HUMIDISTAT AND TIMER - Constantly running or Running when it shouldn't

If you have reached this article before checking your model isn't designed to run continuously please read that article first by clicking here - Why won't my ventilation fan turn off or why is it running when it shouldn't?

As you have a humidistat and timer model of fan, we need to confirm the settings and the wiring configuration. Fans that make use of a timer are factory set to over run for 15 minutes up to a maximum of 30 minutes. It is important that this period of time is allowed to elapse. We would suggest checking the timer is set correctly and would refer you to the individual product manual for instructions on how to do this. 

If after the timer setting has been exceeded your fan is continuing to run, the humidity setting will need to be checked and then confirm that the ambient humidity is not above the set point. Your fan has a humidistat which detects the humidity level in the room. All rooms have humidity in them and even though you might not be able to see it, the rooms ambient humidity might be above the setting. We would advise turning the humidistat up (clockwise) to reduce it's sensitivity. The humidity setting is factory set at 75% but further information can be found in your individual product manual.

If you are confident that the humidity level and setting are correct the next thing that needs to be looked at is the wiring connections to the fan. Humidistat and Timer models have the below wiring configuration, and for best performance of the features it should incorporate a "switched live" to the T terminal. This connection must go through a switch (often the lighting circuit) and cannot be supplied by a permanent live. The switched live is optional though and if choosing to connect your fan without it, this terminal must be left blank. If you choose not to include a switched live it will mean the fan will turn on and off solely based on the ambient humidity.

Wired without a switched live

If your fan is wired without a switched live and is continuing to run this would strongly indicate that the environment is above the humidity set point or a permanent live is connected to the T terminal. If your product is within the guarantee period, you have checked and confirmed all of the above please raise a ticket confirming:

1. you do not have a fan designed to run continuously

2. you allowed the timer to run for over 30 minutes 

3. there is 0V on the T terminal

If your product is out of the guarantee period then a replacement product would need to be purchased.

Wired with a switched live

If your fan is wired according to the diagram above, the switch is off and the fan is continuing to run passed the timer then it would suggest something less obvious is causing this. This is unlikely to be a fault with the fan though but rather a result of a small amount of voltage being detected on the T terminal causing the fan to run when it shouldn't.

All installations must be supervised by by a qualified electrician and we would recommend that they check for any voltage on the T terminal. Any voltage detected confirms this is not a product fault but rather an external factor which needs to be remedied first.

This phenomenon is a natural occurrence caused by an electromagnetic field inducing a voltage between parallel conductors within the cable cores. For more information on this we suggest this article - Induced Voltage

If your product is within the guarantee period, you have checked and confirmed all of the above please raise a ticket confirming:

1. you do not have a fan designed to run continuously

2. you allowed the timer to run for over 30 minutes 

3. there is 0V on the T terminal

If your product is out of the guarantee period then a replacement product would need to be purchased.

Applicable Models:

DX100BHPT, DX100BHT, DX100HTA, DX100HTAP

DX100BHTR, DX100BHTS, DX100HPTR, DX100HPTS, DX100HTR, DX100HTS, C4HTS, C4HTR, C4HTSR, LV100HTA, LV100HTAP, LV100BHPT, LV100BHT, LV100HTA, LV100HTAP, SSLV100HPTS, SSLV100HPTR, SSLV100HTR, SSLV100HTS, DX150HTS, DX150HTR, C6HTS, C6HTR, C6HTSR