Infrared Ceiling Heating Installed, but the Flat Is Not Warm Enough. What Can I Do?

If infrared ceiling heating draws the required current but you still do not feel the expected warmth in the flat, first check the limit value of the thermostat's secondary sensor above the plasterboard. If it is set low, the heating switches off too early; after raising the limit, the heating film runs for longer and more heat reaches the living space.

What does a ceiling heating thermostat measure?

The thermostats we supply for our heating systems work with two sensors. One monitors the air temperature – this is mostly the value shown on the display. The secondary sensor is placed above the plasterboard ceiling, between the heating films. This is where you can set the maximum temperature allowed above the plasterboard. The limit protects the structure of the flat and the safety of the heating, so it must not be switched off – only set correctly.

Why does the flat not warm up?

The problem appears when this limit is lower than necessary – for example set to 40-45 degrees – or the thermostat has for some reason reverted to a much lower factory value. Then it does not help to ask for 23 degrees in the room: as soon as the sensor above the plasterboard reaches 30 or 35 degrees, the thermostat simply switches off the heating. So the system is not faulty, it is just not allowed to work enough.

The solution: a higher limit in the service menu

The limit of the secondary sensor has to be raised to a higher temperature. With a suspended ceiling this can in extreme cases be 50-55 degrees; in practice our colleagues usually hand over ceiling heating with a value between 45 and 55 degrees. For the thermostat in the video, the setting looks like this:

• Menu item 4 – which sensor counts: with "IN" only the sensor built into the thermostat (we do not use this), with "OU" only the external sensor, with "AL" both. In a flat we use both sensors.
• Menu item 9 – the limit of the external sensor: on the device shown it was 35 degrees; for ceiling heating this has to be raised to the range above.
• Saving: by switching the thermostat off, the change is kept.

Opening the service menu is shown in our article on calibration; with other types of thermostat the menu items may differ.

Related articles

With underfloor heating the symptom appears the other way round – the air is warm, the floor is cold – and different limit values apply: you can read about it here. Our topic page describes how ceiling heating works, and our article on ceiling heating goes into its advantages in detail.