[ChumBucket]

My 500ltr tank takes about 5 hours to get very warm with 3Kw. Might be worth bearing that in mind.

Is it a lay flat tank? The 3kw in my upright only heats the 2/3 above it and is only warm when I've driven around and the cold mixes

It is more cubed shaped, neither flat nor upright.

[AuRavelling79]

I've fitted three of these (3KW) and two of them I cut the holes "tight" with a hole cutter and screwed in the immersion (from toolstation) cutting it's own thread and mastic. This because I couldn't reach (or be bothered to make a tool to hold) the inside with a flange nut.

The present one has been in place and working for over four years.

I started with 13 amp plugs but like Dave's son said it's pushing it and terminals became hot and plastic scorched and so I got my bro. to fit 16 amp stuff like you have on a caravan.

I cut the hole with a hole saw - the type that has arms on it and infinitely adjustable.

Please note I have attempted four tanks. The first, third and fourth worked a dream. The second (a second hand 650) I seriously cocked up by cutting the hole fractionally big. I ended up cutting some plastic from a 25L drum and self tapping it and mastic'ing it in place but it was too thin to put the element back in and I didn't trust it. I ended up giving it to my son in law's father who is a builder and who needed a water tank in a remote off grid location.

Just be careful out there! 

[Dave Willis]

Your tank wall will be about 1/4" thick Dave if it's a Wydale.
This is what I use- http://www.toolstation.com/shop/p38614?searchstr=mechanical%20flange

It has a slightly longer thread and is easier to fit as there is no element attached to it. It also has three little lumps on the backnut which more often than not grip into the plastic tank wall meaning you can tighten the whole thing up without the need to hold the backnut with a spanner. These little lumps are there to create a space so that solder can flow between the two faces when it is being installed into a conventional copper tank. It also gives a much more robust and secure fitting. I have fitted Four like this and none have required any silicone/sealant at all, only PTFE paste on the threads just to be on the safe side.

That nut on the inside of the tank - where did you get that?

[Dave Willis]

I've fitted three of these (3KW) and two of them I cut the holes "tight" with a hole cutter and screwed in the immersion (from toolstation) cutting it's own thread and mastic. This because I couldn't reach (or be bothered to make a tool to hold) the inside with a flange nut.

The present one has been in place and working for over four years.

I started with 13 amp plugs but like Dave's son said it's pushing it and terminals became hot and plastic scorched and so I got my bro. to fit 16 amp stuff like you have on a caravan.

I cut the hole with a hole saw - the type that has arms on it and infinitely adjustable.

Please note I have attempted four tanks. The first, third and fourth worked a dream. The second (a second hand 650) I seriously cocked up by cutting the hole fractionally big. I ended up cutting some plastic from a 25L drum and self tapping it and mastic'ing it in place but it was too thin to put the element back in and I didn't trust it. I ended up giving it to my son in law's father who is a builder and who needed a water tank in a remote off grid location.

Just be careful out there!

To be honest Malc, that's the only way I can see to do it, not enough thread to get a backnut on even if I could reach it. I can see how the other method works well providing you can reach the other side ( I can't if I want it low). The tank is bolted in the van too so would be a lot of work to get it out.

[ChumBucket]

That's the other part of the mechanical flange- it's in Two parts, the inner (in question) has a male thread which is pushed through from the inside. The big nut (other part) is then screwed onto this from the outside and they clamp together. You are then left with a fixed flange in which you then screw your immersion element into. On the plus side to this you can also buy a blanking plate for the mechanical flange so that in the future should you wish to remove the element your tank isn't ruined.

[Dave Willis]

Cheers

[ChumBucket]

When you have the thing in your hand it becomes apparent what the crack is. You can afford a looser fit with this so it's a case of lowering the rear part into the tank and pulling it through the hole from the outside.

[Dave Willis]

Easy - loop of string should do it, start the nut let go one end anď pull the string out.

[ChumBucket]

Easy - loop of string should do it, start the nut let go one end anď pull the string out.

Bingo!

The Three little nodules on the back part- take a small file and flatten one side of each one, this will ensure it gets an initial grip and wont then require to be held from the inside.

[Jonny 87]

Nope, never saw it. Contacted the Bank and got my money back because I'd used a Visa Debit card.

Got two elements (one spare) this afternoon from Heatrod with flange nut. Took them two weeks because they had to be fabricated. 14" 2kw
Will fit one in the next couple of weeks - probably practice on a plastic bucket first!

That's a shame mate. When I got mine he must have been in the process of going under, poor communication but I got it in the end.

Glad you got your money back and blind Pierre's set up looks spot on. Finally makes sense.

You could do that, and insulate your tank with king span and you've saved yourself about £500 from Getting a custom built one.

I may do this for my static tank to be honest.