frig issues

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faraway
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Joined: Jun 29th, '07, 11:52
Location: cd30b Faraway jax Fl

frig issues

Post by faraway »

I installed a cold plate system on my CD30B and now I have a little sweating around top opening.
How could I go about stoping this??????
Boyd
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Joined: May 9th, '05, 10:23
Location: CD 30 MkII

lid sweating?

Post by Boyd »

Your problem sounds like project creep.

I just installed a new Fridgoboat system in my boat and had extensive sweating issues. After all I live in the humidity capital of America. Project creep.

If the sweating is at the door gasket then your goal is to stop the flow of warm air from above the counter coming into the fridge and the cold traveling out the bottom. This little loop of circulation is usually through the bottom drain. First thing to try is to plug the drain in a manner so that its completely air tight. Removing the drain entirely is an option worth thinking about.

The second strategy is to improve the door gasket. Reducing the flow of hot air to close to zero is the goal. I used a readily available EDPM foam window gasket that comes in rolls from HD. Tightly fitted and glued in place.

My problem was a bit more extensive. See if any of this sounds familiar.

The original lid seal is a single 90 degree ledge made of teak with some bogus foam gasket that the lid sat on. This "seal" let a lot of hot air into the fridge and condensation formed at the interface of the hot and cold air, namely the lid "seal".

The second issue was the counter around the lid would get cold enough to form condensation. The top of the fridge it turned out was nothing more than the 3/4" plywood counter. Surprise no insulation on the top of the fridge.

My fix is pretty extensive and while I love detail and complexity may not be for everyone.

I fabricated insulation panels out of urethane foam with 1/8" plexiglass for the inner liner. These are attached to the underside of the counter with long screws and silicone caulk. This was in conjunction with panels that are added to the underside of the lid increasing its thickness to over 2".

I fabricated a new angled lid gasket that extended down to cover the edge of the new panels and gave me the opportunity to make a second seal for the lid.

While my insulation is now nothing like the 4" all around that new production refrigerators have, its a dramatic improvement. The 24 hour amp-hr usage has dropped from 54 to 28. Part of that is due to the higher efficiency of the Fridgoboat unit and part due to the extra insulation and better gasket seals. In fact the insulation was good enough that the Frigoboat unit would not cool the fridge to 40 degrees. Yes that seems backwards but having a well insulated box can cause the compressor to short cycling. The fix was a small circulation fan.

By the way Fridgoboat customer support is great. There is a LOT more to this story but I wont drag it out, hope this helps.

Boyd
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Cathy Monaghan
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Icebox insulation

Post by Cathy Monaghan »

Hi faraway,

Though we don't have refrigeration, we do alot of cruising so keeping the ice frozen in the icebox for as long as possible is important.

One of this year's project was to improve the insulation at the top of the box. CLICK HERE (or on the photo below) to see some of what was done to the icebox aboard our CD32. What we did is somewhat similar to what Boyd describes.

<center><a href="http://s4.photobucket.com/albums/y117/C ... ley/"><img width="540" src="http://i4.photobucket.com/albums/y117/C ... a></center>

The original lid is a bifold made of teak plywood, covered in laminate (Formica) and filled with a small amount of foam, the whole thing only about 1 inch thick. The old gasket was pretty useless so the plan was to increase the amount of insulation for the lid, insulated the top of the box and replace the gasket.

We purchased a 4'x8' sheet (1 inch thick) of polyisocyanurate foam, that was covered in a plasticized foil, at Home Depot as well as a sheet of LEXAN and a new gasket. We also used silicone caulk and long screws and finish washers for attachment.

For the lid I cut 2 pieces of foam, each with a 1/4" bevel (see the photos), wrapped the edges in white duct tape then wrapped each piece in clear vinyl which was secured on the side that would be up against the bottom of the lid (the top of the foam).

Two pieces of LEXAN were cut to fit the dimensions of the foam then I drilled 4 holes, 1 at each corner, through the LEXAN and the foam into the bottom of the old lid.

With everything disassembled, I ran a bead of silicone caulk around the edges of the lid, around and in each screw hole then placed the covered foam over the lid. Then I ran a bead of caulk around the edge of the covered foam, in and around the screw holes and placed the LEXAN on top of that. It was all then screwed in place with the long screws and finish washers. Because the LEXAN is transparent, you can see the clear silicone caulk between it and the covered foam. I probably should have painted the topside of the LEXAN (the side against the foam) white so that it wouldn't be noticeable, but it works the way it is.

For the underside of the top of the icebox, my husband used the same polyisocyanurate foam. First he made a template from cardboard then he cut the foam. Anyway, use essentially the same process as for the lid. It's not the most permanent of solutions, but it works.

The gasket was glued to the lip around the hatch opening.


Cathy
CD32 Realization, #3
Rahway, NJ
Raritan Bay
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Steve Laume
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Post by Steve Laume »

Insulating the ice box is on my project list. I picked up a book on improving your ice box last winter. What they stress and had not occurred to me is that the top of the box is not where you need to expend your efforts. It makes sese when you think about it. The cold doesn't rise up out of the box. Heat doesn't sink in either. a good seal around the lid makes good sense but the lower areas of the bos are the most important parts to be well insulated.

I have a good way of dealing with the drain. I took a hole saw and made some inch and a half plugs out of closed cell foam. The plugs are about as thick as they are round. I push one in the drain and it is insulated but stll has a tiny hole from the pilot drill in the middle. It is mostly squished shut from shoving the plug in.

Frozen milk jugs start us out. Then the ice goes in a dry bag. It will be great to get more insulation in the box.

Refrigeration???

