# Basking Temps droping when heating is on?



## TheHouseofReptilez (Sep 26, 2021)

I don't know if it's just me or does this happen to anyone else I have my basking temp set at 32c and it holds steady but when the central heating is on in the house the basking temp drops to 30c - 29c should it be doing that?

I thought it would stay at a consistant 32c but I guess I was wrong I'm presuming it does this to keep the viv at the right temp either that or I'm doing something wrong,

I've searched all over for an awnser to this but have came up short so figured I'd ask here, So if anyone can help that be great.

Thanks.


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## CrazyFrog (Dec 19, 2021)

Mine does that for my carpet python with temp set to 32. It drops to 29 or 28 when i have central heating on.

I assumed it was something to do with the thermostat having a higher air temp (turning off and on more) , and the temps from the central heating going up and down.


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## TheHouseofReptilez (Sep 26, 2021)

CrazyFrog said:


> Mine does that for my carpet python with temp set to 32. It drops to 29 or 28 when i have central heating on.
> 
> I assumed it was something to do with the thermostat having a higher air temp (turning off and on more) , and the temps from the central heating going up and down.


Glad I'm not the only one it happens too I thought it was strange but the more I think it makes more sense when the temp in the room gets up the bulb stops giving off as much heat to maintain the correct temp inside the viv only issue is when the bulb dims down and it stops producing as much heat the thermometer reading drops although the viv stays at a consistent temp.


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## Malc (Oct 27, 2009)

ThatCornSnakeGuy said:


> I don't know if it's just me or does this happen to anyone else I have my basking temp set at 32c and it holds steady but when the central heating is on in the house the basking temp drops to 30c - 29c should it be doing that?
> 
> I thought it would stay at a consistant 32c but I guess I was wrong I'm presuming it does this to keep the viv at the right temp either that or I'm doing something wrong,
> 
> ...


Depends where the thermostat probe is, how narrow the thermal gradient in the viv is, and a dozen other factors. If the thermal gradient in the viv is such that the cool end matches the ambient room temperature then when the heating is on the rise in the room temp means the thermostat has to work less as the thermal gradient in the viv is decreased. If you have the probe directly under the CHE there is less change as you are measuring the actual hot spot rather then the ambient air away form the heater. probe placement is covered in the sticky at the top of the snake section.

So long as there is a thermal gradient within the viv, allowing the snake to warm up or cool down then that's all that matters, as in this case the slight drop of a degree or two isn't long term, and to be honest nothing to really worry about even for tropical species such as Royals.


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## TheHouseofReptilez (Sep 26, 2021)

Malc said:


> Depends where the thermostat probe is, how narrow the thermal gradient in the viv is, and a dozen other factors. If the thermal gradient in the viv is such that the cool end matches the ambient room temperature then when the heating is on the rise in the room temp means the thermostat has to work less as the thermal gradient in the viv is decreased. If you have the probe directly under the CHE there is less change as you are measuring the actual hot spot rather then the ambient air away form the heater. probe placement is covered in the sticky at the top of the snake section.
> 
> So long as there is a thermal gradient within the viv, allowing the snake to warm up or cool down then that's all that matters, as in this case the slight drop of a degree or two isn't long term, and to be honest nothing to really worry about even for tropical species such as Royals.


I had the probe placed about 4inches away from the basking spot thermostat was set to 22c which is what the air temp in the room reaches when the heating is on moved the probe closer to the basking spot and put the thermostat to 26c now I'm getting temps of 32c - 33c even when the heating is on my only concern now is that when the lights go out and the night time temp drop happens in the morning when they kick back on once it hits the 26c on the stat that it'll read to hot and cut off.


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## Malc (Oct 27, 2009)

If you are using a pulse proportional stat to control a CHE with the probe close to the CHE as suggested then it will maintain the target temperature even when the central heating is turned off at night. If you have an overnight temperature drop, or turn the heating in the viv off at night, then there will be an overshoot in the mornings when the CHE is energised for the first time. However the overshoot is slight and not as dramatic as a basic on/off stat, because by design the stat starts reducing the on time each pulse when nearing the set point.

