Every shower stays hot.
Without a single fuse tripping.
The EisBär DLE Controller actively regulates the power draw of decentralised electric instantaneous water heaters via flow rate and temperature — as load control and pooled control for up to 60 devices, cascadable beyond that. Both apartment and building connections stay within their protected capacity.
Load management in an MFH — example building, 4 units
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Live simulation: four apartments, one instantaneous water heater each, on a 69 kW building connection. The DLE Controller sheds EV charging, backs off the heat pump and reduces each unit's flow rate — the selected outlet temperature is preserved. Switchable to uncontrolled operation, where the fuse trips.
Less connected capacity, without a comfort trade-off
From an apartment building with six units to a property with sixty — one system that grows with you.
100% local
With EisBär's LNOT™ (Local Network of Things), the controller runs directly on site — stable and without cloud dependency.
Active pooled control
At any moment only a fraction of all units run at full load — in everyday use, not noticeable to occupants.
Cascades up to 60 units
Base unit with 6 water heaters, expandable in steps of 6 up to 60 — beyond that, a software licensing model scales further.
Lower connection costs
Reduced concurrent power lowers connected capacity, grid connection costs and the operator's connection charge (BKZ).
Everything for decentralised water heating
Protection, grid-operator connectivity, redundancy and integration — brought together in one system.
Power limiting via flow & temperature
The controller regulates each unit's maximum power draw via flow rate and temperature — continuously tracked, so neither the apartment nor the building connection is ever overloaded.
Automatic apartment protection
If a unit's total water-heater load exceeds its apartment's fuse rating, the system automatically adds a direct-metering apartment meter (Modbus) to protect that fuse.
§14a EnWG & grid-operator link
Software extension to limit grid draw per §14a EnWG, optionally connected to the grid operator via IEC 60870-5-101/-104, including a bidder acceptance test.
Fail-safe & redundant
A redundant setup with two controllers is possible. Remote maintenance is pre-installed for commissioning and ongoing operation.
Installation strings & gateways
One Modbus TCP-RTU gateway connects up to 30 Modbus devices (water heaters and meters) — as many installation strings as needed can be added for larger installations.
Remote maintenance & per-device commissioning
Commissioning and programming per water heater over Modbus, ready-to-run pre-configuration in-house; remote support bookable by phone or remote commissioning.
Static or doubly dynamic
Released power is distributed across the water heaters — either as a fixed value or continuously tracked from the building connection and PV.
Static
A fixed, defined current value at the supply point is distributed across all active water heaters.
- Released power fixed to the supply point
- Simple, predictable design without extra metering
- Suited to installations with a clearly defined grid connection capacity
Doubly dynamic
Available power is continuously tracked via measurement of the building connection and/or the PV system.
- Continuously tracked via power measurement in the building and/or PV
- Optional integration of PV systems and battery storage
- Maximum use of the capacity actually available
The diversity factor decides the connected capacity
Not every unit runs at once — the diversity factor ϕ < 1 describes the share of installed power actually drawn simultaneously in the worst realistic case.
P_glz = ϕ · P_inst — as the device count N grows, ϕ falls, because the odds of every device running at exactly the same moment shrink.
The EisBär pooled control applies an actively enforced rule instead of a statistical approximation:
P_glz = ⌈N · 0.10⌉ × P_unit— at most 10% of all units run at full load simultaneously, rounded up to whole units- From delivered projects: 20–30% reduction in simultaneous power versus uncontrolled operation
- Cluster logic: only similar consumers (same room type + same device power) are pooled together
BERECHNUNGEN.md
Two wiring variants
Line-wired Modbus infrastructure with or without per-apartment metering — depending on whether the apartment fuse needs its own protection.
Direct connection (line)
One gateway connects all water heaters via a line-wired Modbus bus; metering happens only at the building connection.
With apartment protection (metered)
One shared Modbus gateway serves several apartments — each gets its own Modbus meter behind its own distribution board, so the controller also protects each individual apartment fuse.
From an apartment building to an entire property
One base unit, expandable in steps of six — beyond that, via software licence.
- DLE Controller 6 — base unit licensed for 6 water heaters, DIN-rail mounting incl. power supply
- Software extension in steps of 6, up to 30 units
- Hardware/software extension for a further 30 units, up to 60 water heaters
- Beyond that: software licensing model (EisBär dongle, Architect/Enterprise) — scales further, mirroring the DLM Controller
- Redundant setup with two controllers possible
Everything from a single source
Sizing, commissioning, metering and remote maintenance — pre-configured in the DLE Controller.
Sizing & cost estimate
An internal EisBär sizing tool automatically computes several diversity-factor variants per project, compares them, and produces a cost estimate for controller, extensions and commissioning.
Download sizing toolTurnkey commissioning
Commissioning and programming per water heater over Modbus, ready-to-run pre-configuration of the controller in-house, without on-site assembly.
Remote maintenance & support
Commissioning support bookable by phone or remote maintenance, as well as full remote commissioning of the controller.
Grid analysis & warranty
Network-connected grid analysis meter incl. setup for building and §14a metering; optional warranty extension to 24 months with advance replacement.
Open protocols instead of a silo
Water heaters, meters and grid-operator interfaces — connected via standard protocols.
Wherever hot water is generated decentrally
From multi-storey residential buildings to combination with charging infrastructure — at every grid connection with limited capacity.
Terms around water-heater pooled control
The key terms, briefly explained.
DLE / E-DLH
Instantaneous water heater — heats drinking water decentrally, without a tank, right at the point of use. Typical power tiers: 3.7 / 11 / 24 / 27 kW.
Diversity factor ϕ
A dimensionless factor between 0 and 1: the share of installed power actually drawn simultaneously in the worst realistic case.