Bilge beer works for me, Steve.
Boyd
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Location: CD 30 MkII

Physics 101

Post by Boyd »

Heat moves by 3 mechanisism, conduction, convection, radiation. Of these, two are independent of gravity or orientation, in other words heat moves by these two modes in any direction equally. Convection is the only one that depends on gravity and is the mechanism that a poor lid/drain seal allows to work.

Heat transfer by conduction and radiation is the same in all directions. Radiation is not a a likely mechanism of heat transfer in this situation unless you have a glass lid.

The main mode by which heat enters a well sealed refrigeration box is by conduction. The rate of heat transfer is a function of the R values of the materials, the area, and the temperature difference from inside to outside of the box. The idea that the most effort should be concentrated on the bottom of the box may arise from the fact that most boxes exhibit some stratefication since most dont have circulating fans. Cold air does tend to sink to the bottom and the top will tend to be a bit warmer. This is why manufacturers recommend placing the evaporator as high in the box as possible. The temperature difference from the cold bottom to the warmer top is probably not more than 20 degrees so the difference in heat gain of a square foot of bottom vs top is not that great. This combined with the fact that most boat refrigerators are wedge shaped being small at the bottom and wide at the top means the heat gain from the top in total BTU's from the top is actually greater than at the bottom.

The top of the box can be a significant heat gain. I think the idea that the most effort should be concentrated in the bottom is wrong and the entire box should be insulated to as close to the same as possible.

Boyd
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Zeida
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Post by Zeida »

On Bandolera I have exactly the same condensation problem on my ice box. The countertop around it is always wet.

I have a Frigoboat unit that works wonderfully, but the gasket on which the lid sits, is extremely worn out, barely 1/4" thick. By reading you all's postings, maybe I will get my courage up and try to do something about it other than putting towels all around the ice box. My box also has the bottom drain hole. It would be easy enough to get a plug and keep the small hole closed, but how do you insulate the bottom of the ice box? Or the entire box, for that matter?

By looking at Cathy's fabulous reconfiguration of the lid (mine is the same) I could possibly try and do something similar. My question is: right now, the lid closes just even with the rest of the counter. But remember it sits on a worn out gasket. If I replace the gasket with a new one, the lid will not close properly. how are you guys dealing with this?

I do keep the A/C on my boat (at the slip) on at all times, plus two small fans circulating the cool air. When the temperature inside the boat is about a steady 79-80 degrees, there is no condensation from the Frigo. Only when it gets hotter inside!
Zeida
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Cathy Monaghan
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gasket for lid

Post by Cathy Monaghan »

Hi Zeida,

zeida wrote:".....My question is: right now, the lid closes just even with the rest of the counter. But remember it sits on a worn out gasket. If I replace the gasket with a new one, the lid will not close properly. how are you guys dealing with this?....."
The old gasket on Realization's icebox lid was also worn out and useless. From what we could tell (and it was hard to tell because it was so corroded), there had been gasket material on both the lip of the hatch opening and on the lid since there were remains of gasket on both but it may only have been on one surface. Anyway, your old worn out gasket is probably no where near as thick as it used to be.

There are many different sizes and shapes of gaskets. We purchased one from Home Depot. It is shaped like half-round moulding and is hollow so it is compressed by the lid. The box of gasketing material is down on the boat. If I can remember, I'll let you know exactly what I used once I get a hold of that box.


Cathy
Boyd
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Pictures

Post by Boyd »

If anyone is interested in seeing my gasket/lid combination send me a PM.

Boyd
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CD30 MkII
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Zeida
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Post by Zeida »

Hi, Cathy,

Thanks for the input on the frig lid. I went to home Depot and got two types of gasket (since it is not that much) one is the roundish one you describe, the other one is 1/4" flat. I'll see which one fits better. The gasket on my ice box is only on the lip of the hatch opening. There were no remnants of anything on the lid itself. I've needed to do this for the longest time, but other items got the priority.

I just finished replacing the tiny 2" outside diameter heat exchanger that came with the Universal 2454 Model 30 engine, with the bigger, sturdier 3" o.d. and what a difference it is making! Now the temperature on Goldie is hovering between 175 and 180 degrees, which is what the manual says! It was A JOB! since I had to replace all the hoses that go to and from it. Also my brother welded an extra fitting on one end to get the hose pointing in the right direction, and everything is working fine!

The new Sendure Heat Exchangers cost $300. So I had been struggling with the overheating for all this time... until last year in Annapolis, Mitch Bober sold me (for $50) the one he bought from Mike Rit (La Vida) (for $75) which he finally did not use in his boat. I took it to a radiator shop and for $20 they refurbished the old kinks -it was very beat up- completely. I cleaned and cleaned the inside thoroughly and made sure it was still in good shape, which it was. So I primed it and painted it and with the new fitting, it turned out to be like new... Now I have a decent stream of water coming out the stern exhaust, and the engine is no longer overheating!

So dealing with the condensation in the icebox/frig, is the current project. And I would also love to convert all my lights to LED's but after reading all the posts on this subject, I may try to wait until they can come up with just a bulb that can replace the existing ones in the lamps that we all have, which are pretty standard everywhere... I am sure that at some point, that should happen.

Hope your summer trips are wonderful. I wish I could do a Harry Potter and fly Bando up there to join the Main flotilla. I will be looking forward to reading all the posts afterwards. Again, thanks.
Zeida
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Cathy Monaghan
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Rubber gasket

Post by Cathy Monaghan »

Here's the gasket info for what we used.

Frost King
X-TREME RUBBER WEATHERSEAL
Self Stick tape
3/8" wide 1/4" thick 17' long
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