[tomasxguty]

Been looking into hot water systems and what options are available.  I'd like the immersion heater way as a safe and economical option but since I don't have a drive way I am limited to either to gas or diesel heater installed in the van.

I was wondering if anybody tried to get one of those 18l portable lpg water heaters (like this one: https://www.ebay.co.uk/itm/18L-36Kw-Hot-Water-Heater-Gas-Lpg-Propane-Tankless-Instant-Boiler-Shower/263511304450?epid=23008908109&hash=item3d5a7f6902:g:HugAAOSwgNxajipR) and just run the water from and back to the tank using an appropriate pump.
I have 650l tank and was wandering how long it would take to bring temperature to around 60C simply by circulating water through the heater? I would insulate the tank properly so there is minimum heat loss. I'd run it for about 20 minutes in the morning while having my coffee and then just enjoy using hot water for the rest of the day without worrying about not forgetting to leave the van door opened to ventilate for example.

Do you think that 18l unit is powerful enough to make it work? Has anybody tried this and with what results?
Thanks for your opinion

[Smudger]

Do a forum search many are/have used these over the last 4 or 5 was ears
Darran

[tomasxguty]

Thanks Darran. I couldn't find any post that would be similar to what I am trying do to. Most people use either an immersion heater or small 5l gas heater that would warm water up as they are cleaning.
What key word would you use in the  search section please?

[Smudger]

Try searching l5 I don’t recall a specific thread but defo talked about however at 18 lpm will give you in theory 360 ltrs but as it returns to the tank it will mix with cold and you would lose all the heat quickly

We use immersion heaters and to get 650 ltrs of cold to a decent temp takes around 4 hrs overnight

I’m not sure you could raise the temp enough to be of use

Darran

[tomasxguty]

Thanks Darran, will do

[Dry Clean]

The heat in hot water is just stored energy so the important factor here is the Kw of your heater.
Going by the calculator. lets say your starting point is 10degrees and you want to raise it by 50degrees so
650litres by 50degrees by 36kw = just over 63minutes, if your flow is 18litres per minute then it will also be more than enough to cope. obviously add on a few minutes more for some heat loss while you're heating the water.

https://elementsofheating.wordpress.com/2012/09/26/how-to...

[tomasxguty]

Perfect. Exactly what I needed. Thank you for the reply and link.
So theoretically according to the calculator if I need to warm up 400l of water to 45C from 10C using 37kW heater it would only take around half an hour. That is enough water for one operator for a day. Amazing.
That means I won't have to even carry a propane bottle in the van.
Will try it and let you know how it goes.
Thanks again

[Marc Stock]

These heaters have a 20 min cut off btw. Its not like a proper heater. You have to cycle the heater

[nathankaye]

If you can rig up a pump i did try looking at the heating unit in a hit tub once, on a similar basis if circating the water.

[tomasxguty]

Already got just the right pump for the job. I ordered the unit today so will let you know  how well it performs once it arrived