Heater Control Valve Requirement

Hey FABO,

I'm installing an aftermarket A/C & Heater combo in one of my projects. Do I absolutely need a heater control valve? I understand that if it's not there, the engine coolant will just flow through the heater at all times. But, without the heater blower running there won't be any hot air coming out of the vents. Is this an issue? Is it a problem for the heater core?

Thank you for any replies.