[CleanerCarpets]

Thinking of installing an immersion heater in my van water tank to warm the water before i go out in the morning.

I've been looking at the window guys threads and there is plenty on there about not using 3kw immersion heaters without having 16a cable and connections and a separate 16a plug connected on its own cable to the house fuse board and a 16a fuse.

But looking at portables they have a 3kw heater on board which is on a 13a standard plug connected obviously to the customers normal plug socket.

So how is that safe but a 3kw immersion isnt when just used for an hour or so to preheat a tank?

And 2x 1500watt vacuum motors use one 13a plug too?
 

[john martin]

Thinking of installing an immersion heater in my van water tank to warm the water before i go out in the morning.

I've been looking at the window guys threads and there is plenty on there about not using 3kw immersion heaters without having 16a cable and connections and a separate 16a plug connected on its own cable to the house fuse board and a 16a fuse.

But looking at portables they have a 3kw heater on board which is on a 13a standard plug connected obviously to the customers normal plug socket.

So how is that safe but a 3kw immersion isnt when just used for an hour or so to preheat a tank?

And 2x 1500watt vacuum motors use one 13a plug too?

16amp cable would just refer to the thickness rating of the copper wire  ,  as in ' standard ' cable that u see on you machine or kettle lead is 1.5mm or 16amp rated . 
Thicker 2.5mm cable would be rated at about 25amps .

They are just saying dont use very thin cable , of 1mm or so ( which u dont see much of really )

The plug fuse on the other hand is a thin bit of fuse wire designed to get warm when 13amps is put through it ... although the wire may not melt and break the connection for several more than 13 amps .
I think it was mostly put there way back to protect houses that may have been wired with thin cable in the early days of house wiring .

the immersions rated 3kw are likely 12 amp 2.8kw as manufacturers have by regulation to keep under  13amps
The two 1500w 7amp motors and pump on one cord thing you will not find coming from a manufacturer ....  but most who have done it themselves will tell u its ok in general ...   the plug might start to get a bit warm (not hot ) as the plug fuse wire heats ... but it shouldn't affect anything in the house wiring as that would be rated for a higher current .

[Robin Ray]

3000 w divided by 240 v = 12.5 amps .... no probs.

Its just a big kettle, and they run off of a 13 amp fuse and cable.

[CleanerCarpets]

yeah they are saying kettles are ok as they run for short times

so i am thinking good cable, 13a plug and rcd would be ok for shortish times to prewarm a tank

[Mike Halliday]

I have an immersion element fitted in my water tank and preheat the water over night, which is also great in winter as it acts as heater to stop everything freezing.

My tank is an old Bane stainless steel tank which has the fitting for the element built in on construction.

If you insulate your tank it will stay warm all day, although my tank is also plumbed into the van radiator so as I drive it heats the water

[CleanerCarpets]

yea Mike the tanks that heat from the van as they drive are really useful

i think the elements in those are smaller than 3kw but i wouldnt be sure

problem is the standard is 3kw and the elements are cheap enough, the ones like 2.4kw etc are non standard and are expensive

i think i'll plumb a 3kw in and see how i get on - my old Alltec machine had a 3kw heater on it i think and i never had an issue with that tripping standard plug sockets

if i use a 13a rcd on the plug and it trips all the time i'll know i have a problem

[Mike Halliday]

The elements are the same as fitted in domestic water immersion cylinders, mine blows every couple of years so I have to replace it, just buy one from wickes.

They have a thermostat fitted so you can set it too any temp you like, which is useful for overnight heating.

I used to plug it into customers houses while I did all the set and prespraying to give the water a bit of a boost

[CleanerCarpets]

thats what i am thinking, prewarm before set off, top up on job

thanks - i'll get it done next week

Toolstation are good as they have all you need including the flanges and drill holes

[Lewis Newby]

Sounds interesting, would you mind posting some pics up of how you set it up/install. I have been thinking of doing this for years as we still do a little car valeting and in the winter that water gets COLD!

[Shaun_Ashmore]

How much water are you carrying?

Mike said and I agree that to heat a decent amount of water you do have to give it a lot of time more than a few hours to get it hot driving around with the heated water from the radiator won't do it alone.

Shaun

[CleanerCarpets]

i have a 175 litre tank but i dont use anywhere near that in a normal day

so i will just have about half full and see how the temp goes and how long it takes to warm, only want it about 50 degrees C and if i insulate the tank well it will keep warm fairly well with tops ups on route

i met an oven cleaner not so long back who does the same and his water was still really hot in the afternoon - won't cost too much to heat but i'll have a play and see and post some piccys when its done

[CleanerCarpets]

ok, fitted the immersion this weekend - if anyone is interested let me know and i'll post whats needed (all from the same place) and how to do it

[SimonW]

   would be nice if you could drop pics and let us know what's necessary.
Thank you and looking forward to see how it looks like!

[CleanerCarpets]

ok, i got all the bits from Toolstation - i used them as they had everything i needed and good prices.

