Herpstat Thermostat Problems

[Libitina]

hey,
I'm having trouble keeping the heat in our rack even. We have the thermostat set to 92 right now and we have Accurite thermo-hygrometers set up in each tub. However, those are reading temps like 88, 97, 95, etc. The tubs are all set up similarly in the rack (there are 3 tubs). Is there a way to get all the tubs to read the same temp.
Also, the temp still varies from day to day. The temp in the house does does not change much (stays right around 73 or so) but the temps read on the thermometers is never the same....could the thermometers be messed up? I don't get how they could be reading hotter than the actual flexwatt is getting :/
It's really frustrating....we had better temp control with a rheostat!
Any suggestions would be great! Thanks guys!

[Nate]

Where is the probe?

[Chuck]

hey,
I'm having trouble keeping the heat in our rack even. We have the thermostat set to 92 right now and we have Accurite thermo-hygrometers set up in each tub. However, those are reading temps like 88, 97, 95, etc. The tubs are all set up similarly in the rack (there are 3 tubs). Is there a way to get all the tubs to read the same temp.
Also, the temp still varies from day to day. The temp in the house does does not change much (stays right around 73 or so) but the temps read on the thermometers is never the same....could the thermometers be messed up? I don't get how they could be reading hotter than the actual flexwatt is getting :/
It's really frustrating....we had better temp control with a rheostat!
Any suggestions would be great! Thanks guys!

First I think we need some more info like were do you have the probe how is the rack set up and which tub is the probe in. Have you tried sampleing the heat at diffrnet places on the flexwatt? Do you get drafts in the room and is the rack on the ground and what type of sub floor do you have? Where in the house is the rack near a window or an outside wall. You are getting something that is causing that thermostat to constantly adjust the temps. Maybe the snake is laying on the probe?

[starmom]

In addition to whre is the probe, have you considered getting an IR temp gun? I have found it to be a real asset with my racks.

Also, are your racks on the floor? This could account for some of the fluctuations you are having.

[Libitina]

The rack is a 5 space rack made of melamine. We have three tubs in it right now, the top 3. The substrate is newspaper.
The probe is on the middle tub, in the middle of the flexwatt; we tried putting it on the edge (because we thought we would damage the probe by putting it underneath the tub) but it was much worse on the edge because it was not nearly as hot as in the middle of the flexwatt strip, so the temps were even higher. So we moved the probe to the middle of the strip (it doesn't get damaged b/c the tub is elevated just enough). It is under the snakes hide, so it does get laid on, though. Maybe we will try moving the hide so it is not right on top of the probe.
The rack sits on the ground. The room doesn't get much draft, the window is always closed; however it is right below the vent. We will definitely get an IR temp gun, just haven't had the chance, would they have them at any local stores (hardware stores, etc?)
Hope this helps, thanks!

[spyderrobotics]

Racks will always have temp gradient. The further away from the ambient temp you are setting the rack temp the more of a gradient it will have. Racks have no insulation so they sway much more when it comes to temp control. There are two basic ideas with racks:

Put the probe in a tub that is in the middle of the rack (or one rack below middle) as far as verticle orientation is concerned and then put a digital thermometer in one of the top tubs to monitor. Here the tstat probe will see a more uniform temp. The racks above it will be warmer and the racks below it will be slightly cooler (heat rises). Adjust the temp to get the results you want.

or

Put the tstat probe in a tub at the top of the rack and put a digital thermometer in a tub in the bottom of the rack. Here you set the temp to a warmer temp that is still acceptable knowing that all your racks below will be cooler. The thermometer in the bottom will moniter to make sure those are getting enough heat. Some like this better as you are controlling at the hotter temp so if the lower racks are cooler less problems animal wise.

Either way the two keys are ambient room temp and probe placement. I have never had great results with putting the tstat probe directly on the heating device. It always works best for me to have the probe actually in the tub and just tape it to the back wall of the tub. If the rack is next to a vent you will get swings. Same thing goes for racks that are on outside walls that get cold at night. I do not recommend IR thermometers. I find they will give confusing results. Digital thermometers with probes measure the temp the same way as the tstat so it will mimic the tstat more. Even the probed thermometers can be off by a couple of degrees but they will still show the temperature swings more closely. Plus they are a lot cheaper.

Hope some of that helps you!

Dion Brewington
Owner, Spyder Robotics

[Somed00d]

are the temperatures going up and down in each tub or are all 3 steady but different?

as for thermometers reading hotter than the flex-watt, that could be a heat build up issue. The flex-watt may be 92 at your probe but trapped heat can make your tubs hotter.

How is your heat tape wired? With 3 tubs it is not likely a wiring issue but I have had troubles keeping temperatures steady and the culprit was too much extension cord.