A Central Air Heating Element, A PID and a Sauna

[diif]

Still no signs of anything safe.
You can't blow too much air into a sealed room.

[JayPoorJay]

Still no signs of anything safe.
You can't blow too much air into a sealed room.

Saunas are built vented in 2 spots.

I admit, it all sounds pretty crazy,,, and sketchy even but as I've said and will say again I will not move forward, from either planning OR in the physical IF things don't add up and doesn't seem to be able to be done safely. How many ways can I express that?

[diif]

If its vented then any heat is going to be blown stright out? Also heat rises, it makes no sense having the heat in at the top.
All of the different heaters I see for saunas, they are all inside the sauna. I don't see anyone trying to heat one by blowing hot air in. There is a reason for this.
Your heater goes wrong and there is a fire, it's too late by the time you realise, regardless of how many times you write "I'm only doing it if its 100% safe". The difference in price compared to the overall cost of the whole sauna seems minimal when 6KW heaters are available on Amazon from $399.
Your house insurance might also be void if you are doing dumb shit in their eyes to possibly save a few beans.
Ignoring physics and safety, you have to see that your 2-5KW cooker top, ghetto heat system is vastly inefficient compared to a heater sitting in the sauna heating already hot air.
I'm all for making stuff and saving a few beans bit practically, the time building the thing, adding heating controls and safety features, the inefficiency in the design, it doesn't seem worth trying.

[JayPoorJay]

Sam... HellO. You wrote me a super long and well written message that I somehow missed completely... I have to go back and will follow up the best I can. Then,,,

Diff... I'll just go along with you, and try and answer...

Point blank. Vents and ventilation in saunas is vital. Not easy to get right, and can add significantly or take away from the saunas function. There is a science to it. Point is, venting saunas is well documented. Look it up. And no, the heat doesn't just escape.

Second, the reason that saunas have 2 and 3 benches at different levels/heights is because, as you pointed out, heat rises, and in that, if you sit up top (top bench) you get max heat, then you can always go down a bench, and then back up, or down, then down again if you start overheating. I've been in saunas where folks will actually resort to laying on the floor a while to escape the heat at upper levels. Point is, heat starting up top and being more concentrated up top is not a bad thing....it's desired....the norm.

Actually,,, my worry is forced air (which will only be part of this thing because I DO plan on having a 200$ Vevor Sauna Heater in the unit as well) will mix/stir the air too much. Layered still air is a good thing. My hope is to have slow but steady air stream and a fan that will self slow or speed up depending on what the PID Controller is saying.

If I can ever figure this out, if I can, I have a lot of productive positive thinking to do... I thank you for trying to help, but you ain't helping. Jus say'n... If you point out a problem, a mistake, I'm all for that, but what I expect after criticism, an offered solution, or something close to one. I came here for YOUR expertise. You haven't really offered many solutions to problems.

One of the problems with ANY plug in unit (as opposed to a strong and hearty steel wood stove with large rocks or rock plates on top like the saunas I visit in Finland) is that they take forever to heat up, more than an hour in some cases and that costs a TON of money and is bad for the environment. Then, as soon as the door is opened with a plug in unit, a ton of heat floods out and then it takes a ton of time for recovery. Any sauna heater for the sauna size I want costs in the $1000s, not 400$...

I hope to solve that long warm up and heat loss issue with doors with this set up... But again, I may NEVER go forward because,,, well this is just R and D at this point.

Sorry brother Diif,,, your facts are not facts.

[diif]

I have to admit to only watching a few DIY sauna videos but my understanding of heat seems to be a bit better than yours
You claiming your idea is better than a commercial offering is clearly very wrong.
I wish you all the luck but your idea won't work. All your words do nothing to change the laws of thermodynamics.

[JayPoorJay]

I have to admit to only watching a few DIY sauna videos but my understanding of heat seems to be a bit better than yours
You claiming your idea is better than a commercial offering is clearly very wrong.
I wish you all the luck but your idea won't work. All your words do nothing to change the laws of thermodynamics.

Please tell me your ideas about heat... What do I need to know or understand??? That's why I came here with questions.

