|
Some of these posts are very old and might contain outdated information. You may wish to search for newer posts instead.
|
MorePies
Stranger
Registered: 02/09/16
Posts: 808
Loc: TX
Last seen: 1 month, 1 day
|
How to Adjust the AA 75X's Thermostat 1
#24273886 - 04/26/17 05:04 PM (6 years, 8 months ago) |
|
|
If you are reading this, then perhaps you also have felt a pang of uncertainty and fear when trying to sterilize something in your AA75X. Twist as you might, the only increase in PSI you feel is your blood as it boils hotter and hotter. What happened?!? Did $900 worth of aluminum just turn into crock pot? Hopefully no and your heating element is fine. This guide will show you an adjustment to make if your AA75x is set to 10 and still not hot enough or set to 1 and blowing the 25psi valve.
On a side note. If you are in a pinch, these units can be run at full blast with the mechanical 25psi release functioning at no harm to the unit. The only danger is running the thing dry, which shouldn't happen given the standard practice sterilization times and being sure to properly fill the 75x before using.
Now onto the guide.
You will need:
-A flat head screwdriver -Needle nose Plyers -Loc-Tite Red AND NOT PICTURED HERE LOC-TITE GREEN The green is a penetrating seizing compound (think gets into the threads) The red is works more on the outside -I believe it's a 5/16 socket, but I'm just going to say a socket set to be safe.

1) These directions are for when the 75X won't get hot enough, which seems to happen more often. If your 75x is too hot, follow the directions and read the **note below. Prepare your 75X to do a sterilization run as you normally would AND position the 75X so that you have access to the panel underneath the controls.
2) You need to go through the whole process. Vent for 10 minutes, let it build pressure and temperature to where the element is turning off, or it's at your desired temperature/psi. So without further ado please turn on your 75X and while it is heating, remove the bottom panel.
3) Remove the 3 hex/flat head screws and the plate they were securing.

4) Removing that plate gives access to the nut that is on the shaft that connects to the thermostat dial (the black dial that you turn to point at 1-10). It's the nut that's next to the red dot in the picture. At this point, twist your thermostat control nob from 1-10 and watch what happens in there. That nut moves a plate (that some electrical engineer can explain how) that controls the temperature. What has happened is that the factory loc-tite like compound has failed, allowing the nut to spin and you not to be able to the temp you want. What we are going to do is re-calibrate the thermostat and once that is done, apply new loc-tite to hold it in place.

The 75x I had to repair is used on my mushroom farm. Since I won't be the only one to use this unit, I wanted to decrease the chance of operator error and make it so that when the dial is set to 10, it's at my desired psi and turning the element off at 20psi.
5) Now that your 75X has heated up to the point where it's turning the element off turn your knob to 10.
6) With the needle nose pliers, take hold of the nut so that it can not spin and then turn the control dial to 1. Release the nut.
7) Turn the control slowly the right to see where your new max psi is. If the shaft is turning, but the nut isn't that's more tricky. You would need to turn your dial to the desired number, hold it there and turn the nut clockwise to adjust the thermostat.
8) Repeat steps 6 and 7 as needed.
**If you have gone to far, or need to make your max psi less. Set your dial at 5, take hold of the nut and turn to the RIGHT to 10.
9) Adjust as needed until you find your sweet spot. Once found, follow the directions on the loc-tite to apply to the nut. Turn the 75x off, and let the loc-tite set overnight.
10) Put the plate and three screws back in, then the cover plate. Done and done.
Here is my re-calibrated unit. It's on, set to 10, and the element just ticked off.
|
TravelAgency
The ongoing "wow"


Registered: 12/25/10
Posts: 4,431
Last seen: 11 months, 21 days
|
Re: How to Adjust the AA 75X's Thermostat [Re: MorePies]
#24274108 - 04/26/17 06:19 PM (6 years, 8 months ago) |
|
|
Very cool MorePies- I don't even have one but with the way you described it I'm sure I'd be able to do it. Great write up!
|
drake89
Mushroom Magnate



Registered: 06/26/11
Posts: 4,168
Loc: TN
Last seen: 4 years, 10 months
|
Re: How to Adjust the AA 75X's Thermostat [Re: TravelAgency]
#24274149 - 04/26/17 06:35 PM (6 years, 8 months ago) |
|
|
You should always wear gloves and eye protection when working with live electrical equipment. Last time I was under the hood of one they did not have insulated chassis wiring connections.
|
MorePies
Stranger
Registered: 02/09/16
Posts: 808
Loc: TX
Last seen: 1 month, 1 day
|
Re: How to Adjust the AA 75X's Thermostat [Re: TravelAgency]
#24274224 - 04/26/17 07:16 PM (6 years, 8 months ago) |
|
|
Quote:
drake89 said: You should always wear gloves and eye protection when working with live electrical equipment. Last time I was under the hood of one they did not have insulated chassis wiring connections.
Great point!
Quote:
TravelAgency said: Very cool MorePies- I don't even have one but with the way you described it I'm sure I'd be able to do it. Great write up!
Thanks!
|
MycoFlora
Farmer


Registered: 10/06/14
Posts: 309
|
Re: How to Adjust the AA 75X's Thermostat [Re: MorePies]
#24293486 - 05/03/17 09:01 PM (6 years, 8 months ago) |
|
|
Thank you for posting this! I hope I'll never need it, but I am glad it is a here if I do. Youre the man thanks again!
|
drerock
Stranger
Registered: 04/03/14
Posts: 21
Last seen: 2 years, 3 months
|
Re: How to Adjust the AA 75X's Thermostat [Re: MycoFlora]
#24310910 - 05/10/17 09:35 PM (6 years, 8 months ago) |
|
|
I made a post about this as well. Except my instructions are reverse of yours.
I just calibrated my 75x thermoswitch this week and had to hold the nut with the knob at 5 , and turn it clockwise toward 10.
|
|