Re: Parallel controlers - how to connect
The problem is that the Honeywell controller doesn't have a neutral; rather, it is powered by being wired in series with the load. When the DewStop (which does have a neutral) turns on, it short-circuits the Honeywell controller, rendering it unpowered. (It would be the same as if you jumpered a wire across the leads of the Honeywell.)
You can't wire these controllers in series, either. There's just no way to make the Honeywell work with any other switch or controller.
I recommend finding a programmable timer that has a neutral; it should be compatible when wired in parallel with the DewStop. It probably won't have all the features the Honeywell has, though.
The "Senior Member" designation under my name doesn't mean I know a lot, it just means I talk a lot.I've been a DIYer since I was 12 (thanks, Dad!). I have read several books on various home improvement topics. I do not have any current code books I can refer to. I was an apprentice plumber for two years.