DEL 13 / 18 / 27 Plus

The DEL Plus is a German-made instantaneous water heater designed for multiple outlets, supplying hot water to both single and group draw-off points — for example, bathroom and kitchen simultaneously. It is a sealed, unvented, pressure-tested appliance suitable for use with all commercially available pressure taps, requiring no safe tray, flue, or ventilation.

Electronically controlled with 3i Technology, the DEL Plus ensures precise temperature delivery up to 50°C. The rotary selector allows adjustment from 20°C to 50°C, with 0.5°C increments for showers. A backlit multifunction display shows the set temperature, current power consumption, status, and service indication. Features include an ECO mode for efficiency, memory keys for two programmable temperatures, and a pivoting cover with a programming unit for convenient under-sink installation.

By regulating output electronically, the DEL Plus saves energy and water, using only the power required to achieve the selected temperature — without the need to add cold water at the tap. Three sensors ensure accuracy, while the selectable ECO mode supports economical operation. The unit is also compatible with preheated water sources, such as solar thermal and heat pump systems.

The rapid bare-wire heating system is suitable for both hard and soft water. Safety is built in with an advanced electronic safety concept, including air bubble detection.

Contact your local energy provider with your address. They will confirm whether three-phase power is available at your property.

You will need an electrician to confirm the available supply in amps per phase. The DEL 13 Plus requires 20 A per phase, the DEL 18 Plus requires 27 A per phase, and the DEL 27 Plus requires 40 A per phase.

Check the amperage supply on the circuit breaker feeding your current hot water unit. Contact our team to confirm the most suitable STIEBEL ELTRON replacement model.

Underneath the temperature adjustment dial there is a flap that pulls forward and drops down. A rating label is located inside, showing the model and size (DEL 13 Plus, DEL 18 Plus, or DEL 27 Plus). A guide is also available in the downloads section of the DEL Plus product page.

Sizing depends on the number of outlets to be supplied and the incoming cold water temperature. As a guide:
• For a 1-bathroom apartment or house: a 19.4 kW unit (e.g. DHE 18 AU, DEL 18 Plus, DHB-E 18 LCD) is suitable.
• For a 2-bathroom house: a 28–29.1 kW unit (e.g. DHE 27 AU, DEL 27 Plus, DHB-E 27 LCD) is recommended.

The DEL Plus delivers hot water up to 50°C in accordance with AS3498. This eliminates the need for a separate temperature control device in hygienic areas where water must be limited to 50°C.

No. The DEL Plus is designed to deliver water not exceeding 50°C, in accordance with AS3498, removing the need for a tempering valve where water must be limited to 50°C.

The DEL Plus can be installed almost anywhere due to its compact size. It does not require ventilation, a relief drain, or a safe tray, so it can be installed in a cupboard, under a sink, in a service cavity, or in a Euro laundry. For outdoor installation, the unit must be protected from the weather (e.g. installed in a meter box).

The DEL Plus should be installed as close as possible to the most frequently used outlet to minimise water and energy waste. However, it is designed to serve multiple outlets several metres away from the system.