Freezer door left open alarm

[Harry Bloomfield]

Working fine. This one -

I was confused about the range of the settings for these things, because none of them suggested that their alarm systems were capable of being set to negative/ below zero values.

This one can display the temperature where the display is installed (in) or that of the remote (out) wired sensor. An alarm can only be set for the 'out' sensor, an high alarm and/or a low temperature alarm can be set. Rear of display is fitted with magnets, so it can be stuck to the side of a fridge or freezer.

I have it set to alarm if the temperature in the upright freezer rises higher than 13.5C, which is located in the utility. Low alarm set to minimum, high alarm set to 13.5C. It triggers within seconds, if the door is opened, but restricts itself to a few bleeps every minute as a warning - it is just audible in the kitchen. I will eventually move the display through the wall, into the kitchen, to make it more audible.

The freezer already had a high temperature alarm, but just a light and not easy to spot unless you went in the freezer. I could have rigged up a simple door open alarm, but that would only trigger with the door open - this alarm will trigger if the door is open too long, or the freezer fails, or power is lost.

[Chris Hogg]

On rare occasions I have left our (upright) freezer door not fully closed. I doubt that it got significantly less cold inside, and the compressor probably worked hard, but when I came to open it the following day, it was a mass of icicles and frozen condensate, requiring a total defrost to clear it.

[Harry Bloomfield]

It happens that Chris Hogg formulated :

As was mine, which is why I decided a solution was called for..

[Chris Hogg]

In which case a simple temperature sensor might not register the problem if the temperature doesn't rise far enough. Perhaps a microswitch on the door, connected to a time-delay system, allowing you a few minutes access to the freezer before the alarm goes off?

[Harry Bloomfield]

Chris Hogg was thinking very hard :

As said, it works fine, responding quickly to the door being opened. It generally shows minus 17.5 to 18.5C, alarm set to trigger at higher than minus 13.5C. Left open for a full minute, the alarm sounds, but easy to ignore if you wish to, because it only sounds once per minute.

[Bill Wright]

Do you mean minus 13.5C?

Bill

[Harry Bloomfield]

Bill Wright expressed precisely :

Sorry, yes minus 13.5C

[Brian Gaff]

why not just use the door to control a switch like they do for the fridge light, never did understand why a few pence on such a device was not on all freezers. Cue Tommy Steel, i Puts the Lightie On on deca. Brian

[Harry Bloomfield]

Brian Gaff formulated the question :

It already has a built in 'temperature too high' warning light, but when lit it is not obvious unless you look at it with the door open and when you are in the utility room. I wanted an audible means of knowing when in the kitchen, that the door was left open or the temperature in the freezer went to high. So this serves to warn if the door has been left open, power has been lost, or the freezer has suffered some other failure.

[billj]

Mine didn't, just quite a bit of black mould on the inside of the door, easy enough to get rid of.