marginal issues, chlorine provides effective results at 0.5 ppm[citation needed] residual in the hot water system. For systems with significant Legionella problems, temporary shock chlorination—where levels are raised to higher than 2 ppm for a period of 24 hours or more and then returned to 0.5 ppm may be effective.[citation needed] Hyperchlorination can also be used where the water system is taken out of service and the chlorine residual is raised to 50 ppm or higher at all distal points for 24 hours or more. The system is then flushed and returned to 0.5 ppm chlorine prior to being placed back into service. These high levels of chlorine penetrate biofilm, killing both the Legionella bacteria and the host organisms. Annual hyperchlorination can be an effective part of a comprehensive Legionella preventive action plan.[31

Where does the legionella bacteria occur?
The bacteria causing the disease can be found in very small quantities in the ground, and in water and tap water. The legionella bacteria becomes a problem when it is able to multiply, e.g. in water with a temperature between 25o and 55o Celsius that is stagnant for a long period of time. A strong flow can prevent the growth of the bacteria, but if this flow is not constant throughout an entire hot water system, water could become stagnant in certain spots (so-called dead corners), where further growth could occur, creating a risk.

Controlling legionella bacteria
Legionella bacteria can multiply to dangerous concentrations in five days. A simple and effective way of controlling the bacteria in hot water systems, is to increase the water temperature. This will start to kill the bacteria at around 50ºC and if the water temperature reaches 60ºC and is held at that temperature for sufficient time (usually about 10 minutes), the bacteria will be killed. Satisfactory routine control of legionella bacteria will be achieved if a temperature of 60ºC is maintained throughout the cylinder for a period of one hour each day.
Heating the water to 60ºC will kill the bacteria but there is an increased risk of skin burns (scalding). Fitting a thermostatic mixing valve (TMV) allows the water to be stored and distributed at high temperature while blending it with cold water before it reaches the tap. (Building Regulation Part G required the fitting of TMVs as standard on baths in new homes.)
Water in storage cisterns should not be allowed to exceed 20ºC.

Well, there you go. Just a couple of teaspoons of bleach (bleach is about 5% free Cl) in the tank and you've got no worries at all.  But please check my calculation. That's what I love about this forum: we're a group of problem-solvers.

I hope my input was useful in some way. I'm genuinely trying to be helpful and supportive. If I come across as being a nit-picker, it's because I am! But I'm a good-hearted and generous nit-picker.

[alank]

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