BP Heating Trouble PT2: Electric Boogaloo

Sorry about the punny title, but humour is generally how I approach stressful problems. Currently I have (at least in my newbie eyes) a pretty large one. I just got a BP a few weeks ago and everything was fine. The average heat on the warm side was 31C and cool side was 26C. All the equipment was new and working smoothly. Barely a month later, however, and the average air temp on the warm side has slowly begun to cool. At first it was gradual, then all of a sudden today it plummeted from 28C in the morning to 25C now! I checked the poster board for faults and found nothing, the che is brand new, I covered the screen top in aluminum foil and nothing has changed since I had first obtained my new snake. I just fed him a couple days ago before the plummet but it was 28C at the time, it’s a miracle he hasn’t vomited his food up. My best guess is that I screwed the bulb in incorrectly and it’s slowly come loose over the course of a few weeks. Does anyone else have experience with this kind of odd situation?!

Have you tightened the CHE & is it now providing the right temperature? & no, that's never happened to me.

It might also be a defective CHE, or else it's wearing out fast- or maybe a loose connection someplace? Is the fixture adequately rated for the heat & wattage?

After confirming that it is fully screwed in, the CHE can be further checked by checking its temp with an IR temp gun (either you have an IR temp gun, or you need one ASAP) while the thermostat shows that it is powered. If the thermostat is supplying power, the CHE should be hot, and as the thermostat cycles power to the CHE the IR gun should show the temp changing accordingly.

If the thermostat is always powering the CHE, and the temp does not maintain at the set point temp, then the CHE is inadequate to heat the enclosure given the enclosure setup and room temp.

It is certainly possible that a CHE that is moved whenever the top of the enclosure is accessed could work itself loose.

It would be prudent to check whether the thermostat is functioning correctly -- probe securely in place, current temp on the thermostat is confirmed with the IR gun, and so on.

I doubt the Che is defective, considering it heated the warm side adequately during the first couple weeks or so of use. I’ve rescrewed the bulb into place though it still isn’t providing correct temps. I did somewhat find a work around, however, by raising the heat May temp up to provide warm-side temps. Effectively swapping the cool and warm sides. I did this last night and my snake appears to be thermoregulating more. Since instead of staying near the warmest spot he could find, he’s been moving between the 2. Now the cold side temps are 27C, and the warm side temps are 32C.

CHEs can fail after working well. They're just a resistance element imbedded in ceramic, and resistance elements can fail over time from simple wear (element deteriorates) or from vibration (element breaks).