[sam_sam_sam]

I think your best bet is if you can find a used that either works but your better bet is if you can find one that does not work for free or very little money and carefully take it apart and see how it is made and see what could be wrong with it and attempt to repair it then you would have best of both worlds you would know what is inside of and how it works

This what and how I go about doing something that I do not want to spend a lot of money on something that I am not sure if I want to go down a certain rabbit hole either because it might not work the way I expect it to or because it going to cost to much money for how I want it to work or my expectations are unrealistic

But by doing it this way I have learned something and I have not spent a bunch of money that is not going to be used and just sitting somewhere collecting dust

[JayPoorJay]

I think your best bet is if you can find a used that either works but your better bet is if you can find one that does not work for free or very little money and carefully take it apart and see how it is made and see what could be wrong with it and attempt to repair it then you would have best of both worlds you would know what is inside of and how it works

This what and how I go about doing something that I do not want to spend a lot of money on something that I am not sure if I want to go down a certain rabbit hole either because it might not work the way I expect it to or because it going to cost to much money for how I want it to work or my expectations are unrealistic

But by doing it this way I have learned something and I have not spent a bunch of money that is not going to be used and just sitting somewhere collecting dust

Understood... Thank you 🙂

[JayPoorJay]

I'm looking at this on eBay...
I think I'm going to give it a shot...
Keep exploring the idea(s)...

Anyways,,,

Forced air for fast heat up with a unit pushing in air on the outside of the space supplemented with a purchased unit (probably used) with rocks and such on the inside to keep the temps up once reached is the idea. We shall see.


https://www.ebay.com/itm/37518545488...mis&media=COPY

[diif]

Just get a Helo element and put it inside the sauna. Forcing in air won't work.

[sam_sam_sam]

I have to admit to only watching a few DIY sauna videos but my understanding of heat seems to be a bit better than yours
You claiming your idea is better than a commercial offering is clearly very wrong.
I wish you all the luck but your idea won't work. All your words do nothing to change the laws of thermodynamics.

I would agree with you on this topic

Please tell me your ideas about heat... What do I need to know or understand??? That's why I came here with questions.

JayPoorJay

This is where you need to google what you do not understand I can not say that I completely understand “laws of thermodynamics.” Which if I was undertaking this process the understanding of what it takes to make this project to work I would also need to understand this as well
This goes back to the original comment that I made about understanding limitations and how the systems should work

One thing I caution you about is not to take shortcuts when it comes to fully understanding the limitations of the systems that are involved like thermo-dynamics , heating elements the different types the different types temperature switches temperature sensors and PID controllers there might be other systems that you have not even thought of yet at this point because if they are over looked you might be asking for failure of some type this would not be good situation to be in and not good way to do a proof of concept especially for the potential risk of fire I personally would want to understand as much as possible can about this situation and subject as I can

I can tell you that I have done this in the past and done things that were not fully understood and things did not turn out the way it anticipated it to turn out and it could have been disastrous if I did not have enough common sense to know that I was going down the wrong rabbit hole and a lot of times I just stop doing that project because I consider it to be to dangerous to do and not worth the risk or just did not understand what I need to know or just did not have the time to devote to the project that I had in mind to do

One other thing I would caution you about is be very open minded to thing that you might not have even consider to be involved with what you are planning on doing it is a temptation to do trust me I been there before as well and sometimes it bites you in the ass
This situation is not easily overcome you have to rise to the occasion and realize that you might be asking for trouble down the road if you find yourself not being open minded enough for the situation

Tell you a story that happened to me yesterday my son wanted me to adjust the clutch on his semi truck well guess what I have never done this before I have done cars and small trucks before so what does my son do he send me a couple of YouTube video on the subject and the first video was on how to use the tool that is made for this job easier to do but probably very expensive to buy the second video showed the common tools that a truck mechanic would have in there toolbox but the video was not the best because you could not really see what the person was referring to but the video after that one showed sitting on a stand and had parts of it cut away so you clearly see what he was talking about and showed clearly and my son was the one that adjusted his own clutch on his own truck and I supervised the process and walked him through the process of how to do this repair

The reason I told this story is because yes I have been a mechanic for several years and still do it from time to time but this is where even though I have never done it before but because I understand how a clutch operates and what the components are yes there is one more item that is on a semi that is not on a small vehicle is clutch brake but in the video that I watched he basically and briefly explain how it works and what it does so I could completely understand how and what it takes to do this job safely and correctly

One note on all three video's it says to do 10 turns on the adjustment bolt but I told my son not to do it this way do only 5 turns and the reason being is that you do not want to load the spring more than you need to meaning that you do not want to take tension off the springs once you load them so 10 X 2 would have been 20 turns but doing it 5 X 3 would be 15 turns and the adjustment was very close to what it needed to so I told him to do 3 more for a total of 18 turns now how many people would know that about clutch springs not very people would trust me

One other note even in the last video he dose not mention anything about loading and unloading springs tension which I was surprised by because this is another issue with because you have done something so many times and the majority of times it might very well be that you have to do it 20 turns to make adjustment that needs to be done but in all fairness he did mention that if you make the adjustment to much just go in the opposite direction and correct the adjustment

[diif]

If you are trying to heat up your sauna as quickly as possible then it's ventilation ducts are closed. This means the room is under pressure, if you are forcing air in. If you open the door to enter, the heat comes out. Turn off the fan and any heat that has collected at the ceiling is pushed out the way it came in.

