Reptile & Amphibian Forums

I was wondering why a few companies sell the dual on/off (Ranco) thermostats but not the dual proportional thermostats. Do the on/off thermostats malfunction that often/easily?

Or better yet...can I feel safe running a single Ranco unit on a 10-shelf snake rack? Or should I be paranoid the entire time?

(Just a note: The Big Apple Herp Power Proportional Thermostat has been a "set it and forget it" best friend. I have never worried. Well...okay...I was away on vacation for a week once and was starting to get worried during the last few days. I came home and it was right on the money. I haven't worried since. But I would like a digital readout.)

Thanks Again,
Chris
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mean people suck

I just read that the Johnson Thermostat has a safety feature that will cause the unit to shut off if it senses a problem. If this is correct, I may pass on the Ranco (dual and single) and choose the Johnson.

Any thoughts?

Chris
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mean people suck

...........all the mentioned stats.btw i have 3 BA herp power and two of them drift,2-3 degrees up or down.this year i'm using a herpstat on my incubator and it is flawless.have fun!

It's interesting that you say you have two Herp Power Thermostats that drift because I currently have 16 Herp Power Thermostats and none of them drift at all. I have tried 3 brands of Proportional Thermostats and I personally think the Herp Power blows everything away. It might also be interesting to note even my 5 year old Herp Powers still remain functioning perfectly.

Winston

Because you can't.

The ON/OFF units you speak of use mechanical relays and are actually cutting off power at the set temp limit. You can have a second ON/OFF unit in series with a higher setpoint as a backup as Boaphile sells prewired.

Proportional controllers use solid-state relays and maintain the temp by pulsing the heater at whatever rate is necessary to maintain the setpoint. You can't have two proportionals in series. But you CAN have an ON/OFF in series with the load set to a higher setpoint as a safety.

Two units in series are always more safe than one, even if the one has safety features. Why? Because the chance of both units failing at the same time is far lower than the chance of one unit failing at any time.

Thanks for the info. I was starting to worry about the Rancos. I saw them offered as dual units which made me think that a single unit is unreliable by itself.

Chris
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mean people suck

for over a year now and so far no problems. I was paranoid, and not knowing much about electrical stuff went with the double from Boaphile. Seeing how well they work now, I think I would consider using a single.

That cheesy little inexpensive Big Apple t-stat that some people like (mine was awful) has a built in cut-off ( I tested it and it appeared to work)Mine would run WAY too hot,then drift way down below the set and then WAY too hot and so on.

I wonder why some of the more expensive/proffessional units can't have a built in safety cut off that is dependable.
If we can put a probe on Mars and finally wheels on luggage you'd think it would be addressed by now if possible.

Bob

Hi Bob
Actually, there are industrial controllers (very small units too) that do what you say. Problem is, the controllers cost about $190 , then you must buy the solid-state relay with is $35, plus heatsink for the relay for $18, then wire it, then get the thermocouple probe for $20. This type of system will do 1000Watts easily, but costs more than most herpers want to spend I would bet.

If interested, do a search on Google for Omega Engineering, then go to their controllers section. I actually have one of these units from years ago. Real nice if you have some electrical background to wire it up. Real bad if you don't.

Hi Mark,

Thanks for the info. I'm in the "dark" about electrical knowledge. I understood evry other word you said. I'm downsizing right now and selling all my Neodesha cages so I won't be going for any more T-stats for the forseeable future.I appreciate your time.

Bob.

Both the Johnsons and the rancos will shut down if they sense a problem. My personal favorite is the JC units as they have the LED to let you know if the power is on or off and have a smaller foot print. The Dual setups are just the ultimate in safety. They DONT fail, but of the one in a million chance one will then your covered.. All of the herpstats have this feature they are more "advanced" so thats pretty much why they cost more.
Link

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www.MGReptiles.com
Professional Heating Supplies

Any idea of what exactly these units are sensing? Or how these safety features specifically work?

Chris
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mean people suck

If the unit is set for say 90 and the temp keeps climbing then it will shut itself off if the unit sees it cannot regulate itself. Also if the probe is damaged or if the probe wires are severed it will shutoff as it will not be ableto take its readings
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www.MGReptiles.com
Professional Heating Supplies

So let me get this straight...

The Ranco/Johnson/Herpstat unit is supposed to shut itself off when the actual temperature exceeds the set temperature. Isn't the excessive temperature problem normally created by the unit's inability to shut itself off? If so, how would the unit be ABLE to shut itself off when it is UNABLE to shut itself off?

Man! I need to stop trying to figure this stuff out! It's way too confusing! LOL

Chris
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mean people suck

I know Chris! LOL. That's why I just went out and bought the Double Ranco LOL. Good Luck!

Bob,

I just replied to your e-mail and it bounced back. It bounced the last time I e-mailed as well.

I'll try again later or post here.

Thanks Chris. I don't know whats up.

Duals are an awsome setup.. The chance of failue there is pretty much zero...
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www.MGReptiles.com
Professional Heating Supplies

Yeah, thanks. I hope so....

Do unintentionally fried snakes taste like chicken?