Making a walk in box

[bill8309]

I need a walk in box for crabs this coming summer. I have priced new and used box's and they are costly. Has anyone made or know how to make a walk in box from a shed, using a window a/c unit and a cold bot for a thermostat. Let me know if it works or is it a waste of time.

[Hunterjjd]

window shakers will not cool enough

[jack1747]

I think a window unit would dry the air to much...

[Mikie]

I've had one for over 20 years and it works fine. Once or twice when the outside temps were in the upper 90's the unit iced up, but other then that it's been great. Mine's 6' x 8' with a 5,000 btu unit, and I run it between 44*-46*. I don't let the air blow directly on the baskets and if I'm keeping the same crabs in there for more then 2 days I'll throw a couple of wet towels over them to retain the moisture. My a/c unit has the old, mechanical controls. All I did was adjust the limit screws on the thermostat to lower the temperature range. With the newer, electronic controls you would probably have to buy one of those control boxes. A neat little tip - buy an indoor/outdoor thermometer and mount it on the OUTSIDE with the probe running through the wall into the unit - read the inside temp without opening the door!
It's also handy if you kill a deer in bow season while the temps are warm.

[Mr. Breeze]

We keep our crabs at 48 to 52 F.  Depending on the btus of the unit, and the insulation in the box, a windos unit should suffice.  Good idea about the themometor outsie the box

[horsefly]

you can generally get used refrigeration equip from auctions  IE; grocery store closing for renovations w/e. Sometimes you can get panels and units little to nothing....except must require moving and hookup.
Built a small cooler out of cinderblock 8' x 12' used this powderer type block insulation to fill holes. Used the largest 220 window ac to cool 50 bu of crabs. It worked hard when ambient temps were in 90's but to help......dip bushels of crabs in ice water for 30 sec to pull core temp down. Or....go old school and use ice on floor about 6 inch thick in a well insulated building should last about 3 days +  Just need to keep them 45 to 52 degrees

[Mr. Ray III]

A new a/c unit won't get cold enough.  Or at least the one I had did not.  It got down to about 60* and did pretty good.  I had a bucket of water to try to keep it humid, and I kept towels on the baskets.

[Mikie]

Window A/C units will only go as low as the range the thermostat is set for. You need to put a thermometer in the outflow air to see how cold the unit is capable of supplying. If it's blowing cold enough, you either have to adjust the thermostat below it's pre-set range or buy one of those "Cold Bot" things like they advertise on here.

[realcraw]

Did some research on CoolBot. They explain how the unit tricks the thermostat of a window unit to keep a well insulated room near refridge temp (although for crabs 48 - to 52 is fine as Mr. Breeze says). My buddy who does heating and air confirmed that with the right sized unit and proper insulation it should work in theory. Google Coolbot - they explain all details on their site.

[Mikie]

Window a/c's blow the same temp air the whole time the compressor is engaged (with slight variations based on the temp of the intake air supply). The thermostat senses the room temp and shuts off the compressor after the set temp is reached while leaving the circulator fan blowing. When the room temp warms back up a little, the thermostat clicks the compressor back on again. Most of the window a/c's I have checked have been capable of supplying air in the 35*-40* range. BUT, you have to bypass the pre-set thermostat RANGE to achieve these temps in the room being cooled.

[Mr. Ray III]

Mikie, I tried two different window units.  I couldn't get them below 58*.  I also called jimbob, on the other site for help.  He does HVAC for a living and he couldn't get me set up.

[Mikie]

Ray, you need to do what I said above. Get an auto a/c thermometer and stick it in the outflow duct on the unit. The temp coming out of the unit after it's running for awhile is what it's capable of supplying. If the air is cold enough (and it usually is) you have to CHANGE or BYPASS the thermostat on the a/c unit to the range you need. Window a/c unit thermostats are pre-set NOT to go below 60 some degrees. Older, mechanical thermostats could be adjusted by changing the upper and lower limit screws inside the thermostat. The newer electronic units, I don't know anything about. The "Cold Bot" controls will work with the newer units.

[flounderpounder]

Mikie, I tried two different window units.  I couldn't get them below 58*.  I also called jimbob, on the other site for help.  He does HVAC for a living and he couldn't get me set up.

what other site?    you mean theres more?

[muddyclaw]

YES a window shaker will work.... I have been using a shaker in a well insulated block shed and it will cool to 40 on the hottest days in the summer, I have a johnson controller hooked to the unit you have to unwire the fan,stat and compressor and hook the fan to run constant and hook the compressor to johnson controller and do away with the stock stat. I have read about the cool bot and its the same concept but you can only use new shakers so it might work better im thinking about getting one myself cause they say they can get down to the 30s

[bill8309]

Hey...Thanks for all the great info...I am going to build a shed and make part of it a cold box. Now I need to know is what to do with the floor...do I leave it pressure treated plywood or do I cover it with something. I am worried about the water soaking into the plywood. Let me know if you have any advice, Thanks

[baycrabber1]

been using a 10,000 btu window unit and cool bott for 5 years now in a 8x8 WELL insulated shed kep it at 42 deg.  no problems