the maoster:
Ok, a few genuine questions here, I’m NOT taking the ■■■■■
I’ve been on fridges a few years now and apparently like many others received no official training prior to being let loose. Why is it a bad thing to do a forced manual defrost? My thoughts have been that when I do one lots of water exits the fridge via the drains, I assumed that getting that water out would be a good thing? Obviously I’m open to being persuaded otherwise.
Also we do lots of multi drop work where I’m not on a bay but rather unloading in a yard with a pallet truck. In these circumstances I always switch the fridge off because all it seems that I’m achieving is creating ice on the floor etc. Am I correct in doing that whilst the delivery takes place?
Lastly regarding ice, as mentioned we lots of off bay multi drop and certain fridges end up with a large build up of thick ice on the floor at the front. My way of dealing with that has always been after my last delivery to set the temp as hot as it will go and “cook” the ice for a few hours to clear it. It’s certainly effective but am I in any way damaging the fridge by doing that?
Probably newbie questions, but if you don’t ask you don’t learn.
Excellent questions, and let me explain what you are asking and I apologise now for the long replies but it is important and you have raised some very important points that I can clear up and hopefully educate a few others that may have the same questions.
On the point of initiating manual defrosts, as I have said, there is a time and a place for them no question about that. It is not to be done as some have suggested whilst loading or unloading. Lets assume a few scenarios here where it would not be good practice.
Firstly lets say as per your example of frozen. Most loading bays that deal in both fresh and frozen will try to maintain a bay temp of 4 to 5 degrees. You rock up to the loading bay with your doors open and position yourself on the bay. In the summer months as the weather is now you will have a lot of dry ice flowing out of your trailer and onto the loading bay. Good for the temp issues on the loading bay but when you have 8 or more wagons doing the same thing, loading bays can resemble a scene from a horror movie with vast clouds of dry ice laying layers over the floor. Your frozen produce has started loading onto your lorry and the forklifts are flying in and out of your trailer. You will see the dry ice now swirling in and out of the back of the box. You now pop your box into defrost and the fans stop running. now more than ever you are getting more dry ice into your trailer as there is no positive blowing so this dry ice settles onto the floor and walls of your trailer. the temp warms up from the defrost and causes the dry ice to form water vapour which is now saturating the trailer. When the defrost cycle ends and you’re unit starts to pull down, your coils will be wet which is why the fans should have a delay whilst the liquid refrigerant is pumping around the coils to freeze this moisture before the fans kick in. because of the high moisture content now introduced into your trailer through the defrost cycle, you’re trailer will freeze this moisture making even more ice than you originally would have including the floor area. More chance of icing up the evap coils as well as any air vents much quicker. This is the original senario that someone commented on here as suggested doing. It would be much more beneficial to have defrosted the trailer before loading or if really necessary to leave the manual defrost until your load is fully loaded and the doors are shut and left for aprox an hour for the temp to stabalise. Then a manual defrost will do the least damage as far as your load temps and forming ice around the evap coils and chutes.
As for your query regards delivering multi drops and switching off your fridge unit whilst the doors are open, this is exactly the recommended procedure, also good practice whilst loading too for that matter.
You’re other point of after you’re last drop is to cook the ice and clear the unit is also a good practice, rather than a defrost by turning up the heat you will clear the ice and drains etc much better. The condenser coils in this instance can be a problem but depending on weather conditions will not be a real issue. The main thing to remember is NOT to initiate a defrost whilst loading frozen, also to keep the doors open to a minimum, when the doors are open, stop the fridge unit and start it up when the doors are closed. Keeping defrosts to a minimum is the key. Hope this helps and clears up any confusions regards manual defrosts. Leave defrosts to the auto pre programmed cycles and do what you’re doing now and you will have very little problems.