[sam_sam_sam]

If you are trying to heat up your sauna as quickly as possible then it's ventilation ducts are closed. This means the room is under pressure, if you are forcing air in. If you open the door to enter, the heat comes out. Turn off the fan and any heat that has collected at the ceiling is pushed out the way it came in.

JayPoorJay

This is very true and something that needs to be considered when you are planning and designing your space and if you are planning on doing so many CFM air change per hour now this is not necessarily an issue if you are doing the heating with electricity if you are doing it propane or natural gas you do need to consider that you need to have a certain amount of air changes per hour for safety reasons in case you have a chamber leaking issue that you are not aware of note about this you need to test for carbon monoxide contraction par per million to eliminate the possibility of this issue

[JayPoorJay]

Good morning Guys...

An ongoing issue with saunas no matter how one heats them is heat loss when a door opens. No matter what kind of heat source. I understand that unlike a space without lightly pressurized air, heat loss will be a bit quicker. A lot depends on materials in the room retaining heat, residual heat. The wood will do some, the Vevor heater with 80lbs of stone INSIDE of the space will do lots.

Who said anything about propane or gas???

I have this controller and want to see if I can get it working on the enclosed element furnace brick fan stack. Do y'all care to see the ED for the unit? I could use some help with the T's and understanding wiring it up.

[JayPoorJay]

This is all the company that I contacted had

This is challenging, lol

[JayPoorJay]

Looks like the thermostat (capillary bulb style) is necessary and controls the on off. The guy who supplied the ED gave me a part number for the thermostat BUT the thing is like 100bucks...! I'll go dig that number up (they are readily available) and it's like companies KNOW that people are using them for saunas so I'm wondering if there is a capillary style thermostat (or even a digital one) that can be used in its place...? Any ideas?

(edit) The numbers...
Timer 3140-505
Tstat 3155-623

Light 3160-118

Knob timer 2140-578

[JayPoorJay]

Can you help me decipher "limit control leads in heater junction box"? Circled in orange in the attached image.

[sam_sam_sam]

You need to be careful about using the wrong type of “thermostat (capillary bulb style) is necessary and controls the on off”
Two reasons one is the contacts of the switch part that can handle the current the other concern is the temperature range of the device plus and the dead zone of the thermostat sensitivity to temperature change these are different do not think that they are the same because they are not

You could probably go with a digital thermostat however you will need to experiment with the temperature on and temperature off and the dead band to keep the system from short cycling which is a detrimental effect on mechanical switch type of contacts

Now you use a sold state relay instead of a mechanical switch type but you still need to have a dead band where you have no ON/OFF state because even if it is digital type of switch you can still overheat the module even if you have a heat sink on it

Now this would require a PID controller to have the best possible result you could possibly do it with out a PID controller but you would have to have the right type of temperature controller that can handle the current rating of the heater unit but if you are using this type you need to know the amount of dead band the temperature controller you plan on using not all of them are the same the best ones are the ones that you can set the ON temperature and you can set the OFF temperature of the heater unit this is the best type to use now some of them have what temperature off set which a predetermined difference between ON and OFF which still can be used but make sure that you have at least 20 degrees difference at a minimum for best results

Now they do make thermostats switches that can adjust the dead band to certain extent but this type of thermostats are more accurate and more expensive to buy that is the reason the thermostat that is recommended is more expensive than a general use thermostat type switch is

Here is something that I found on EBay that you might be interested in a non working heater unit

https://www.ebay.com/itm/40453572545...Bk9SR9SMiOGmYw

Ebay search “electric sauna heater 120 not working”

[diif]

Good morning Guys...

An ongoing issue with saunas no matter how one heats them is heat loss when a door opens. No matter what kind of heat source. I understand that unlike a space without lightly pressurized air, heat loss will be a bit quicker. A lot depends on materials in the room retaining heat, residual heat. The wood will do some, the Vevor heater with 80lbs of stone INSIDE of the space will do lots.

Obviously there is heat loss when you open the door but due to your pressure idea, it all comes out all at once. Forcing air in is a waste of time and energy.

[JayPoorJay]

Could this be my guy?
https://a.co/d/ab3gAph