Do you have a cool side for you snake or is the whole viv 87? Because if there is a cool side then the vine sleeping is likely not due to the 87 degree warm side, it will just be due to the little one liking to climb as some due.
Having said that though, your warm side temp issue can be fixed with either a rheostat or a thermostat and a digital thermometer or temp gun to ensure the rehostat or thermostat is keeping the temp where you want it. This is what I posted on another thread about these items.
Thermometers-Just so you know those round dial and the strip thermometers are notorious for be out by anywhere from 10-20 degrees above or below what they are telling you.
So if they tell you it is 83, it could really be as different as 63 or 103!!! Very bad. So you will want to use either digital thermometers with probes or an infrared temp gun(most accurate). If you think that at some time you will have more than one snake, skip getting the thermometer with the probe and just get an infrared temp gun. This will save you money in the long run. I say this because you can by digital thermometers with probes(optimally, 2 per enclosure one for warm side and one for cool side, minimally, 1 each enclosure for the warm side) for each snake or you can buy one gun and easily go from enclosure to enclosure and check everybody's temp with complete accuracy. This has saved me lots of money I would have had to by a minimum of 8 and optimally, 16 digital thermometers with probes by now at say $10 for cheap ones that is $80-$160 before taxes and my temp gun on sale was $30.(Just my opinion)
As for lamp dimmer rheostats, I have 9 of those exact lamp dimmers going in this house. The snakes are all in different rooms and some are on the main floor and some are in the basement(so various different ambient temps) I have no trouble with them at all(all but one of my UTH's are ZooMed Desert so they easily get to 120+ if left unregulated). After about a week or two of learning how much ambient temp fluctuation will cause a change in the temp of your viv, you will know when you need to check and change the dimmer.
Simply, plug it in and start with the slider about 1/3 of the way up from the cord, this way you should likely get a temp that is lower than your desired temp vs. a temp higher than your desired temp. Now wait about 1-2 hrs, and make sure you have the warm side hide on top of the UTH because will retain heat and cause the temp in that area to be warmer than in other areas of the UTH. After 1-2 hrs, check temp in the warm side hide. If using a thermometer the probe should be siliconed to the bottom of the glass where you hide is going to be as that is where you snake is going to be. If using temp gun, lift the warm hide and check the temp right on the bare glass or plastic.
Now if your temp is not at 83-85 adjust the dimmer accordingly, know that the dimmer is very sensitive and the smallest movement can make a big difference in the temp to the UTH. I always make just the slightest movement and then check again in an hour. Once you have reached the desired temp, check it every few hours or at least 2-3 times the first couple of days until you see how stable your house temps seem to be and how they affect the dimmer and UTH.
If you notice that there is a day in the house that it gets noticeably warmer, you will need to check the temps and likely lower the dimmer slightly and a day that is noticeably colder will also require a temp check and usually a slight increase to the dimmer.
The reason this happens is because a dimmer does not actually regulate in a manner where you can input a temp you want and a computer chip and probe check the temps and adjust power to the UTH accordingly to maintain the stable temp. Instead what your rheostat does is limits the amount of power going to the UTH so that you can then check the temp that it creates with it's limited amount of power, thus being able to create a desired temp. BUT when the ambient temp changes enough then the UTH's temp will fluctuate as well because you originally had the amount of power flow limited to create a temp for the ambient temp you had previously.
For those who do not want to deal with the adjustments required by using a rheostat then a thermostat is definitely the way to go. Some refer to thermostats as being "set it and forget it", they are sort of like this but that mentality can potentially cause damage or injury to your snakes.
Thermostats, have a computer chip that allow you to set a desired temp, they also work with a probe so that the chip can then get read outs from the UTH and know whether it is at the desired temp. If the UTH is not at the desired temp it will either limit/increase power until it gets the correct temp or it will shut of the power and then turn it back on when needed. Thus the simplicity of the thermostat and the "set it and forget it" saying.
Potential problems arise when a person believes the "set it and forget it" thinking because it has a computer chip in it therefore it can not fail. All electronics, thermostats, rheostats, stereos, microwaves etc. can and do fail! Thus even with a thermostat you still need either digital thermometers or a temp gun to double check the temps in the enclosures and you will need to check on them to ensure that the thermostat does not fail. Some people who use thermostats, actually hook up two, one as the main unit to set the temp and one as a back up(set with a slightly higher temp still in a safe range for the snakes so that if the first fails it will kick in when the UTh hits that temp)as a fail safe.
I have read on here where people have lost snakes to thermostat failures, in fact entire collections and I myself have had one lamp dimmer fail, so far(luckily no loss as I check on my temps every couple of days and my snake just refused to go to the warm side). So I can not stress enough check temps frequently, get accurate thermometers or a temp gun and regulate the UTH.
If you have already got the tank set up with these heat regulating and checking items, then you need to either consider how warm you keep your home/apartment and if there is a cooler area of your dwelling that you could put the tank in to help keep the UTH temp lower.
Hope this helps some, I know it is long but I thought the detail might be appreciated.
