Sounds like your '3 way valve' is stuck click here
central heating 3 way valve stuck
you can manually move the switch on it for a temporary solution, but first you will have to do your homework and identify the type that you have.
Sea of Thieves Review
Dell Canvas review: the cheap Wacom Cintiq alternative
How to use iMovie for Mac, tips and more
Comment filmer l’écran d’un iPhone ?