I have a 2021 Skoda Octavia SL T I 1498CC petrol engine.

I can set the heater temperature which sometimes warms up other times it warms up then after a short time it starts to blow cold air.

I have done all the usual checks.

Does anyone have a similar problem.

Thanks in advance

How cold is cold?

Seems an odd question for me to ask but bear with me...

I usually leave my Clima settings on Auto. This will blow warm air to warm the cabin as required but then after a short time, when the cabin has warmed up) the air flow reduces and the air coming from the vents does feel cool. But not cold. Any air at ambient temperature flowing over our skin will feel cool because of moisture evaporation and I reckon is normal with the Clima on Auto which heats or cools the fresh external air as necessary to maintain the internal temperature.

Another thought, with several bodies in the car and/or driving in to strong sunlight the air inside the cabin will naturally warm up so the Clima system will likely move from a heating phase to a cooling phase to maintain the set temperature.

I don't use Clima on auto. This morning as way to rest I set it on Hi.

After a while this became overpowering so I turned it down to 25 and it started blowing out cool air. The temperature in the cabin certainly wasn't 25.