Reptile & Amphibian Forums

What size heat tape should I use for a 32 qt rack system? 3" 4" or 11" also how long should each piece be. Also does anyone know if Johnson Controls Thermostat-Pre Wired With Night Drop is a good thermostat to use? Thanks for any help.

JC Thermostat will work, but for flexwatt I would think you'd want a proportional thermostat for your 'main' thermostat. The JC works great as a backup, but if I'm not mistaken it's an on/off device, and doesn't meter the current to the heat tape. Take a look at a Sypyder Robotics Herpstat ND or a Helix for your main themostat. The Johnson would work, though, but espeially if I was using 11" tape, I'd want a proportinal thermostat.

Is this a 'purchased' rack, or a homebuilt? If you're building it, make sure nothing sit or slides directly on the flexwatt.

As far as your question.. and of the tapes will work. Look at some pictures of other racks for ideas on how to mount. I would think a strip under the width of the back of the tub would be fine.
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Astronomy Picture of the Day

That should be a Spyder Robotics Herpstat... horrible typo in that message, and a few grammar errors. Thats what happens when I try to do a few things at once!
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Astronomy Picture of the Day

Its a homemade rack that I purchased from someone else. How would you suggest I not have the tubs directly on the heat tape for belly heat? And which size of heat tape should i use? 3" 4" or 11" I was thinking the 4" should work fine for a 32 qt rack. Thanks for the help!

Even the 3" tape would work well, but 4" might create a nicer warm spot.

As far as keeping the tubs off the tape, this is a MUST. You won't want to wear or scratch the flexwatt. If the rack is made so the tubs slide on the shelf they sit on with no play, you might have a hard time with that. I have 2" wide x 1/4" thick wood rails under the sides and across the center of the shelves that my tubs sit on, so there's some space for the heat tape and no way the tub can touch or rub on it. If you're rack doesnt have room for something like that maybe someone else will have some ideas. I guess if you can disassemble the rack you could miter out a channel for some 3" or 4" tape in the shelf. Other than that, maybe someone else will have some suggestions.
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Astronomy Picture of the Day

Hmmmm this might be kind of difficult. What about some type of barrier between them....what about that silver aluminum tape that they sell with the heat tape......could i cover the heat tape with this stuff to keep it from wearing out? Thanks for the help.

why is keeping tubs off the tape a "must"?

we have used it that way for more than a decade and it works just fine. you do want to tape it down so it doesn't crease or hamper movement, but how is it a "must" that nothing contacts the heat tape?
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robyn@proexotics.com

Pro Exotics Reptiles

If you've done it that way, it should be ok then. I was just hesitant to recommend a method that I hadn't used or verified. But.. if you've used it like that for that length of time, he should be fine using it that was as well.
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Astronomy Picture of the Day

I have worried about rubbing through the flexwatt causing a short but so far have had no problems. My tubs lay directly on the flexwatt .........If the internal grid is exposed by rubbing the plastic from pulling the tubs in and out this could be a fire hazard. I have been keeping a close eye on this with no problems so far in 2 years of using this method.I would recommend inspecting the flexwatt surface often just to be safe.

JC has been the only thermostat I have used , And this is an on off style thermostat. A proportional controll is a better unit but the johnson controll has some nice features. You can set the Offset so you can maintain within 2 degrees. Also there is a safety feature you can set so if there is a temp probe failure it will shut off or run full on wichever you choose.There is a cooling mode or a heat mode.......The temp probes are replaceable . As far as I know the night drop feature requires a timer that is fairly expensive. You can also wire in a basic on of switch for the night drop but it would have to be tripped manually , it just keeps your settings, So basically when you close the circuit with the switch it changes the temp settings to your night temps. I have a homemade rack that I run 36 ft of 11in heat tape with no issues . The unit is rated at 1000 watts so a small radiant heater can be used if needed for room heat. Ive been happy with the two I have due to the features and price.Ther are a few supliers around that sell these very reasonably.......These are very popular with people that brew there own beer for kegerators. Long post but hope it helps!

Sorry 1500 watt capable.

I currently have 4 racks of snakes, all handmade. One is a 6-tub 41qt rack that has two separate pieces of flexwatt on each shelf(one ft of 11" for warm side and 2ft of 11" for cool side). All of the hotside flexwatt is parallel wired and all of the cool side is parallel wired, ending up with two plugs.

I use a Herpstat 2 on it and the rack works great. The heat tape is held down well with foil tape, although I do need to redo it soon and possibly redo some of the connections since some aren't very flat. The tubs haven't messed up the tape or the flexwatt in the year and a half I've used this rack, so I figure it's fine.

The 2nd rack is an 8-shelf that holds either 8-32qt sterilites or 16-15qt sterilites. It has 2ft of 3" running along the back and 2ft of 11" flex running the rest of the shelf for the cool side. I use a Helix to control the warm side and a dimmer(that is plugged into the Helix) to control the cool side. When you put the dimmer down about 3/4 of the way from the top, and plug it into the Helix, the temps stay put. It's pretty cool

The other two racks are my baby racks(12-6qt tubs each), and they have 2ft of 3" flex running along the back(belly heat). Everything is parallel wired and both are running off of a Johnson Controls thermostat. With the On/Off tstats, I feel it's best to put the probe inside an uninhabited tub so the tstat isn't cycling on and off constantly while the flex doesn't even have time to heat up. You can also wrap the probe in a few paper towels or tape it to a thin piece of foam, so it creates a buffer. On/off thermostats work just fine with flexwatt, but they do work better if the probe isn't directly on the flexwatt.

Hope that helps!
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-Becky Brown, RVT-
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