At Butler Technik we receive a lot of inquiries about the temperature reading displayed on the Webasto MultiControl timer. Often these inquiries relate to the difference in ambient air temperature and the temperature reading displayed on the timer.
Why is the temperature different?
Be aware that it is not unusual to see a few degrees difference between the temperature reading on the controller and the ambient temperature of the room or cabin.
To understand this difference, you need to know what the timer does to monitor the temperature from the moment it is set up. The following also applies to the Webasto SmartControl. This does not apply to Webasto water heaters.
When it is first set up the controller goes through an automatic check sequence and selects the first available temperature sensor. It is not possible to manually select the sensor.
The query sequence is as follows:
- External sensor on the W-bus
- Sensor in the heater
- External sensor connected to the UniBox
- Internal sensor of the MultiControl/SmartControl
If your heater configuration has only the internal heater sensor available, the temperature displayed on the timer is the temperature of the air entering the inlet at the heater. This can vary greatly to the ambient room temperature due to how and where your heater unit is located. It will be affected if you are drawing air from outside your vehicle or vessel.
How do you improve the temperature monitoring for the Webasto MultiControl timer?
To improve the ambient air temperature reading the following solutions are put forward.
- Recirculate the air within your vehicle or vessel. If you are not already recirculating the interior air, you will see an improvement by doing so.
- Install a remote temperature sensor. When connected to the heater the remote takes the place of the heater’s internal sensor. As this will be the first sensor discovered by the controller during set up the temperature reported on the controller will be that of the air around the remote sensor..
If you're adding a remote sensor to an existing installation you will need to reset the controller. You will find instructions on how to complete this task in the controller's installation manual.
You may also require the Webasto MultiControl wiring harness if you do not already have one.
See diagrams for Multicontrol wiring connectors to the Air Top 2000 STC, Evo 40 and EVO 50 heaters.
Where do you locate the remote sensor?
It is important to locate the remote sensor away from the warm air outlet of your heater. Hot air rises so placing it close to the ceiling will give incorrect readings, as will placing it too low. Mid-way up the wall and on the opposite side to the heater outlet/s is usually ideal.
If you need help please contact the Butler Technik support team. We are always happy to help.
