Question 1

How to set the manual mode of the Coati 12617 thermostat?

Accepted Answer

The Coati 12617 thermostat offers a manual mode to adjust the temperature independently of your usual programming. You can set it in two ways: temporarily until the next program, or permanently until you manually cancel it.

Temporary mode: Press the + or - buttons until the screen displays the desired temperature (between 5°C and 35°C). A symbol will flash on the screen to indicate that you are changing the target temperature. Then wait a few seconds without pressing any buttons: the temperature will be fixed and will alternate with the ambient temperature on the display. This setting will remain active until the next program is activated. To cancel this mode before this activation, press the SET button.

Permanently mode (HOLD function): Press and hold a + or - button until the word HOLD appears on the screen. Then select the desired temperature using the + or - buttons and confirm by pressing SET. The screen will alternate between your main screen and the target temperature accompanied by HOLD. This mode remains active indefinitely until you press SET again to deactivate it.

Useful reminders: Before using manual mode, make sure you have correctly set the control temperatures of your thermostat (comfort temperature around 21°C and economical temperature around 18°C by default). Manual mode only works for immediate temperature adjustment, not for modifying existing programs. If you wish to return to your usual programming after using temporary mode, the system will automatically switch to the next scheduled time slot.

Question 2

Why doesn't the boiler turn on with the Coati 12617 thermostat?

Accepted Answer

If your boiler does not turn on with the Coati 12617 thermostat, several checks are necessary to identify the cause of the problem. Here are the points to check in order:

Check the operation switch on the front of the thermostat. This manual switch directly controls the activation of the heating system. If it is in the 0 position, the boiler is completely blocked and will never turn on, even if the ambient temperature is well below the setpoint. Make sure to set it to position 1 to allow the thermostat to control the boiler according to the defined programs and settings.

Check the power supply to the thermostat. The Coati 12617 operates with two AA 1.5V alkaline batteries. When the battery level is low, a battery symbol appears on the screen. If this symbol appears, the batteries must be replaced immediately, as a weak battery prevents the thermostat from functioning properly. Also, ensure that the screen displays the time, date, and ambient temperature at startup: if the screen is blank or shows erratic information, press the RESET button using a pointed object.

Check that the thermostat is properly connected to the boiler. The Coati 12617 must be connected according to a specific wiring diagram: the L and N conductors must be connected to the boiler, and two specific cables indicated on your boiler's wiring diagram must connect the thermostat to it. A poor connection, a disconnected cable, or a reversed cable will completely prevent the boiler from triggering. Physically check the connections at the back of the thermostat and in the boiler.

Ensure that a heating program is active and correctly configured. The thermostat has 6 programming slots (P1 to P6) per day, over 7 days. If no heating program is activated for the current day and time, the boiler will never be triggered. Make sure you have configured at least one operating program (e.g., P1) and that it applies to the current day and time. The thermostat can only operate according to the defined programs or in manual mode.

Check the triggering temperature threshold. In economy mode (moon symbol), the boiler only turns on when the ambient temperature drops below 18°C minus an adjustable differential between 0.2°C and 1°C. In comfort mode (sun symbol), you can set a custom setpoint temperature between 5°C and 35°C. Ensure that the current ambient temperature (displayed on the screen) is well below the configured setpoint temperature for the thermostat to trigger the boiler.

Check that the HOLD mode is not activated. If the word HOLD appears on the thermostat screen, it means that the temperature is locked at its current value and the thermostat will no longer respond to the programmed triggering thresholds. Press the SET button to deactivate this mode and return to normal operation.

If after these checks the boiler still does not turn on, the problem is either due to a poor electrical connection between the thermostat and the boiler, or a fault in the thermostat itself. In this case, refer to the installation manual of your heating system or contact a qualified installer to check the connections and the integrity of the thermostat.

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