Defrost cycle Searle Evaporator

[Contactor]

This evaporator is serving a cold store approx 5mx5m full of frozen plane food, set point is -22C. Electric defrost.

How often do you reckon it should be defrosting? Previously it was at 8 hours, now changed to every 4 hours but still not enough.

Iceberg formation in process, temperature creeping up!!

Help!

[chillin out]

Every 6 hours.
Min time 30 minutes.
Max time 45 minutes.
Temp termination 12 degC. (defrost probe positioned in a good place)
Drip time 2 minutes.
Fan start -8 degC.

Set like this it will never ice up again. Nor will you have big frozen droplets on the roof.

Make sure you heaters are in the correct place.


Chillin

[Latte]

Contactor,

I would say that if a defrost every 4 hours is not enough then you have another problem.

Start with the basics, Is the door being kept shut or is the site in and out all the time, if the later are there any door strips on it or an air blower above the door ?

now assuming the door is being kept shut, Is the unit getting enough defrost, are all the heaters working, is the drain heater working and the drain line clear.
How is the defrost controllled, Is in on time/ termination temp or both (Is it on an eliwell/lae etc) . Is the termination probe (Probe 2) in the right place or getting a poor reading.

Any info on the set up you can give would be a help, its one of these difficult ones to try and diagnose on the end of a PC but i hope something here may help and if you can post the other settings we should be able to sort it

Regards

Raymond

[Mauro]

hi will be that valvula of expansion this very opened? , the people entran with much frequencia?

[lana]

Hi Contactor,

Check what rdocwra said.

In my opinion defrost time and duration has no general rules and it depends on the application.
If door is opened too many times and the outside air is moist then the defrost time would be different.
In blast freezers where fresh fish is being frozen (generally on the ships) then after half an hour the whole coil will be frosted up and needs defrost. You see it depends on application and also the product being stored.

You have to estimate the time and duration of defrost by experiment for each application.

Good luck
Cheers