Refrigerator insulation

[Susan Ray]

My Alder Barbour reefer system seems to be working fine but the freezer unit has a thick, icey frost layer build up within 2-3 days of defrost. I have sealed the lid and no cold escapes there and I try not to open more than 4 times a day, and quickly. Has anyone put more insulation behind and alongside the refrigerator? What did you use? Did it help? Any ideas? Thanks

[Ron Hill]

Susan : Most of us cruisers have put all kinds of additional insulation around our fridge box!!! 
I sprayed foam on the starboard side between the hull and the box (carefull if you use the expanding foam not to force in the inside of the fridge wall.  You can also use NON expanding foam). 
Then I put 3 1/2" foil faced fiberglass batting around the port side of the box, front of the box and around the bottom of the box.  I covered that with 1/2" metallic bubble wrap on the outside of all of those sides and secured both with metallic duct tape. 
I added a piece of 1/2" foil faced Styrofoam to the seat back (in the salon) that is the front of the box.  It's behind the seat cushion and taped in place.
Added a piece of 1/4" foil faced building insulation to the side toward the stove.  Not much room there so that's about all I could do.
On the top of the lid is a 1" thermal pad that was made to fit the entire top.
Every little bit more of insulation helps!! BTW, we only open our lid a couple of time a day.  Beer/sodas/water are in a separate cooler.

Not to offend you, but this is about the 5 or 6th time that I've written this same thing up. 

[Susan Ray]

No offense taken and Thanks..I will go ahead and add everything you have suggested and then some and that should fix or at least help the problem. Mahalo.

[Ray & Sandy Erps]

There is a wealth of information on boat refrigeration at Richard Kollmann's website.  Insulation is one of the biggest factors affecting performance.

http://www.kollmann-marine.com/

[Craig Illman]

Susan - If you're getting excessive frost on the evaporator, it's likely from humidity, not the lack of insulation (in my opinion). I'm sure you have the individual contents well sealed, so that they're not getting freeze-dried? Also, it sounded like you had a good seal around the lid? After being out for a couple weeks last month, we probably had less than a 1/4" or so build up. I still need to enhance my insulation around the box and possible build an interior divider.

Craig

[Ken Juul]

I think Craig is on the right track.  The moisture has to come from somewhere to form the ice.  Check that the holes where the freon lines enter the box are sealed.  I don't know how the box is sealed to the counter top, but that seems like it could be a big source of humid air if there is a gap.

The extra insulation is also a good idea after you solve the air leak.

[Susan Ray]

This morning it is 76 degrees with 70% humidity...maybe that has something to do with the freezer build-up....  I have very little access to the exterior of ice-box as the PO mounted the compressor on a platform 2" from box front. I have been stuffing closed cell and other foam alongside in hopes that will help. The freon lines look sealed from inside. I put 2 strips of window insulation around lid of box inside. I put silicone caulk on inside rim below counter top. I may cut out behind settee cushion to access that side. That Kollman site is excellent. Thanks again to all, Susan

[tonywright]

You say "the PO mounted the compressor on a platform 2" from box front".

Hmm, wouldn't this mean that all of the heat extracted from the ice box is blowing right back around the outside of it from 2" away?   You might want to look at having the compressor relocated well away from the ice box so that it is not fighting itself...If it is running a lot in order to try and get the temperature down, this could lead to excessive ice build-up.

On a standard MK II the compressor is all the way back in a stern locker, with lots of space around it for heat dissipation.

On the topic of improving refrigeration performance and reducing the need to run the compressor: for an overnight trip out I use large camping style freezer packs from our deep freeze and fill the freezer box with these. I run the fridge for 24 hours before departure (plugged into shorepower), and then only run the fridge while the engine is running (the way charter companies ask you to do it). This way everything stays plenty cold, and the batteries never experience a drain from the fridge. Of course you don't get ice for your drinks, but we don't put ice in our beer or wine anyway...The cocktail set might not like our solution, but so far it works well for us.

Tony