Temperature controller not working as you expect?

Temperature controller not working as you expect?



Temperature controllers, even the most modern ones, are generally not difficult to use. Functionality and accessible menus are the first condition for their suitability. The second is accurate temperature control. However, today we will focus on the problems we may encounter when implementing and subsequently using these devices. Why doesn’t the temperature controller work?

It sometimes happens that temperature controllers stop working or, if we are only at the installation stage, do not start working. To save time and nerves, it is worth looking at the reasons that may have interfered with their operation before starting the complaints procedure. Some problems require service repair, but most of us can deal with ourselves.


If the controller had been working properly for some time and suddenly stopped, the first thing to do is to replace the batteries and see if the problem persists. It can happen that, although there is no indication that they need to be replaced, the power supply weakens and the device starts playing tricks on the user.

With ENGO Controls temperature controllers, a set of batteries lasts on average for about two heating seasons. However, if any faults are noticed beforehand; unscheduled start-ups of the heat source, or inaccuracy of the schedule, start with the batteries.

REMEMBER: Before sending the regulator for service, make sure it has working batteries. Partially depleted batteries can weaken the signal.

Incorrect connection

Such a problem can arise when installing hard-wired controllers.

It is always advisable to follow the recommendations given in the connection diagrams. It is not only about the correct routing of the wires but also about their selection. Using unsuitable wires will prevent the use of all functions of the device.

When connecting ENGO Controls room controllers, it is recommended to use a 3 x 0.75 or 3 x 1 mm² cable. Then you will use all the functions of the controllers.

It is also worth remembering that the cable insulation should be suitable for 230 V installations.

Importantly, “twisted pair” internet cable, despite the required number of conductors, is not a good choice for a 230 V system due to the conductor cross-section and insulation class.

The temperature controller does not work due to a lack of communication with the receiver

The problem can happen when installing older type wireless controllers.

If the transmitter does not communicate with the receiver, ensure that the communication code of the transmitter and the receiver is set correctly. If the receiver controls the boiler inconsistently with the transmitter, you will need to change the communication code to something other than the factory setting. It may also happen that another wireless device is operating on the same frequency or our boiler is controlled by e.g. a neighbor’s controller. After changing the code, it is necessary to reset the transmitter and switch the receiver on and off.

To avoid this mistake, it is worth getting newer controllers. For example, the bestselling controller for boilers and other heat sources by ENGO Controls – E901RF – does not assume the manual setting of codes. It contains as many as 64,000 combinations, thanks to which a situation in which our controller is “controlled” by an unauthorized device is practically impossible. And even if – due to exceptional bad luck – such a situation were to happen, it would be enough to pair the transmitter and receiver again (for your convenience, they are initially paired at the factory).

Temperature controller does not work because devices have lost communication with each other

This problem can occur with a system operating wirelessly in a home network. Sometimes the temperature controller has stopped heating the room properly because it has lost communication with the control strip or the TRV head. In that case, it is worth carrying out a re-pairing of the devices or even a reinstallation of your control automation. It is well known today that a reset allows electronics to catch a ‘new breath’.

When the E901RF loses connectivity, we also re-pair the controller.

The controller turns the boiler on instead of off and vice versa

ENGO Controls are equipped with COM/NO (normally open) contacts for connecting a boiler that turns the heating on by short-circuiting the control contacts. However, if the automation of our boiler activates the heating by opening them, a controller with COM/NC (normally closed) contacts will be required.

On the E901 and E901RF controllers, you can change the relay type by software and everything will work as it should. To avoid complications, therefore, look for controllers that are as universal as possible.

Wrong location of the controller

We often don’t pay attention to where we install the control unit. We are guided by interior design, decorations, or, even worse, by chance. Meanwhile, the room regulator should be installed in the right place – non-sunny, far from draughts, fans, radiators, fireplaces, cookers, or even lamps. It is a good idea to hang/position it at a height of about 150 cm.

This is important because a bad location can cause the temperature sensor built into the unit to falsify its reading, causing the room to be underheated. If the temperature on the controller is falsely high, the boiler will not switch on and the room will be cooled. When choosing a location for the controller, it is therefore worth considering more than just convenience. Avoid locations that expose the controller to large thermal fluctuations. If this is forgotten, likely, that the temperature controller is not working properly.

In the case of wireless controllers, uninterrupted communication between the transmitter and receiver is also extremely important. Consideration must be given not only to the distance between the devices but also to possible architectural obstacles (e.g. thick walls) which may cause the signal not to reach the receiver.

Mistakes when setting the schedule or selecting a control algorithm

Although programming the schedule should not be complicated, mistakes can be made. If our temperature controller does not work flawlessly, i.e. it does not send out the heating demand even though we expect it should, the reason could be, for example, that we set the night-time temperature cutback at the wrong time interval.

The problem could also be the selection of the wrong control algorithm for our type of heating system, e.g. hysteresis for underfloor heating. The operation of hysteresis is based on slight overdrives, so it does not guarantee precision. Underfloor heating, on the other hand, has a long response time and high thermal inertia, so the heating effect may not be satisfactory.

Before we consider that the controller starts up at the wrong time or does not start up at the indicated times or parameters, a check will be made of the temperature ranges we have entered for each time of day.

We will also adjust the control algorithm to our type of installation. ENGO Controls mostly offer two control algorithms to choose from – hysteresis and TPI. By selecting hysteresis, you can specify the hysteresis range. By choosing the TPI algorithm, you can indicate for which type of heating it is to be used (underfloor, radiator, or electric). Devices designed strictly for underfloor heating operate on the basis of the TPI algorithm. This function takes into account the inertia of the underfloor heating, so that it closes/opens the actuators accordingly earlier/ later, preventing the room from overheating or cooling down.

The temperature controller not working properly due to incorrect control

Finally, remember that we should always adjust the parameters of the room controllers to suit our lifestyle. To do this, read the operating instructions carefully, and ask the installer or the manufacturer of the control automation you have purchased. Often, for fear of misprogramming the controller, we stay with the universal factory settings. Such reassurance is a mistake, as a mismatched controller will not meet our expectations, for which we will blame the technology. We must not be afraid to search for the settings that are perfect for us.


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