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Why get Web Server OZW672?

Do you have a heat pump but need to go down to the boiler room to change the temperature or check that everything is running? Or does your service technician charge for a visit to solve something that could be fixed remotely in five minutes?

Web Server OZW672 changes all of this. It is a small box that connects to your controller and your router – and suddenly you have the entire boiler room on your phone. And that is not all: your service team has access to full remote diagnostics, so they resolve most issues without a visit.

Don’t have a web server? The very first HOTJET heat pumps were not equipped with a web server – it did not exist at the time. In some installations the installer did not include one because it used to be optional. But nothing is lost. The OZW672 can be purchased and retrofitted to any HOTJET heat pump with Siemens controls. And not just heat pumps – the web server also works with gas boilers and other applications with compatible Siemens controls.

What you get

Control from anywhere

Set the temperature from the sofa, from work, or from your holiday. Switch to “holiday” mode when you leave. Turn on party mode when guests arrive. All you need is a phone or computer – it works from any internet-connected device.

Full boiler room overview, not just the heat pump

The OZW672 is not just “smart heat pump control”. You see everything the controller measures and manages: outdoor temperature, heating circuits, hot water, buffer tank, pool, solar, mixing valves, circulation pumps. Simple WiFi modules from competitors show you a few basic numbers. The OZW672 shows you the complete picture of what is happening in the boiler room.

Service without a visit

Saturday evening, minus fifteen, the heat pump reports an error. You call service, the technician connects within minutes, sees the problem, and often resolves it remotely. No waiting until Monday, no site visit. A few saved visits per year and the web server has paid for itself.

Automatic notifications

When something goes wrong, you receive an e-mail. No need to check the boiler room. No need to watch whether the heating is running. The cloud also checks the connection status every 5 minutes – if the internet or power goes down, it alerts you to that as well.

No monthly fees

Pay once, use for life. No subscription, no annual fees. Access for the whole family, the installer, service – everyone with their own permissions, all at the same time. After five years? Still free. After ten years? Still free.

Your data is safe

The cloud is operated by Siemens, servers are in Europe (primary in Northern Europe, backup in Western Europe). Encrypted HTTPS connection, full GDPR compliance. No dubious third-party services.

How it works – 4 simple steps

1. Plug in the cable

The OZW672 connects to your router with an Ethernet cable. Why Ethernet and not WiFi? Because boiler rooms, basements and garages are typical places where WiFi does not reach. A cable always works. If the router is not nearby, you can use a powerline adapter (Ethernet over the mains), an extender, or run the cable alongside PV cabling. Alternatively, install the OZW672 right next to the router and connect it to the controller in the boiler room via the two-wire bus.

2. The LED lights up

On typical home networks you do not need to configure anything – neither on the router nor on the web server. No IP address, no ports, no settings. Plug in the cable, the web server obtains an address from the router via DHCP and registers with the cloud.

3. Register on the portal

Create an account on the Siemens Synco IC cloud portal (free) and add your web server using the activation code. Registration takes a few minutes.

4. Download the app

The Siemens HomeControl IC app for iOS or Android. Log in with the same credentials as for the cloud – and you have the entire boiler room in your pocket.

What you see and control in the app

The HomeControl IC app is your daily window into the boiler room. A simple, clear interface:

• Current temperatures – outdoor, heating circuits, hot water, buffer tank, pool
• Temperature settings – for heating and hot water
• Operating modes – comfort, setback, holiday, party – with a single tap
• Time programmes – for each day of the week, for each circuit separately
• Fault alerts – via e-mail

And when you need more? From the app you can jump into the web interface with a single tap, where you can configure absolutely everything – hundreds of parameters, heating curves, diagnostics. It is more comfortable on a computer, but it works on a phone too.

Access for the whole family: Every family member, the installer, service – everyone can have their own account with their own permission level. The number of users is unlimited.

Remote service – real savings

Imagine this: it is Saturday evening, minus fifteen outside, and the heat pump reports an error.

Without a web server: You call service, describe what you see on the display. The technician guesses remotely. The earliest visit is Monday. They arrive, diagnose, perhaps need a part – another visit. Two visits, a few days in the cold, unnecessary costs.

