Hova-Bator 1602n and temp issues

My husband bought a hova-bator 1602n second hand, and left it to me to try and figure out. It came with no instructions or manual, and I don't even know if all of the pieces are there. I've got the incubator, the water tray and piece of mesh for the bottom. The lid has the thermostat (no fan, but I believe this model doesn't come with a fan). It also came with an egg turner. My research tells me that there should be some red vent plugs in the top that aren't here....idk what else may be missing.

So.....sigh. It's been plugged in for about 24 hours now. It's in a sturdy, safe place with a pretty consistent room temperature and out of drafts. The humidity in the room is about 40%, and I think that if I can get the temperature to settle the humidity will be somewhat easy to control. The temperature is KILLING me though. I'm hoping someone might have some tricks or tips for getting this model to work....or can tell me if we got shafted in buying it used.

It heats up just fine....better than fine in fact. This morning it was over 110* degrees in it. I turned the little knob thing on top to lower the temp, and when I checked it two hours later the light was off, and the temp was 80*. So I turned it back up, slowly, until the light turned back on, then left it. An hour later, 105*. Adjusting it down, and the light goes off. So I did the on/off/on/off thing a few times until I hit the 'sweet spot' - the lowest I could turn it but still have the light on. Checked it, about 102*....checked again, back to 105*. Turned it down, light went off. And so on.

I'm ready to drop kick the ****** thing out the ****** window.

Help? Anyone? I kept a dozen eggs out of the fridge when I collected yesterday, and they're on the kitchen table, waiting to go in. However, I have no intentions of putting anything in until I can get the temp stable for at least 24 hours. Anyone want to help a newbie to the incubator? So far, easier to just let my girls do it, lol!

I think that is the same model as mine. Once I figured out the temp, it stays 99 to 100. Just keep adjusting. Mine has an add on fan.

I have the same incubator without egg turners. Are the egg turners in it now? Try taking them out. I have exerienced extreme tempature swings only when there is not enough air flow. I now keep 25 eggs in maximum and the tempature stays stable when they are the only things in it and they are spread around nicely. But I never had swings that extreme, maybe like 10 degrees as an absolute max. You may have gotten a bad incubator. I have hatched without vent plugs before just fine, and then of course found them again while that batch was hatching, hahaha. But I usually get 95% hatch rates by hand turning with this incubator so it's not a bad model. Keep playing with it and when you think you've finally got it, wait 2 days to make sure. Eggs are still at their max a week later and I have hatched even older eggs so there isn't a big rush.

You could also purchase a fan to help keep it more steady, they sell them separately for about $30.

First of all here' a link to the instructions https://www.gqfmfg.com/pdf/Thermal Hova-Bator instructions.pdf

In a used incubator like that there is no way of knowing how old the wafer is and It may need replacing. You might find a replacement at a local feed store or you can order them numerous places on line.
The pilot light goes on and off with the heating element as it is cycled by the thermostat, on when heating, off when resting.
Working with you have now make sure that the wafer is snug on the bottom of the adjusting screw. If it is loose it will give you all kinds of grief trying to get it dialed in. Then keep doing what you have been doing, turning it down a little at a time till you have it holding at the temperature you want. The attached instructions call for 100 degrees measured at the top of the eggs. You should probably do this with the turner in place and plugged in, because the turner motor adds its own heat and you don't want to have to readjust to accommodate it later. When you do get it where you want and it holds more or less steady for 24 hours you can put the eggs in. When you do the temperature is going to drop and take quite some time to recover. Do not readjust the thermostat to try to get the temp back up. It will return to your preadjusted temp once the mass of the eggs has been warmed all the way through.
While a fan is nice millions of chicks have been hatched in still air incubators . Personally I wouldn't bother adding one at this time.
As for the missing vent plugs, anything will work, a coin, a marble, tape. You get the idea.

Thank you!! I'd found that (or one very close) link in my searching, but kept getting a bad page message - this one worked! I read through it and tightened up the wafers, and it looks as though it's settling down. The woman he bought it from said she'd used it three times, and it's really in great condition. Last check it was about 99* - the lowest it's been without being off - and I'm quite hopeful that a few small tweaks will have me where I need to be. Which will be nice, because my broody last hatched about a month ago, and I'm ready for some more babies!

Well, we played with the darn thing for days, and the temp was either 110 or room temp (75). I was getting frustrated, so my hubby took the whole thing apart and decided we needed to just replace the guts and try with that...he also fashioned some vent plugs out of those foam ear plugs. So we ordered a new wafer and a new switch. He started by just replacing the wafer, and that did the trick - within an hour we were sitting steady at 101, it was clicking on and off like it's supposed to, and the humidity was spot on. After 24 hours with not one adjustment needed, last night we put 22 eggs in. Anticipating it would work correctly off the bat, I'd held a dozen eggs out to set....put that dozen in just to see what they'd do because they were 10 days old yesterday. Also added 10 fresh eggs from yesterday. So now we'll see what we see in three weeks.

Oh, and I also have a brand new switch if anyone is in need of one.

I bought one that was supposedly only used once and had the same issues. I bought a new wafer and added a cheapo fan. For the fan, you can get a $5.00 computer fan and power it with an old cell phone charger. I used a very small one that just lays on the mesh pointed up towards the lid. Cheap fix.

Hi I have the same problem with the temp;,( what I think is a problem ) I can set the light to come on at 37.5, but during the night it will go down to 36.6 before going back up, then during the day it will go up to 38.4 before going back down. I have only used the machine once before and it has no fan. I have 8 eggs now it is the 6 day, are you saying it will run better if I add more no fertile eggs to make to number up

I know this is an old(ish) thread, but I have to chime in. I have a Brinsea Octagon 20 Advance that's been my primary incubator. I added a Hova-Bator 1602N recently as a hatcher so I could have the flexibility to stagger hatches and to keep my primary incubator cleaner. From the get-go, the HB 1602N was a ridiculous hassle to try to keep the temperature steady in. It would wildly swing from too low to too high with even minor adjustments. I think the fluctuations were definitely a factor in the unusually low hatch rate I had for the duck eggs I put in the HB 1602N at lockdown. After that, I promptly returned the HB 1602N (it was lucky to still be in one piece at that point!) and bought a HB 1588 to use as an incubator and hatcher - it performs as expected, unlike the 1602N.