Cluster
Group of all rooms sharing the same room type and device power, across every floor and unit — the basis of every diversity calculation.
Installation string
A Modbus TCP-RTU gateway plus bus line, to which up to 30 Modbus devices (water heaters + meters) can be connected.
Apartment protection
An automatically added, direct-metering apartment meter, triggered once a unit's total water-heater load exceeds its fuse rating.
DIN 18015-1
Standard for electrical installations in residential buildings, Part 1: planning fundamentals. Figure 4, Curve 1 gives diversity values for electric water heating.
Frequently asked questions
Answers from tender documents, the sizing tool and project practice.
What's the difference between the DLE Controller and the DLM Controller?
The DLE Controller regulates electric instantaneous water heaters for decentralised water heating; the DLM Controller regulates EV charge points. Both run on the same EisBär platform (SCADA, LNOT™) and can be combined within the same overall concept — e.g. in an apartment building with showers and charge points.
Which water heaters is the controller designed for?
Primarily for CLAGE ISX units with a Modbus interface, whose integration is separately documented. In principle, the make and model of the connected water heaters is freely selectable via the built-in Modbus drivers and can be mixed within one system.
How many water heaters can be connected?
The DLE Controller 6 base unit is licensed for 6 devices, expandable in steps of 6 via software or hardware/software up to 60 devices. Beyond that, a software licensing model (EisBär dongle, Architect/Enterprise) applies — mirroring the DLM Controller.
How does the pooled control work technically?
The controller ensures that at most 10% of all installed devices run at full load at any one time (rounded up, so at least one device is always secured even with small device counts). Comparable, realised projects show a 20–30% reduction in simultaneous power versus uncontrolled operation.
Is control static or dynamic?
Both are possible: a static current value at the supply point, or doubly dynamic control with continuous tracking via power measurement in the building and/or the PV system. Battery storage can optionally be integrated too.
What is the diversity factor and what is it for?
Since not every water heater runs at once, the power actually drawn simultaneously is estimated via a diversity factor ϕ < 1 (P_glz = ϕ · P_inst). It is decisive for sizing the building connection, transformer and supply cable.
Which standard is the calculation based on?
The reference is DIN 18015-1, Figure 4, Curve 1 (with electric water heating for bathing or showering), evaluated by log-linear interpolation. Final sign-off of the connected capacity remains with the responsible grid operator during registration and commissioning.
Is there a tool for sizing and cost estimation?
Yes. The EisBär sizing tool models floors, rooms and device types as a project tree, automatically computes several diversity-factor variants per cluster with a side-by-side comparison, and produces a cost estimate for controller, extensions, commissioning and metering.
How is the apartment fuse protected?
If a unit's total water-heater load exceeds its configured fuse rating, the system automatically adds a direct-metering, Modbus-based apartment meter to protect that fuse — in addition to protecting the building connection.
What is an installation string?
One Modbus TCP-RTU gateway connects up to 30 Modbus devices — water heaters and meters combined. If an installation exceeds that count, a further installation string (gateway) is added automatically.
How is total power measured at the building connection?
Via a network-connected (LAN) grid analysis meter, including ready-to-run setup. Current inputs for transformer measurement up to 5 A are provided; current transformers, data and power wiring, and mounting are supplied on site.
Does the controller support §14a EnWG?
Yes, via a software extension that limits grid draw per §14a EnWG. The grid-operator connection can additionally run over IEC 60870-5-101 (2-wire) or IEC 60870-5-104 (LAN); a bidder acceptance test together with the grid operator is bookable as a service.
Can the controller be set up redundantly?
Yes, the system can be set up redundantly with two controllers; the base functionality is adapted to project-specific requirements.
How does commissioning work?
Commissioning and programming happen per water heater over Modbus, with ready-to-run pre-configuration of the controller in-house, without on-site assembly. Metering, data cabling, and mounting and wiring are supplied on site; internet access for remote maintenance is provided on site.
Is remote commissioning possible?
Yes, in addition to phone- or remote-maintenance-based commissioning support, full remote commissioning of the controller is bookable.
What hardware is inside the controller?
A controller with a pre-installed EisBär SCADA 3 Suite, two network ports (local device network plus a separate campus network), an external plug-in power supply, a Windows OS with a 128 GB SSD, and a DIN-rail mounting adapter. A Modbus RS485–LAN interface for DIN-rail mounting is included; a 24 V/DC power supply is required on site.
Is a warranty extension available?
Yes, optionally extended to 24 months with advance replacement.
Can the DLE Controller be combined with the DLM Controller (load management)?
Yes. As part of an overall concept for apartment buildings, several controllable water heaters can be integrated alongside EV charge points — both controllers share the same EisBär platform.
How much can pooled control actually save?
Experience from realised projects shows a 20–30% reduction in simultaneous power versus uncontrolled operation. The reduced connected capacity typically also lowers grid connection costs and the operator's connection charge (BKZ) — in practice, occupants don't notice any comfort trade-off.
Does the controller run 100% locally, without a cloud?
Yes, via EisBär's LNOT™ (Local Network of Things), the solution runs directly on site and guarantees maximum stability and secure local data exchange — without external cloud dependency.
Ready for your water heater installation?
We advise on sizing, diversity factors and connectivity — including a cost estimate from our sizing tool.
Get in touch
Imprint
Alexander Maier GmbH
Beckstraße 3
D-69412 Eberbach
Managing director: Alexander Maier
Registered office: Eberbach
Register court: Mannheim
Commercial register: HRB 335404
VAT ID: DE177682654
Phone: +49 (0) 6271 – 91 94 70
E-Mail: info@busbaer.de