Useful reading
Choosing a dry heating element for your tank: three measurements that matter more than the brand
Most people arrive with the same two facts: the brand on the tank and its capacity. "An 80-litre Atlantic", "a 50-litre Gorenje". That is a reasonable place to start, but it does not pick the element. A dry heating element sits inside a steel sleeve welded into the tank, and the sleeve dictates what fits. One manufacturer may have used several sleeve sizes across production years, so the badge on the casing narrows things down only roughly. This guide covers what to measure on the old element, which wattages and lengths typically go into 30, 50, 80 and 100-litre tanks, and where the elements we make in Stebliv fit into that picture.
Why the tank brand does not answer the question
The construction is straightforward. A resistance coil is fired into a ceramic (steatite) block, the block slides into a tubular sleeve, and the sleeve is what the water touches. Heat has to cross the sleeve wall, so the block must sit snugly and run the full depth. Sleeve diameter and depth differ between series, and even within one series a change of supplier could shift them by a few millimetres.
Hence the workshop rule: measurements first, catalogue second. If the old element has crumbled and cannot be pulled out whole, measure the sleeve itself, its depth and internal diameter.
Four measurements to take from the old element
- Seating length, from the mounting plate to the tip of the ceramic. This is the decisive figure. A longer element will not go in; a noticeably shorter one will fit but heat only part of the sleeve, so that section runs hot while the rest idles.
- Block diameter at its widest point. The air gap between block and sleeve is a poor conductor, and every extra millimetre raises coil temperature and shortens its life.
- Mounting type: a plate with two screw holes, a clip or a clamping nut. Note the hole spacing as well.
- Terminals: how many and of which type. A single element has two, either flat blade connectors or threaded studs. Our 600 W dry element, for instance, has M5 threaded terminals; if the old one used blade connectors, the wire ends will need new lugs.
Count the elements, too. Many 80 and 100-litre tanks carry two dry elements in two sleeves. Usually only one fails, but both have the same hours on them, so replacing the pair is the sensible option and replacing one is acceptable.
Typical wattage and length for 30, 50, 80 and 100 litres
There is no fixed rule tying litres to watts. The tank maker chooses power for a target heat-up time and for the wiring the appliance is meant to run on. Still, the market pattern is fairly stable and gives a starting point when the old element is not to hand. The table shows what is commonly found and which of our elements lands in that slot by power and length.
| Tank volume | Typical power | Typical element length | Our dry element in that slot |
|---|---|---|---|
| 30 L | 600–1000 W | short, roughly 300–330 mm | 800 W, L=325 mm or 600 W |
| 50 L | 1000–1500 W | around 400 mm | 1200 W, L=400 mm or 1000 W, L=400 mm |
| 80 L | 1200–2000 W, often two elements | 400–470 mm | 1500 W, L=470 mm or a pair of 1000–1200 W |
| 100 L | 1500–2000 W, usually two elements | 470 mm and up | 1500 W, L=470 mm; in a twin-sleeve tank, two of 1200 W |
Treat the table as orientation, never as permission to skip measuring. If the old element is stamped 1200 W with a 400 mm seating length, buy exactly that, regardless of what "usually" goes into an 80-litre tank.
Going up or down in power
Down is almost always fine if the element fits physically. The tank simply takes longer: 80 litres from 20 to 60 °C needs about 13.4 MJ, which a 1500 W element delivers in roughly two and a half hours and a 1200 W element in a little over three. For overnight heating that difference hardly registers.
Up calls for care. The thermostat and relay are rated for a certain current, and so are the cable and the breaker in the consumer unit. There is also a point specific to dry elements: a denser coil in the same ceramic length runs hotter, and the sleeve can only carry away so much heat. One step up, say 1000 to 1200 W, normally passes without trouble; doubling the power is an engineering change rather than a consumable swap.
Slimline tanks and immersion-type elements
Flat, slimline heaters split the water into two narrow vessels. Their sleeves are shorter, there are usually two of them, and the diameter can be smaller than in a round tank. Two spare centimetres of length and the element hits the bottom, so measuring the old part is compulsory here rather than advisable.
Older tanks use a wet, immersion-type element that sits directly in the water on a thread or a flange. The selection logic there is different: thread size or flange diameter, immersion length and the pocket for the thermostat probe. On material, copper sheds heat faster and is easier to descale, stainless steel copes better with aggressive water. We make both in 700, 1300 and 2000 W, for example the 1300 W copper element and its stainless steel counterpart. The 700 + 1300 W pairing is deliberate: many tanks mount two immersion elements of exactly these ratings on one flange for 2 kW total, with a mode switch running them singly or together. If one of the pair fails, replace it with the same rating or the modes on the panel stop meaning what they say.
Every item in our boiler heating elements category lists power and seating length in its name, the same two figures you took off the old part. Dry elements start from 256 UAH for the 600 W and go up to 305 UAH for the 1500 W at L=470 mm. If the diameter or the mounting leaves you in doubt, send us the measurements or a photo of the old element next to a ruler and we will check it against the drawing before you pay. These elements are made on our own floor in Stebliv, so the person checking is the one who builds them.
Frequently asked questions
Which dry element for an 80-litre tank?
Take the seating length and diameter off the old one. A single element around 470 mm points to our 1500 W, L=470 mm. Two elements at 400 mm point to a pair of 1200 or 1000 W. The brand on the tank comes second.
How many watts for a 50-litre tank?
Most often 1000–1500 W at about 400 mm. From our list, the 1200 W or the 1000 W, both at L=400 mm.
Does anything change for 30 or 100 litres?
A 30-litre tank normally has one short element of 600–1000 W; ours is the 800 W at L=325 mm. A 100-litre tank has one long 1500 W element or two of 1200 W. The principle is the same: sleeve depth rules.
Dry or wet element, which is better?
A dry element never touches water, so scale does not build on the coil and replacement needs no draining. A wet element is cheaper and easier to match by thread. You do not get to choose, though: the tank design fixes the type, and swapping one for the other without changing the flange is not possible.
Is there a universal element for Atlantic, Ariston, Gorenje or Tesy?
No. Each brand used different sleeves over the years. Match the three dimensions of the old element, length, diameter and mounting, plus the terminal type, and the badge stops mattering.