Ok, like everybody I struggled for some time with temps in my Boa rooms and of course worried about the controls on the danged space-heaters going out and my animals freezing or burning up! Here's my answer, a control device that provides the power to the heaters:
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I build those myself from off-the-shelf components. They are very accurate and reliable and have many of the same features for temp-settings, nite-drop and so on that expensive high-tech units provide.
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The purpose of the box is to allow for accurate control of the ambient room temps and provide a fail-safe against overtemp conditions if and when the cheap temp controls on electric space heaters fail. The thermostat is a $20 home-store unit equipped with a battery backup to hold programming, and is nearly infinitely adjustable.. including nite-drop! Here's a look at the inside works..
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This particular model is set up to be portable and for one output. Depending upon the number of poles in the relay and how you configure the inputs and number of power-outs you could easily allow for running several heaters or for a more permanent installation. Tip: oversize the relay (in terms of AMP capacity), here a 40AMP relay is used. Typically a 120V space-heater draws 15 amps or less. This much reduces the operating temp of the device and the wear or oxidation of the contacts. That's what causes failures. The transformer supplies the 24V control voltage for the contactor and the thermostat.. The box, thermostat, wiring strip, 120v/24v transformer, contactor and the cords can be bought at any Electrical supply store and many home or building centers.
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The non-metallic box is a little pricey ($40-50.00) but is a breeze to cut and drill and of course will not corrode or be a shock-hazard.. The whole device seen there was about $110.00. It would cost less if you have the little stuff like tye-wraps, screws and so-on laying around. More than worth it for the way it controls the temps and the piece-of-mind.
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Plug your heater(s) into this unit and connect the unit to power. Set up your room with the space heaters set for the maximum temp allowed and this controller set at the exact temps you want, it works like a dream.
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It's not complicated and all the pieces come with wiring diagrams and instructions but if you have zero understanding of how electricity works or circuit capacities get help selecting the components.
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Hope this info helps somebody this winter!
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Gus/Rio Bravo Reptiles.