When I was developing my own pulse proportional stat I had loads of graphs showing the overshoot etc whilst testing. Sadly that was almost 13 years ago and no longer have them to hand. Again, you are over thinking things... if you are using mats and a on/off stat then even when it gets turned off the mat will stay warm until it starts to trigger the stat once more


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## TheHouseofReptilez (Sep 26, 2021)

Malc said:


> If you are using a pulse proportional stat to control a CHE with the probe close to the CHE as suggested then it will maintain the target temperature even when the central heating is turned off at night. If you have an overnight temperature drop, or turn the heating in the viv off at night, then there will be an overshoot in the mornings when the CHE is energised for the first time. However the overshoot is slight and not as dramatic as a basic on/off stat, because by design the stat starts reducing the on time each pulse when nearing the set point.
> 
> When I was developing my own pulse proportional stat I had loads of graphs showing the overshoot etc whilst testing. Sadly that was almost 13 years ago and no longer have them to hand. Again, you are over thinking things... if you are using mats and a on/off stat then even when it gets turned off the mat will stay warm until it starts to trigger the stat once more


I'm using a halogen bulb on dimming mode 12 hours on 12 hours off have the stat set at 24c which gives me a basking temp of 31c - 32c had the overshoot this morning it hit 54c then dropped down to 37c and wouldn't move from there,

If I move the probe any closer to the basking area when the stat turns on in the morning it heats the probe to where it just shuts off.


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## Malc (Oct 27, 2009)

Guess it will be just a case of experimenting with probe placement. What happens if you place the probe directly under the lamp (will have to re-adjust the stat). Overshoot was one of the reasons I developed my own thermostats years ago. Getting the balance right so that any overshoot was minimal with commercial stats was often hit and miss.


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## CrazyFrog (Dec 19, 2021)

Malc said:


> Guess it will be just a case of experimenting with probe placement. What happens if you place the probe directly under the lamp (will have to re-adjust the stat). Overshoot was one of the reasons I developed my own thermostats years ago. Getting the balance right so that any overshoot was minimal with commercial stats was often hit and miss.


Don't suppose you sell thermostat's that you've developed?


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## TheHouseofReptilez (Sep 26, 2021)

Malc said:


> Guess it will be just a case of experimenting with probe placement. What happens if you place the probe directly under the lamp (will have to re-adjust the stat). Overshoot was one of the reasons I developed my own thermostats years ago. Getting the balance right so that any overshoot was minimal with commercial stats was often hit and miss.


The temp drop over night is around 7 or 8 degrees so when the stat kicks in on the morning if the probe is placed under the basking area it just heats up and cuts off it's actually becoming a pain in the neck to deal with now.


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## Malc (Oct 27, 2009)

CrazyFrog said:


> Don't suppose you sell thermostat's that you've developed?


Sadly not.... to much legislation and hoops to jump through to be in a position where I could sell one


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## Malc (Oct 27, 2009)

ThatCornSnakeGuy said:


> The temp drop over night is around 7 or 8 degrees so when the stat kicks in on the morning if the probe is placed under the basking area it just heats up and cuts off it's actually becoming a pain in the neck to deal with now.


Irrespective of the thermostats design the basic function is to have the probe control the output in relation to the set point. Part of the problem is that they have no idea how responsive the heating element is, and in a like for like situation, a 150w halogen may overshoot dramatically where a 75w one is more controllable. I don't have all the answers, but I've always found dimmer stats and lamps harder to get right and "dialled in" than a CHE on a pulse proportional.


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## TheHouseofReptilez (Sep 26, 2021)

Malc said:


> Irrespective of the thermostats design the basic function is to have the probe control the output in relation to the set point. Part of the problem is that they have no idea how responsive the heating element is, and in a like for like situation, a 150w halogen may overshoot dramatically where a 75w one is more controllable. I don't have all the answers, but I've always found dimmer stats and lamps harder to get right and "dialled in" than a CHE on a pulse proportional.


Lucky for me the stat I use has all three functions built into it On/Off, Dimming and Pulse proportional,

The bulb is pretty much irrelevant as I already have a LED bar inside the enclosure providing light so I think in the next week when payday rolls around I'm going to switch out to a 75w CHE and hope my temp overshoot issue is resolved.


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