polar 2 door upright freezer

[Andy AC]

Went out to one of these lovely cabinets today, which had recently turned in to frosty the snowman inside, all over the walls and ceiling. Switched it to manual defrost, which it did for about 10 seconds before going back to cooling again. Thought that was a bit odd, as the evap fans didn't stop either. Anyway, had a look at the controller and found that it only had 1 relay for the compressor, no defrost or fan relays, also only had one probe (T stat). Wiring diagram only shows one probe and also no sign of defrost heaters, heaters for the door frames but that's it. The machine is about 8 months old, never had any thing done to it, I was just wondering why it has taken this long to be come a problem, or am I missing something?
I would have changed the controller if I had one, but as there was a general lack of wiring/probes didn't seem like much point. Told the customer to speak to those extremely unhelpful people at Nisbets for a service call - good luck to him.

Anybody had the misfortune to have been called to one of these?

Andy

[G Cook]

If its the kind of cabinet I'm thinking of (pipes in the walls) then I'm sure they are a manual defrost freezer, just like a chest freezer. There is no defrost period set in the controller, it just acts as a thermostat.

[Andy AC]

That would explain things

Andy

[Grizzly]

Hi Andy.
I have loaded what I think may help you onto mediafire.
Follow the link below.
If this is the correct type the parameters D9,10,12,13& 14 will be of interest
Sadly the pages are to big to load up to the forum.

From what G Cook has said it may be the case that there is not a defrost.
But have a look all the same.

I think you will find they control the defrost through a Compressor off function.
Grizzly

http://www.mediafire.com/?w44upf6q9c7u54f

[Grizzly]

Just to add. See below.

The REK31E and REK31ED controllers are electronic instruments, designed and manufactured to measure, display, and control temperatures between – 45
... + 95 °C, and can control timed defrost cycles through compressor OFF. It is particularly suitable for applications in positive temperature refrigeration
plants. The thermostats can control a compressor, with an absorption of up to 8 A, directly through a relay.
The compressor is activated when the temperature rises and reaches the set point + differential value and is stopped when the temperature drops back to the
set point value.
The thermostats can also control timed defrost cycles through compressor stop. Both the interval time between defrost cycles and the duration of the latter
can be set by the end-user.
The temperature is detected through a semiconductor PTC probe that can be installed up to 10 m / 30 ft from the thermostat without need for instrument recalibration.
The temperature detected by the probe(s) is visualized on a 2 ½-digit red LED display and two red LED horizontal bars. To indicate negative
temperature values only the central horizontal bar lights up, while both horizontal bars light up to indicate the instrument is in the parameter configuration
mode.
The instruments have one relay output for compressor control.

Grizzly

[Andy AC]

Thanks for that Grizzly, good info

Andy

[G Cook]

Surley a freezer cabinet cannot defrost without heat being introduced?