How do you change a relay switch on a nutone cv-450

SOURCE: Nutone CV 450

If the top comes off, it will be by the motor and exhaust. Just replace it with the new one, make sure you don't mix up any wires. Also unplug it from the AC first.

SOURCE: have a nutone CV-450. Suction is gone at the

The first thing to do is to disconnect the pipe coming into the unit. If there is suction there than you probably have a break in the line. If there is no suction when you disconnect the pipe coming into the unit than it is most likely the motor gasket. This gasket can sometimes get sucked into the motor causing problems. Remove the lid to the central vacuum, than disconnect the motor, you should be able to tell if maybe the gasket has been off center or if it has been sucked up in the motor.

SOURCE: A Nutone CV-450 System with inlet nozzle switch issues

You are suffering a connection problem of the hose end fitting to the wall outlet. Either the hose is not aligned with the two pins in the wall outlet, or the pins in the outlet are dirty and not making good connection to the hose end fittting.