BUT where can I get a Single Pole, Double Throw switch with Center OFF position ??
Do you just mean one like THIS ?? http://www.modelrectifier.com/search/product-view.asp?ID=1251
I suppose I could get one from RadioShack ?
That switch should be fine (you only need single pole, but double pole will work just as well). You should also be able to get a similar switch from RadioShack. Whatever switch you choose; make sure that it meets the specifications for your fireplace. Assuming it uses a thermocouple, the voltage and current should be very low, but it is worth double-checking the requirements in the fireplace installation manual or with the manufacturer.
How would you wire it ?? i.e. can you do a diagram for me ?
I have drawn a diagram below using a SPDT Center Off switch (using a DPDT CO switch you would just ignore the second row of connections on the switch). In the up (or
On) position the fireplace will always be on regardless of the state of the UM506. In the middle (or
Off) position the fireplace will always be off regardless of the state of the UM506. In the bottom (or
Auto) position, the fireplace will be on when the UM506 is on and off when the UM506 is off. You would normally keep the switch in the
Auto position and only use the other positions in the case of a power failure. I haven't actually tried this yet myself, but I don't see any reason why it wouldn't work.
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