Here are some
additional comments and tips from Ira Perlow who recently built
three of the circuits:
After building the timing circuit based upon the 4528 IC, here
is some additional info that you might want to add.
- Don't route wires anywhere where they may touch the heater
or the metal pipe going from the pump motor to the heater. These
get very hot and you don't want the insulation to burn. Make sure
that they can't fall onto these hot surfaces at a later time by
shaking or melting.
- Make sure you insulate (I use heat gun glue alot of the time)
the 120 volt transformer AC leads and the relay contacts on the
top and bottom of the circuit board and anywhere they would be
- The 4528 IC circuit cycle time is the length of the space
plus pulse width added together.
- I mounted my circuit board on the bottom inside of the fogger
as there was room, heat rises away from the board (and thus might
affect the circuit's reliability in a positive way), and it allowed
easy removal of the cover. I used standoffs for the circuit board,
as well as for the transformer. The transformer was mounted in
the front inside of the fogger next to (but a good 1/2" or more
away) the heater.
- Since my relay contacts were in parallel with the remote
cable switch, I can use the remote to give some extra fog if needed
to supplement the fog timer.
My fog timers (3 foggers) are working great and hopefully will
see a full-up test at my son's school's Haunted House this coming
Halloween season (and my home haunt on Haloween Night!) Regards,