Home built cabinet incubator question.. HELP please

[sara]

I'm working on a cabinet style incubator. I purchased the wafer thermostat and heating element for a Sportsman cabinet incubator. I'm trying to get the thing to hold temperature. It warms up to 99.5, but then shuts off. It turns back on, but my thermometer will show a 3 or 4 degree drop during that time? Any suggestions..

ETA: I have a fan in it.

 

[minna]

How long have you let it run? Sometimes mine takes a bit to regulate it's self.

 

[twigg]

Sounds like it is working fine.

Set it to warm 2F higher, and check the temp with a water wiggler. A 4 degree swing around the set point will not e an issue at all

 

[jvls1942]

the reason for the temp drop rests in our wafer.. it is not contracting fast enough.. the button on your micro switch has a distance to travel governed by the expansion and contraction of the wafer.. the only way to correct this is to try a different wafer..(don't tell me that you have a new wafer) that does not make any difference.. some wafers are just slower than others.

OR try to find a dual wafer.. that is two wafers stacked together..

OR maybe your micro switch button just has a long travel.. try a different switch..

OR set your temp to a higher setting but not over 101....

 

[sara]

twigg~ That's a good idea, I don't use a wiggler normally. However it would tell me if the eggs are going to remain a constant temperature. It did put a bottle of water in it, but that didn't really do anything. I thought it might make it hold the heat for a while. Maybe it's not enough.

 

[twigg]

The problem you always have is trying to understand what is going on in the egg.

You heat the air, and this is no indication, because it fluctuates (it HAS to fluctuate for your thermostat to work)

With a simple mechanical switch like a wafer, this shift can e substantial.

The wiggler will call it as the egg sees it. Cheap, simple, accurate.

Another way around this is to use a proportional temp. controller. This will heat the air to the required temp, and keep it there. You wouldn't need a wiggler because there would be no fluctuation to speak of. With the door kept closed, they can regulate to within 1/10th of a degree F

 

[sara]

jvls1942 ~ I'm going to order some spares, so I'll try one when I get them in.

 

[jvls1942]

Quote:
it is nice to be acknowledged,

 

[rebelcowboysnb]

Is the wafer in the air path of the fan or off to the side? If the air from the fan goes directly across the wafer it will react to the temperature quicker an have a smaller temperature swing.

 

[twigg]

Quote:
The wafer reacts to temp, not air flow or anything else.

If the incubator is well designed, then there should be very few areas inside where the air is not moving, neither should there e a temperature gradient.

If the wafer reacts differently in front of the fan, then the incubator has other problems as well.