Getting some strange temp readings throughout my rack.

Here is my current setup:
6 tub (28q) PVC rack with 4" THG heat tape. Thermostat is a Vivarium VE-100, I also have a Thermoworks (TW) 2 probe digital thermometer and for double checking temps and humidity I have another digital thermometer in the rack. I use aspen bedding, and have two hide boxes per tub.

So the VE-100 is set to 93deg (probe for the VE-100 was reading 92 at the time I checked temps which is fine it can drop by 2 degrees before kicking back on).
I have taped the probe for the VE-100 and one of the probes for the TW right to the THG heat tape next to each other near the beginning of the heat tapes run through my rack. The probe for the TW was reading 95 at the time the VE-100 was reading 92 so that's a bit upsetting. Inside the rack the other TW probe and the backup temp probe were reading 86 and 87 degrees respectively.
Today I took my IR temp gun and pulled each tub out to spot check the hot spot and cool spot temps. Starting from the top tub, which I labeled #1 down to tub #6 here are the hot and cool side reading I got.
#1: 90/83
#2: 95/83
#3: 95/86
#4: 97/85
#5: 96/84
#6: 96/84

So my fear is that things are too hot, though several of the snakes seem just fine hanging out in their hot side hide boxes.

Is this something wrong with the heat tape or the VE-100?
Should I consider changing to 3" heat tape?
Should I consider getting rid of the VE-100?
Is it perhaps a bad place to tape the temp probes at the start of the tape and best to move them to the middle?

Any suggestions please comment.

Quote:

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Originally Posted by C2tcardin

Here is my current setup:
6 tub (28q) PVC rack with 4" THG heat tape. Thermostat is a Vivarium VE-100, I also have a Thermoworks (TW) 2 probe digital thermometer and for double checking temps and humidity I have another digital thermometer in the rack. I use aspen bedding, and have two hide boxes per tub.

So the VE-100 is set to 93deg (probe for the VE-100 was reading 92 at the time I checked temps which is fine it can drop by 2 degrees before kicking back on).
I have taped the probe for the VE-100 and one of the probes for the TW right to the THG heat tape next to each other near the beginning of the heat tapes run through my rack. The probe for the TW was reading 95 at the time the VE-100 was reading 92 so that's a bit upsetting. Inside the rack the other TW probe and the backup temp probe were reading 86 and 87 degrees respectively.
Today I took my IR temp gun and pulled each tub out to spot check the hot spot and cool spot temps. Starting from the top tub, which I labeled #1 down to tub #6 here are the hot and cool side reading I got.
#1: 90/83
#2: 95/83
#3: 95/86
#4: 97/85
#5: 96/84
#6: 96/84

So my fear is that things are too hot, though several of the snakes seem just fine hanging out in their hot side hide boxes.

Is this something wrong with the heat tape or the VE-100?
Should I consider changing to 3" heat tape?
Should I consider getting rid of the VE-100?
Is it perhaps a bad place to tape the temp probes at the start of the tape and best to move them to the middle?

Any suggestions please comment.

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This is strange. Since heat rises my top tubs are usually a bit warmer than the bottom tubs. I'd pull out all the tubs and check the temps along the tape to see if they are holding true. Since your temps are so much hotter at the bottom I'm guessing the tape is faulty and needs to be replaced.

I would have expected the same as far as the top tub being the hottest not the coolest. I've lowered the VE-100 by 2 degrees and will spot check everything tonight to see if the temps come down and if they're still giving the same strange results. As a backup I ordered a Herpstat 4 to be safe, I'll need it in the future anyway so why not grab it now in case. I'll use your idea too and take the tapes direct temps to see if the reading are the same.

If I understand correctly you have the tstat probe at the start of the tape.

You should get more uniform numbers by mounting the probe on one of the middle tubs. I would try 3 or 4.

You are correct, I'll move the probes tonight after measuring again and then check in the morning.

I have always wired my heat tape to put the power cord wired into the middle and not the start. I have had great temps then.

Well with the VE-100 temp lowered to 91 and the probe moved down to tub 3 in the middle of the rack I got the following reading today.
VE-100 probe reading 93 (it had just been cycled on)
TW probe reading 95
#1: 86.2
#2: 88.7
#3: 89.4
#4: 89.5
#5: 87.8
#6: 87.2

Ambient temps are all within about 2 degrees so I'm not concerned about them any more.

One thing I just changed was the tape I used to secure both the TW and VE-100 probes, I used Aluminum tape before and when I moved them last night. I'm wondering if this is what is giving some of the strange readings so I removed the aluminum tape and replaced it clear packing tape. I'll check tonight to see where things are.

That's better than you were getting. The only other thing that would make them closers upgrading to a proportional tstat one day.

As for the foil tape its good, I use it, but you want to make sure not to cover the probe with it and only secure the base of the probe and wire.

Quote:

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Originally Posted by KMG

That's better than you were getting. The only other thing that would make them closers upgrading to a proportional tstat one day.

As for the foil tape its good, I use it, but you want to make sure not to cover the probe with it and only secure the base of the probe and wire.

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Thanks, I have a Herpstat 4 on its way. Decided I didn't want to chance anything plus I was going to need it eventually. I was taping the probes right down (covering them) so I'll be sure when I redo my rack this week (when the Herpstat 4 arrives) that I tape the leads down not the probes.

You will enjoy the 4. I have one and love it. It does way more then I will ever need.