Tub Temps

[2.1SRR.YYC]

I'd like to know if anyone else is experiencing this...

I have a rack with 28 quart Rubbermaids, flexwatt and a Herpstat controller. When I adjust the temp on the Herpstat to give me 90 degrees on the surface of the paper towel, directly above the flexwatt, (measured with an IR thermometer) I have to bump the Herpstat up to 96 degrees. The probe is sitting between two tubs directly above the flexwatt. It's taped to the flexwatt at the base of the probe so the actual sensing part of the probe is about 1/8" above the flexwatt. There is no tape covering the sensing part of the probe. The rack temperature has settled over the last few days so the issue can't be due to a new activation.
The ambient temperature in the room is quite low, read 75 degrees.

Does this sound right? Should I be taking the paper towel out when I measure the temperature?

I would assume that the tub would act like a huge heat sink but would it set the temps off by 6 degrees? Do other people set their Herpstats higher than the desired temp in the tub?

 

[Grinning Geckos]

Yep, I do. You can counteract it by having a dummy tub, and placing the probe in there. However, that means you now have an empty tub on your rack.

 

[Leopardbreeder]

If you are measuring the temp at the end of the tape, and the herpstat on the beginning of the tape, the temps are different. Try measuring both sides of the tape.

 

[MichaelJ]

I would suggest using the dummy box method. We use a shoebox sterlite to save room. I tape the probe on top of the paper towel inside the box, to simulate the ways the leo's setups would be. My herpstat is set at 89 during the day and night drop at 79. When I use my IR gun on the tape itself its always way off, but does fluctuate from each lateral side. I hit the tape with the gun when the herp shows 88 and its said 110 at times. Yet I can touch my hands to it without any problems. I think the tape's make up of carbon strips, plastic, and space between heat strips, causes the IR gun to be off. Use the gun on top of the paper inside the tub to get accurate readings.

How old is your tape and herpstat setup? Did you run the tape without the stat for 24 hours to break it in? Then run it with the stat but no tubs for 24 hours also. It helps level itself off and get you a baseline.

Good luck! The first one I setup drove me nuttz! After that I built two more with my eyes closed.

 

[2.1SRR.YYC]

How old is your tape and herpstat setup? Did you run the tape without the stat for 24 hours to break it in? Then run it with the stat but no tubs for 24 hours also. It helps level itself off and get you a baseline.

Good luck! The first one I setup drove me nuttz! After that I built two more with my eyes closed.

The installation is about a week old.

I did not run the flexwatt without a thermostat to break it in. I didn't know this was something you should do. I thought I read that you should never run flexwatt without a dimmer or a thermostat. It's been running for almost a week now so I would assume it been broken in.

I don't want to waste a spot in the rack with a dummy tub so I think I'll just monitor the temps inside the tubs and adjust the Herpstat accordingly. It sounds like this is the way to go...

 

[2.1SRR.YYC]

If you are measuring the temp at the end of the tape, and the herpstat on the beginning of the tape, the temps are different. Try measuring both sides of the tape.

I just measured the temp on the flexwatt with no tubs on the shelf. At the hookup (left), middle and free end (right) of the flexwatt it was very consistent. It's about 36" across the rack. It always shows 99 - 100 degrees while the inside of the tub is about 90 and the Herpstat is set at 97.