I was called to look at a recently installed walk in freezer the other day due to it regularly breaking down.

The interior light was wired on the same circuit as the compressor and every time the bulb popped it threw the rccd breaker with a loss of stock. Any way, the door has been built without any threshold just a rubber draught strip on the bottom of the door and frost is everywhere on the inside as you can imagine.

A couple of data loggers were put in to try and see what was happening to temps and humidity but I put the wrong temp logger in there - I used an insertion probe logger without the probe - doh!! anyway I have now put both loggers back in for a set of new data.

From the results of the humidity data it would appear that lowest %rh was about 80 and the highest was about 95%!!

What would you expect the RH to be in a decent -18C freezer?