Freezer Displays

Makes and models?

Is it possible that different symbols are displayed for target temp and actual temp, particularly if the latter was above the maximum limit at any time?

If you require and old manual I've often found sites such as:

my first suggestion would be to find yourself a decent thermometer

I have one of these

It works well giving the temperature in my fridge and in my freezer (two separate units) - it also gives max and min temperatures since the unit was cleared/reset.

Note alkaline batteries are only specified down to -20C and I found them unreliable when fitted to the wireless sensor in the freezer. Totally cured when fitted with 1.5V Lithium cells which are specified down to -40C

I have the same unit and it is both good and cheap. Recommended. However the instructions are in "Chinglish".

I don't get problems using ordinary alkaline cells and they will last 6 months or more.

Thanks for that.

I had been looking for this type of device, and had concluded that the two main drawbacks would be a) Alkaline batteries at the limit of their low temperature range - and b) sensors sitting inside a metal box (the fridge or Freezer) being able to transmit to a display unit some distance away.

Lithium batteries solve that first point, whilst the second point will have to be 'suck it and see'.

I'll risk £13 on that device & also get some Lithium AA cells.

P.S. I note the seller has the following suggestions:

"Do not put the receiver near metal" and "The thermometer's digital display is magnet-mountable on a fridge"

I have two sets of these (four senders and two displays) as I wanted to monitor the temperature display from two locations. I use each transmitter sender in a different freezer running at about -17 or -18C.

With alkalines after many months, both senders transmit reliably through the freezer door(s) and then through two brick walls to a reciever 40 feet away with no problem. They have worked for years.

Chinese manufacturers copy one another, so I don't know if what I have is precisely the same as what's on sale now. Or whether another vendor has an equally good product. I bought both in 2018 and they are still on Amazon:

The only annoyance is pairing each sender, especially using the crummy instructions I got.

I have the display mounted around 1 metre away from freezer. The fridge which is also being monitored is in an adjacent room separated by a brick and tiled wall

I've bought a bunch of rechargable lithium 1.5V AAA and AAs to replace aging NiCads, branded EBL and Photolex. They are quite pricey, about £2 each, but so far so good except for a couple of the AAAs - they only charge to about 1.3V. May well send those back at some point. And of course 1.5V - overcomes the issue of low voltage NiCads when pretty much everything needs multiples of

Yes, I noticed that. And I'm surprised they transmit through a fridge/freezer.

I just use a digital room thermometer, leaving it in for about an hour and switching it to display the minimum temperature after taking it out. Then I put it in the freezer section and repeat.

I wonder if my PI Pico W based boards would make it through the metal...the kitchen wifi point is only 3' away

I saw someone who'd produced a unit which attached externally by magnets to the freezer, and had a flat-flex cable to the thermocouple inside the freezer, hooked to home assistant I think

He was selling them in "amateur JLCPCB" quantities, but not cheap as he seemed to be clawing-back the costs of numerous prototypes over a short run of devices ...

I run two coin-cell based min/max LCD thermomreters, one in the fride, the other inn the freezer, over the course of 10 months the freezer has required one battery replacement, fridge not so far ... you never know how s*it the supplied battery is to start with.

I think most of the commercial (Amazon/ebay/Ali/etc) temperature monitors with an external probe use an NTC thermistor on the probe (typically 10K at some Beta value). So wouldn't be hard just to cut the probe cable and splice in a flat flex cable for passing through the door seal.

Or just measure the sensor characteristics and solder your own micro thermistor to the end of the flex cable - measure resistance of the original sensor at three temperatures and putting them into the Steinhart-Hart model gets you resistance and beta so you can source your own replacement:

Theo

In our case, both the freezers I want to monitor are in a utility room with a 22 inch thick rubble stone wall between that and the kitchen.

I would _like_ to have the display in the kitchen, since we spend far more time there and would thus notice an alarm or rising temperature.

Having the display in the utility room would still have value, but it isn't ideal (but then, what is?).

The cheap remote sensors mentioned in this thread operate at 433M

It's a great shame that there isn't a standard that all fridges/freezers use, to display actual temperature at all times (so you can see if the temperature is rising when it shouldn't), with the target temperature displayed briefly when you press a button. And that display to be visible at all times.

We have a Panasonic fridge and a freezer (separate units) which do just that. Our Beko freezers (rated for below-freezing outdoor ambient temperatures for a garage) all display the target temperature with no way of seeing the actual, apart from a crude "temperature is above some unstated level" light. One of them displays all the time, but the other has its display hidden by the top do the door and the display goes out when the door is closed. Even the "power is on" light is hidden.

We lost a lot of food from that hidden display freezer because the wall switch got accidentally turned off (a crate fell against the switch). It is possible that we may have noticed the absence of a power-on light as we were passing the freezer in the following days. Very poor design for a freezer if you can't tell at all times whether its power is on.

The other freezers are monitored by Kasa/Tapo smart plugs which monitor power usage over time and report it to an app on my Raspberry Pi, but we hadn't got round to setting up one of those for the Beko that got turned off.

With so many modern devices like washing machines and driers being monitored by internet these days, that ought to be a standard for all devices - so you can see the usage graph (continuous usage suggests door open or coolant leaked away [which happened on a brand new freezer which was replaced under warranty]; no usage recorded suggests power failure of freezer.

That freezer is jinxed. The first one lost its coolant, as I said. Its replacement lost power when one of our ring mains tripped for an unknown reason (never happened before or since) while we were away on holiday, and then last week the switch got turned off.

Agreed. I don't mind them always displaying the target reading - as long as you can get an actual reading at the touch of a button. Maximum temp reached during a power off/door open episode would be useful.>

Our small freezer has an LED display, but it's impossible to read since the back light is off unless and until you open the door (and hard to see even then). On more than one occasion the "Superfreeze" button has been accidentally pressed, and the only way we discovered this was finding the ice cream becomes incredibly hard @ -30C.>

Our new(ish) washing machine is WiFi enabled, and they expect you to run it from an 'App' on your phone. WiFi does not penetrate the super-thick stone walls to that room, and I refuse to install a wireless access point just for a $%^&* washing machine.>

Our large, high efficiency freezer has a habit of freezing up (it is supposed to self-defrost) around once every year or so. We have to empty and manually defrost the thing. This is a true PITA since it holds a lot of food and so it takes ages to run the contents down.

Mine never does that and doesn't self defrost, it just pumps frigid air in and you never get any frost inside the freezer.