whole house fan timers

Discussion in 'General Electronics Chat' started by Dave Brown, Nov 12, 2008.

  1. Dave Brown

    Thread Starter New Member

    Nov 12, 2008
    I am attempting to install a replacement timer for my whole house fan. The old timer had a red, white, and black wire. The new timer has a red, black and blue wire. The house wiring has a single black wire, two white tied together and a red and black tied together. I thought I would simply hook black to black, red to red and black, and blue to white. When I turned the power back on everything was normal. I pressed the on button on the timer and.....darkness, blew the house circuit breaker. Any help would be appreciated.
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    You might be into an interesting situation. It should work that the timer simply connects the house hot line to the fan. The blue wire from the timer is probably ground. You don't have a ground in your house wiring - it would be a green or bare copper wire.

    The two white wires should be AC common. They stay tied together. Your timer should not make any contact with the whites. The house black wire should be AC hot from the fuse or breaker panel. The red and black wires should be the lines switched out.

    Should be. If you cannot verify that these wires are as I have said, then you face a lethal shock hazard in dealing with them - and possibly a wiring fault that could cause your house to burn down. You will need a meter and some experience in doing so. If you lack the experience, then you really need to get an electrician out to see what is going on. Any exposed wiring could carry a lethal voltage.
  3. SgtWookie


    Jul 17, 2007
    Paying the tab for an Electrican's services is far less than that of a Mortician.

    Please trust me on this one.
  4. awright

    AAC Fanatic!

    Jul 5, 2006
    Simple matching of wire colors is not (as you have found) an adequate substitute for understanding the functioning of the original timer and the wiring embedded in your walls. Things can get a little complex depending upon whether the power source is brought into the timer box, with a loop up to the fan, or into the fan box, with a control loop down to the timer box. It can also be complicated if the person who did the original wiring followed the code or conventional practice.

    It may be possible, with considerable effort, for us to talk and analyze you through the situation, but it would require you to have a meter and possibly access the fan. It is probably much more practical for you to have an electrician actually trace where the wires go and how to wire up the new timer.

    Did you consider the possibility of using a thermostatic control, possibly in combination with a time clock?

    Good luck.

  5. mjd23

    New Member

    May 24, 2009
  6. Wendy


    Mar 24, 2008
    Have you looked at the dates on these posts? The OP (original poster) is long gone.