Willis style external element

[TheTouringOne]

Hi All, just popped over from the sparky forum to get an opinion on something....

Need to heat a standalone plastic bath tub to normal bathing temp and maintain it indefinitely. Not a plumbed system, totally stand alone.

Considering using a Willis style external element and having the normal heat-syphon action create a constant loop, feed in and feed out via the tub and just rely on the built in temp sensor to hold it. BUT..... as I know these are normall used with GF systems, do we think this will work as it basically won't have any head pressure to start with. I guess I could also put a pump in it if really needed but want to keep it as simple as possible. It also has to be portable and travel so needs to be as lightweight as possible too.

Alternative suggestions are also welcome!

 

[ShaunCorbs]

Is there any time restriction eg heated within 30mins

 

[TheTouringOne]

Is there any time restriction eg heated within 30mins

Not really, an hour or so to bring up to temp would be fine

 

[ShaunCorbs]

That would be fine but use a bronze pump or stainless steel etc worst comes to worst you could have two in parallel if you found the heat up time too long would roughly 1/3 the heat up time

 

[Ben-gee]

What’s it for, what are you trying to do?

But more info and we can think around it a lot better.

 

[TheTouringOne]

As described up top mate, literally heat a bath tub of water that's not connected to any other system.

NB - The electrician in me has already discounted those horrible throw-in plug top element things that are an accident waiting to happen!!

 

[ShaunCorbs]

As described up top mate, literally heat a bath tub of water that's not connected to any other system.

NB - The electrician in me has already discounted those horrible throw-in plug top element things that are an accident waiting to happen!!

Can I ask why ?

 

[TheTouringOne]

Can I ask why ?

Why the project or why rejecting the plug-in heater immersible stick things? The project is to provide an instant ice bath / hot bath (not the same tubs, clearly) for dancers coming off a stage and the reason for rejecting the immersible elements is down to risk of damage/safety concerns.

 

[ShaunCorbs]

The plug in heater sry should have said

It’s the same as a cylinder immersion just a element in a tank

 

[TheTouringOne]

The plug in heater sry should have said

It’s the same as a cylinder immersion just a element in a tank

They take an age to work and most of them crap-out at around 35C. Also, most of the ones I've seen are basicall a bare element in a metal holed shroud that looks more like a lady's pleasure thing and in a plastic tub if it faulted it probably wouldn't trip an RCD until someone put their hand in it.

 

[ShaunCorbs]

Only other option is a 80l direct unvented cylinder