Help with temperature...

[azn_baddie]

I built a cabinet incubator and I need help on increasing the lower tray temperature. The light mounted above the first tray with a computer fan and it is at 99.8 degrees and the lower tray is 96.5 degrees with a lower fan also. How can I increase second tray temperature? Please help.

 

[dbcooper02]

Would need a full description, size of cabinet, heat source, location and direction of fan, etc. or better yet pictures to come up with any useful advice. I would say that the purpose of the fan is to blend the air in the 'bator to make it all the same temp. What do you get if you turn off the lower fan?

 

[azn_baddie]

Ok, here are the specifications of my incubator along with pictures. Please help.

25"Hx18"Wx19"D 3/4" Birch plywood
60w light bulb
6" computer fan mounted on top blowing out towards the door
4" computer fan resting on bottom blowing towards the back

Please see pictures to get a better idea of it.

 

[dbcooper02]

Your incubator looks great. I'll do what i can to help you get it working right. I can tell you how a Sportsman is set up and see what might apply to yours. In a sportsman there is about a 3" air space between the front and rear of the egg trays and the door and rear wall respectively. The fan and heating element are mounted above a shelf about 4" above the top egg tray with a similar 3" gap at each end. There is a bulkhead above the shelf with a hole in the middle where the fan is mounted blowing forward across the heating element. A circulation of the heated air is created as the air blows forward, hits the door, drops down, and is pulled rearward and back up to the fan through the gap at the rear. In the Sportsman a pan of water is placed in front of the fan for humidity.
I can't really tell if you have any space between the ends of your egg trays and the front and rear walls, but I do have an idea you might like to try. Cut a piece of plywood that will rest on the cleats you have there above your top tray leaving about a 2" gap at the front and rear. Cut another piece that will create a bulkhead between the top of that shelf and the top of your cabinet. Cut an opening in the bulkhead to fit your larger fan and mount it there blowing forward. This should get the air circulating. I wouldn't use the second fan. If you would prefer you could mock this up with cardboard and masking tape to determine if it will work. Here's a pix of the Sportsman if my description isn't making sense. Hope this is of some help. Any questions, I'll do my best to help you out.
Doug

 

[azn_baddie]

Thank you dbcooper02 for taking your time to help me out. I will try it and see if that helps. I am thinking that my heat source and fan is not enough for my cabinet size. Should I increase it? I am also thinking about adding a forced air heater unit inside my cabinet. It is so frustrating that I can't get it to work correctly.

 

[dbcooper02]

After you get the air circulating if the temperature still isn't there I'd experiment with a 75 or 100 watt bulb. The heating element in the Sportsman is something like 225 watts. The cabinet volume of the Sportsman cabinet is roughly double that of yours.
db

 

[azn_baddie]

I put a plywood board on the very top shelf leaving 5" from the back and front for air flow. I increase the light bulb wattage to 90w and put in a more powerful fan resting on top of the board. This seems to increase the lower tray temperature close to the upper tray. The lower tray is about .50-.75 degrees lower than the top tray. Should I add another fan or increase the wattage on the light bulb or should I leave it? Thanks

 

[dbcooper02]

I'd try the bulkhead, even if you just make it out of cardboard to see if it helps. I believe it will improve the air circulation and even things out for you.

 

[aprophet]

on my homebuilt bators because I don,t have the bulkheads that a sportsman does I mounted my fan blowing up at the ceiling my theroy is this causes heat to wash down the sides I used 1" standoff spacers to get the fan away from the top a little . you might try 2 - 25 or 40 watt bulbs mounted in oppesite corners good luck . I am only on my third hath the first 2 were fairly sucessful