Double Thermostat - peace of mind!

[BOAS_N_PYTHONS]

EVERYONE:

I think this is the right section in the forums to chat about cage equipment and tools. So here goes. :)

Well these guys just came in today. Myself and Tim Cranwill have been researching a more durable, peace of mind, solid state thermostat unit for our collections for racks and cages. We asked around through emails, forums and friends about all types out there willing and able to handle large loads and multiple caging systems. As of now these units will be used for rack systems. You may have noticed a few posts from Tim on a great looking rack system he is building and almost completed. I myself still need to put the cut pieces together and set up this thermostat. After much research I settled on this unit and Tim joined my order to try this unit out as well.

All the pros / cons I researched on this unit and others made me think this unit will best fit my needs. I will test it out soon for about 2 - 3 months and if totally happy I will order a dozen more.

If you want to join that order, email me direct.

nemesisboaspythons@hotmail.com

The biggest plus being a double proportional thermostat unit, this means double protection against failure.

http://www.ssnakess.com/photopost/data/500/2330double_thermostat_000-med.jpg

I used much cheaper and simplier units for years but see I will be doing a clearance sale on those soon, :) .

Cya...

Tony

[Cruciform]

Got links to the site that sells those systems Tony?

Much appreciated :)

[Tim and Julie B]

Wow that is impressive.


Maybe now Tony can leave the house! :D


............maybe not.......


TB

[latazyo]

they sell those on boaphile for 200 bucks US, did you find them for a better price somewhere?

[MouseKilla]

Does proportional mean that it doesn't turn the heat source on and off to regulate it but instead give more or less power as necessary?

Would one of those work well for controlling the temps in a heated room connected to a baseboard or space heater?

[Stockwell]

Having dual controllers with triac type outputs doesn't necessarily give extra protection. With solid state outputs in series, if one shorts or opens, you're still screwed whether you have one or two... Actually with 2 of them, you have twice the electronic components to fail.
Double thermostats in series only really provide extra insurance when they are mechanical types with no electronic devices to fail, and even then mechanical snap switches and bimetals can also fail when they get old, although its less likely.
I think overkill is false economy.
I use dual systems in my hibernation room, but they are complete separate systems with two controllers and two heaters. I set one at 55F and if it can't keep up the second system pulls if temps fall to 52F...
This works well, but you know, I'm still screwed if the power fails, or if a power glitch blows both controllers. Ideally back up systems should use different technology and different components so that a specific factor that causes a functional fatality doesn't take out two identical systems at once.

[Stockwell]

Killa, proportional control is essentially what you stated.
It's actually what we call "phase control" in the electronics industy. A solid state output device called a "triac" is switched on and off at a variable rate during each cycle of AC line.
You can look at this as being simply a light dimmer that turns the heat up and down automatcially based on feedback from a temperature sensor.
With most units, such as the Helix there are various steps that the output ramps through as it switches the load current up and down to achieve "setpoint" So the the amount of current to the heater is "PROPORTIONAL" to how close the sensor temperature in the controlled environment is from the setpoint.
So the output is rarely fully on or fully off once it's maintaining the set temp. This type of control is suitable for resistive heaters such as heat tape, hot rocks or even light bulbs but not for anything with a fan in it. The chopped or "phased" waveforms from proportional controllers will cause fans to stall overheat and make noise.

Such control isn't as effective when heating entire rooms as supplemental High output modules would be required for baseboards. It's doable but the higher load currents of baseboards would require huge Triacs and big heat sinks making it impracticle. Proportional control ouputs produce alot of heat and that becomes quite a design problem with large loads.(like 1500watt plus baseboards)
Simple On-Off controllers with a one or two degree differential(swing) are best for room control.

I use 35 dollar Hunter setback thermostats from Canadian tire to control both my principle snake room and hibernation room. The term "setback" simply refers to the fact you can program different temps for different times of the day and obviously they are for use in heating your home, but that "setback" capability is great for cycling herp rooms up and down during different times of the day... all automatically
They are battery powered and a breeze to program but can't switch 120volt line directly. They must switch 24 volt relays,and then the relay contacts are used to switch line to your heater. So you need a transformer and a control relay to switch on the heater, but that is quite easy to do.
I use simple 1000watt fan blown room heaters that are only about 30-40 bucks.(Can tire,Walmart etc.)
Heaters with fans distribute the hot air more effectively than radiant baseboards.