With a web server: You call service. The technician connects within minutes, sees current temperatures, states, operating history. The problem is often resolved immediately – reset the fault, adjust a parameter, identify the cause. If a visit is still needed, they arrive with exactly what is required. One visit instead of two, hours instead of days.

Comparison: what you save

It is not just about money. You do not have to take time off work to be home when the technician arrives. You do not have to wait through the weekend for Monday’s service. You do not have to describe over the phone what is flashing on the display. You do not have to study manuals – we have done that for you.

For installers and service technicians

Why recommend OZW672 to customers

• Fewer warranty visits – remote diagnostics resolves around 90% of requests without a visit
• Happier customers – they have an overview, feel in control, call less with questions like “is this normal?”
• Professional image – you offer a service most competitors do not have, or do not know how to use
• Data in disputes – operating history, temperature records, operating states – everything is available

What the service technician sees – a completely different level

While the customer sees simple temperature and mode controls, the service technician has access to:

• Complete controller configuration – hundreds of parameters
• All sensors in real time
• Heating curves and their settings
• Diagnostics and operating history (last 500 events)
• Ability to change parameters remotely

Remote Tool Access via Siemens Synco IC

The Remote Tool Access function creates a secure tunnel to the web server through the cloud. You see and control everything just as if you were sitting right next to the unit. Compatible with the professional service software ACS790.

Typical use cases:

• Support during commissioning without being on site
• Remote comparison of parameter sets when troubleshooting
• Configuration adjustments after a phone consultation with the customer
• Creating a commissioning report from the office

Requirements: Web server firmware version 7.0+, access level “Service Level” or higher.

Limitations: Actions requiring physical button presses on the device cannot be performed. Continuous connection is limited to 24 hours (reconnection needed afterwards).

Trending and data logging

The OZW672 is a fully-fledged datalogger. 5 trending channels, each holding up to 100 data points. Sampling frequency is configurable from 1 second to 24 hours.

Recording capacity

Channel 1 has 7x larger memory for long-term trends – at 15-minute intervals with 100 data points, you store over a year of data.

Export: Web browser, e-mail, FTP/FTPS/SFTP. Local recording works independently of the cloud – the history is stored directly on the device.

Plant Web Pages – custom visualisation

Custom visualisation pages with a house floor plan or heating system schematic. You can place up to 100 data points on each page – temperatures, states, controls. When a fault occurs you immediately see where the problem is.

For standard HOTJET controller applications, schematics can be exported directly from the professional software ACS790 and uploaded to the web server.

Energy Indicator – monitoring energy efficiency

A function based on the EN 15232 standard. The web server monitors selected data points and compares them against set limits:

• Green leaf – value is within the energy-efficient range
• Orange leaf – value has exceeded the limit, the system is running inefficiently

Regular reports are sent by e-mail – an overview of whether the heating is working optimally or energy is being wasted somewhere.

Notifications and alarms – details

• E-mail notifications to up to 4 recipients with configurable priority (urgent / all)
• Sending schedule – 3 times per day + holidays / special days
• System reports at regular intervals (1–255 days)
• Physical button on the OZW672 for immediate report to all recipients
• History of the last 500 events – faults, messages, parameter changes
• Automatic connection monitoring – the cloud checks online status (every 5 minutes by default). An alert is sent when the connection is lost.

Three access levels

The number of simultaneously logged-in users is not limited – data throughput is shared between them.

Important: The web server is fully managed by the customer or installer. HOTJET only has access when the customer or installer grants it. This ensures fundamental security and trust.

Why Ethernet and not WiFi – technical reasons

The OZW672 uses Ethernet exclusively. Boiler rooms, basements, garages – typical places where WiFi signal is unreliable. Ethernet always works.

Alternatives when the router is not nearby:

• Powerline adapter (Ethernet over the mains)
• WiFi extender with an Ethernet port on the other end
• Cable run alongside PV cabling
• OZW672 installed next to the router, connected to the controller via the two-wire LPB/BSB bus

On home networks: DHCP, no router configuration. Plug in the cable, the right LEDs light up, the web server registers with the cloud.

In commercial environments: Consult with the IT department – outgoing connections on port 443 (HTTPS) may need to be allowed.

Connection interfaces