I used a 27inch long like immersion heater (comes with fibre washer)
Immersion heater flange to secure on the threads on the inside of the tank
Immersion box wrench to tighten
10 piece holesaw set
16a plug
One metre of immersion cable
Fly Lead Socket Convertor 13A Lead to 16A Socket
Another fibre washer for the flange


If you put these codes into Toolstation website it'll bring them up so you can see what i used even if you use another store it helps see what i am on about. Codes are - 65632, 36175, 89357, 23014, 80367, 31429, 47166, 73273 - comes to just under £50

I used 16a immersion cable and plugs - the final plug converts to a normal 13a plug. Just means the final cabling going to the immersion is 16a rated and if i ever want to run a 16a socket from my home fusebox i can.

Obviously drill a hole with the biggest holesaw in that kit at the lowest point you can in the tank - the element needs to be off any plastic on the sides or bottom and have a safe distance so it wont melt anything. The kit i bought has a 64mm holesaw - you actually need 65mm so i had to file down the hole a mm to get the immersion through. I bought the kit as its cheap and comes with the drill arbour thing but obviously a 65mm holesaw is easier!

Then sand down the rough bits where you have cut through in the tank to make a good seal for the washers. Put the immersion through the hole and attach it with the flange on the inside of the tank (make sure you have a fibre washer on each side. The main problem is the threads on the immersion heater arent very deep, so when you out it through the tank there is very little threads showing on the inside. What i did was use Boss White (the green eco one) on the threads and on the washers - that really helps stop any leaks getting through and also lubricates it so when you nip the threads you will find it easier to tighten. Obviously use the box immersion wrench to tighten it up on the outside and i used mole grips to stop the flange on the inside spinning.

Because the threads are so limited i did it first time without Boss White but with just the fibre washers it weeped very slightly - the Boss White sorted it when i did it again. I'll post the piccys underneath this from my phone - you will see the Boss White around the immersion (the green paste stuff)

Then i filled the tank to make sure i had no leaks (then emptied it again!) before wiring the cable onto the immersion and plugs.

I ran a heavy duty 13a extension cable from a garage plug and ran the immersion for 2 hours to test, i had an RCD adapter on the garage plug end. The cable never got hot and all the plugs were ok - not overheating at all. The RCD didnt trip so nothing was melting to short etc. Like i say, portables run 3kw immersions all the time on just 13a connections so i am thinking so long as its relative short times you have it plugged in you should be ok. A couple of hours in the morning and tops ups during the day should be fine.

I wouldnt leave it plugged in over night though on a timer just in case it did start to run the cables hot.

Any questions let me know - and obviously if you have a go be careful - water and electrics go bad together!!

[CleanerCarpets]

[john martin]

nice work , 16amp plug/socket not needed ? ... as u still have a 13amp fuse in the plug u plug in .

[Mike Halliday]

Looks a  good fit,  How do you think this fitting will react to the constant contraction and expansion of the heat on a plastic tank?

How big is the tank? It takes 4hrs to heat 80gl to a reasonable cleaning temp'  you need to fill it and heat it too near boiling to give the seal a proper test.

I ran mine off a timer to turn on & off through the night to give the cable etc time to cool down rather than run it for 5 hrs straight
 

[CleanerCarpets]

I ran 16a on the tank end just in case i thought the cable was getting too hot and then i would have a 16a plug put in on its own ring from the house fusebox to run at my house, but 13a looks like its coping ok

The tank is 175 litres, i am putting about 100 litres in and after 90mins the water is a good temp, i am not bothered about it being upto 60 degrees, its just better than rinsing with stone cold water in the winter.

The tank has a lid fitted with a hole in the top where an adapter fits for things to thread through it. I've taken out the adapter and filled the hole with a high density foam bung which i have inserted a plastic tube through - acts as a little chimney to help with the air warming and trying to bulge out the tank but stops too much air getting in to cool the water. I need now to insulate the tank and i'll see how it goes - it was just a little job to get warm water on jobs for rinse without using customers tap - i just drop the Airflex tales in to the tank. If i want to use an in tank rinse or product i have a pump from the tank that will fill the tank on the Airflex and i can put the additive in there without putting it in all the big water tank.

I find most jobs rinsing with warm water is ok as i always prespray and agitate well and don't find i need scorching hot rinse water. But stone cold water from a tank on the van is crap to work with and brings the temp of the carpet way down before it can start evaporating off.

To run the 3kw heater for 2 hours in the morning before setting off will cost about 90p and just costing £50 to fit i think its worth a go.

Will have to see if the chimney helps with the tank getting warm and cold and the immersion was a really tight fit so see how its goes. Boss White helps as well.

If i see my van leaking from the back tomm i will know why 

[SimonW]

Looks solid.  Great work mate. Surely I will get one as well. Thanks for exhausting  explanation!

[Lewis Newby]

ok, fitted the immersion this weekend - if anyone is interested let me know and i'll post whats needed (all from the same place) and how to do it

Yes please mate, have a refit in mind shortly where I plan to rip it all out, hammerite and protectakote the floor and re ply/possible carpet along with a new water tank and some new bits of kit,  a heating system would be good.

Wondered about a lower powered heater running off an inverter during the day?? Not technically minded so not sure if feasible