Erratic Humidity

[mmlaj]

Hello all. I am new to incubation. I used to have a smaller incubator but now I bought a much bigger one.But I am facing a problem controlling the humidity! This what happens:
The set up temperature and humidity are 38 C and 60% respectively. When the temperature goes above 38.2 C, a computer-fan-looking fan will turn on. Once this fan turns on, the humidity will sharply drop from 60% to 35-40%. This happens again and again and I am having no control over it. I live in a dry area where the humidity is around 20%. Does that have anything to do with it? I would really appreciate your help because I don't want to lose my precious eggs in the incubator !

 

[ChickenCanoe]

Low ambient humidity is a possible contributing factor. Perhaps the incubator humidity concentrates near the humidity sensor when the fan isn't running and then dissipates when the forced air fan kicks on.
I wouldn't worry about it. Average humidity is what you are looking for rather than constant humidity. In nature, humidity varies widely.
Humidity isn't a set number. Egg shells vary in porosity. So transpiration of moisture and gasses will vary from egg to egg but mostly constant between species, breeds and strains.
What you are trying to achieve is a weight loss throughout incubation of about 14% depending on species and that can occur early, middle or late in incubation or throughout.

 

[Mellowmalt]

does it have any vent to close ventilation holes? It sounds like the fan is sucking cold air in from the outside to cool things when it overheats. But this will lower humidity lots.
You need ventilation holes but you shouldn't be losing all your humidity when the fan kicks in.

 

[mmlaj]

I just found out it's due the fan. There is another big fan that is inside and should be on at all time to distribute humidity throughout. When I turn of this fan, it somehow heats up the incubator until it reaches above 38.2 C. This will entice the computer-fan-looking fan that will suck air from outside and the humidity will drop as a result. So by turning off the inside fan, the humidity is so much better now!

 

[Mellowmalt]

good to hear. It sounds like a fairly advanced incubator with an additional safety fan so it will most likely have lots of settings for alarms, humidity, temperature turning times etc. so check the values are correct.