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I am in the process of testing my incubator for the season. It is a dorm fridge converted with a UTH on the back (top), and one on the back (bottom). There is a computer fan on the ceiling blowing down on the egg tubs. The UTH's are controlled by a Helix DBS 1000. I have it set at 89, and yet it allows the temps to reach 93.....why????? I understand I could just lower the 89 to 85, but I shouldn't have to.

The probe is hanging down from the ceiling just above the egg tubs. I understand that many of you feel ill towards the Helix, but It is what I have to use this year, so please just give me some ideas to fix the problem.

The fan causes heat. In a small incubator, if the fan runs when the t-stat shuts off the heating element, the heat from the fan alone can cause the temps to keep rising. I'm guessing your helix doesn't control your fan, because a proportional t-stat is not designed to run a motor, only heater loads.

Could I just plug the fan into the t-stat as well, and have the fan turn off with the heat? The dbs1000 has 3 plug slots.

The fan can't be controlled by a proportional t-stat. Proportional t-stats go up and down like a light dimmer, the fan is not designed for that. If you had a Johnson or other on/off type of t-stat that would work. I prefer two t-stats anyway. You could get a Johnson and plug the helix in to the Johnson, and the fan also into the Johnson. The heat would plug in to the helix.
Mike

Thank you for your reply. I will probably get a jhonson for next year.

>>Could I just plug the fan into the t-stat as well, and have the fan turn off with the heat? The dbs1000 has 3 plug slots.

Just scrap using a ac powered fan..As even if you do plug it into an on/off t-stat,the fan will retain heat in between.Which will create a hotspot(,which is what the fan was there to avoid in the first place.)

Just go get a couple of 80mm pc case fans(,that do NOT create heat since they are dc powered and brushless.)..Then go digging around your closets to see what types of dc converters you have laying around...Then just look on the back of them to see what milliamp/"Ma" they are rated for..
Most 80mm fans draw 150ma so it's best to use a dc converter that is rated at least to 300ma (If you use one that is rated at 150ma or less,then it WILL fail,and be hot enough to be hazardous as well.So double or even triple the rating is the goal.) So you see when dealing in dc powered fans it isn't the fan that could get hot,but the converter.

Also,if the dc converter says 12v on it,then the 12volt fan will run at its appropriate speed..If it says 9v on the converter then the fan will simply run slower.

All of my heating elements are at the bottom of my standup freezer/incubator..,with two fans on the door.One at the top blowing down the front,and the other at the bottom blowing towards the back(over the heating elements.)..Then the heat helps in raising the air up the backside again.

Good luck,have fun!
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Charles Glaspie
picasaweb.google.com/coldthumb

Thanks, I will take a trip to the science store. I am lucky enough to live close to a really cool science store that has all kinds of replacement parts for electronics and things you never even realized existed. It's one of my favorite stores.

Yes a proportional thermostat can control a fan. It's a 120v output, so no problem with that. But there is no use to it.

You also DON'T WANT TO CONNECT the fan with the thermostat.

WHY : Cause the fan will stop running when the heat stop. Meaning you won't have air movement and the temperature inside the incubator won't be all equal.

suggestion : find a fan that it's wattage is lower. It will produce less heat for the same amount of CFM.

Also, what's the temperature in the room the incubator is in. You should have your incubator in the coldest place of your house, not in the reptile room that is already heated. It will be easier to control that way.

If that doesn't work, and the incubator is really small, I suggest removing the fan and/or removing a part of the heat tape (or what else you are using for heat). If it's small, air movement shouldn't be much of a problem. If it's small and you are using to much heat element, you are creating spikes of temperatures.

Lastly, I would also check the temperatures in the incubator in any other way, may be your thermostat is offset, happens once in a while or if someone added an offset value to it. (That's the only way offsetting the value from 89 to 85 could work).
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love this world, don't hate it.

The same thing happened to me when I first set up my incubator. I was using a 120 volt AC computer fan. I realized it was generating heat that the stat could not control. Try using a DC powered computer fan. You can get them from Helix, CompUSA etc. Hope this helps.

Helix and CompUSA is too expensive for me. I am going to build my own from the science store. Thank you for your input. I never would have figured out the whole AC/DC thing.....lol.,....CAUSE IM TNT, IM DYNAMITE!!!..Sorry, couldn't resist.

is the probe the first thing that the moving air from the fan comes in contact with? also is there a constant blowing on the probe? that will cause an increase in temperature.

all the fan needs to do is circulate the air within the incubator slightly, not violently.

try to move the probe and lower the speed of the fan.

...also you might want to place the probe within a dummy tub so that the temperature is being read from within the tub and not the incubator.

Pitoon

>>I am in the process of testing my incubator for the season. It is a dorm fridge converted with a UTH on the back (top), and one on the back (bottom). There is a computer fan on the ceiling blowing down on the egg tubs. The UTH's are controlled by a Helix DBS 1000. I have it set at 89, and yet it allows the temps to reach 93.....why????? I understand I could just lower the 89 to 85, but I shouldn't have to.
>>
>>The probe is hanging down from the ceiling just above the egg tubs. I understand that many of you feel ill towards the Helix, but It is what I have to use this year, so please just give me some ideas to fix the problem.
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Thats a good idea about the probe in a dummy box. Yes, the fan is blowing on the probe. That makes sense. I think I am going to relocate the new fan that I put together to the bottom.

find yourself a small 5 volt or 12 volt computer fan. you can use a potentiometer to control the speed of it.

Pitoon

>>Thats a good idea about the probe in a dummy box. Yes, the fan is blowing on the probe. That makes sense. I think I am going to relocate the new fan that I put together to the bottom.
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Homepage
My BLOG
2011 European Shows