Walk-in freezer door

[Trio]

First post here, so a little background on me. I am 29 years old and have been in the hvac-r industry since I was 15(summers). I have always been more on the refrigeration side than the hvac side, but do both. I have searched for answers to my problem, but nothing pops out at me. I have a 2 year old walk-in freezer that the box was put up by a restaurant equipment installer, and we installed the refrigeration. It has recently come to my attention that the door absolutely will not open for at least a minute after it is closed. This caused major panic in one of the workers as she felt trapped. The detective work I did makes me believe this has been going on since day 1. So, I found the heated vent to be working properly and free of ice. When you close the door, the air just screams through the vent. I tried shutting down the refrigeration system and the same problem occured. I tried opening an outside door to relieve building pressure, same problem. Could it be the heated vent is just too small? The box is a Master-Bilt approx 12x8 with 9' ceiling and only has a 2'' vent. Any ideas?

[Warren]

The best thing to do would be to call Master Bilt, and they should be able to help you. You want to CYA in case anybody gets trapped inside nobody will be able to say the factory was not made aware of this problem. Just make sure that you get the name of person you talk with.

[wicked251]

You need a heated air vent above the door. This allows the air pressure to equalize, and the door to open.

[Tommy knocker]

Does your vent have 2 heated flaps? If so make sure they are both working. If one is bad it will stick and fool ya. You hear it vent and show amp draw but only half the vent operating delaying the process for a minut. Had this issue a few years back at a high school. Don't remember brand but something you might check. I replaced vent and problem gone. Good luck.

[Trio]

The vent does not have any flaps. A call to Master bilt found that it is a Kason 1825 series. They told us to install a larger vent, on the customer's dime of course. Just not quite satisfied with that answer. I've never run across this in the hundreds of walk-in freezers we've installed.
I see on kason's site, it is supposed to have springless valves. Off to check it out further.

[Tommy knocker]

Bummer!! Well it's not working, obviously, and it's the only thing involved. Swap it out. Never took one of those apart so not familure with the guts of it. Door probably not wanting to close either.

[icemeister]

The vent does not have any flaps. A call to Master bilt found that it is a Kason 1825 series. They told us to install a larger vent, on the customer's dime of course. Just not quite satisfied with that answer. I've never run across this in the hundreds of walk-in freezers we've installed.
I see on kason's site, it is supposed to have springless valves. Off to check it out further.

Your box is only 864 cu ft in volume. A single Kason 1825 Ventillator should handle up to a 3000 cu ft freezer. Check out the .pdf file attached.

1825 Ventillator.pdf

From this info and what you have described here, I'd say the outlet relief valve is stuck. It may be repairable, but replacing it with another 1825 is all that's needed. You certainly don't need a larger one.

Give Kason a call and relate your problem to them.