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 Post subject: Re: 110 Volt Fridge
PostPosted: August 16th, 2017, 6:54 pm 
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Well, it's got to be something (or somethings), and it sounds like you have the determination to get to the bottom of it. IMO, the fan shouldn't really be the thing that does all the cooling. Yeah, sometimes you can't do any better, but a good chimney will beat any fan (not that you'd get rid of the fan). That said, boats almost never get a chimney and they do okay (but too, they usually have a pretty small "box," and it's often got 4+" of insulation, with a small lid in the top only).

When I took my original refrigerator out, the generator compartment proved to be a tin box (nicely made), with carpet and carpet pad for "insulation." But that's really weak compared to what you can do with modern products that are meant for sound and heat insulation. I want to say there was over an inch of space there (maybe closer to two) to work with, once the carpet/insulation are off. They pulled off pretty easily, and then just a bit more work to get the adhesive residue off. You probably have already noticed this, but the rear 1/4 of so of the box is in the closet. Yeah, generator heat right under the refrigerator.... not the BEST plan. But when you're putting ten pounds of flour into a five pound sack, compromises must be made (and they did a good job, from that point of view). I'm always impressed at how balanced my rig is side-to-side, when I weigh at scales where I can check that.

On my rig, just as a data point, I have never seen any water come in the upper chimney vent (and it's open to a cupboard at the moment, so I'd notice). So it's quite a bit more leak resistant than the lower vent (ahem).

And yes, I agree, zero ºF is not unobtainable. My buddy with the Vitrifrigo DP150 is a total ice cream hoarder, and it's completely rock-hard frozen 99% of the time (as you may know, ice cream is one of the hardest things to keep frozen). And I don't think he ever had it turned all the way up. Plus we were in 100+º temps for a few weeks (although at that point we were plugged in and he was running AC, but still, it was darned hot outside and the refrigerator was on the west-facing wall). It's slightly smaller (I think 5.x cubic feet), but then too, it only has the BD35 compressor vs. your BD50.

We did put a huge amount of insulation all around it (since it is a fair bit smaller than the ol' Dometic absorption fridge). BUT, that said, he didn't want to keep the chimney, so the cooling path was not the absolute best (lower vent only, septum to divide incoming air from outgoing air, auxilliary computer fan hooked up to run when compressor running (and no way for heat to get trapped above the vent area).

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 Post subject: Re: 110 Volt Fridge
PostPosted: August 17th, 2017, 3:14 pm 
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Location: Santa Cruz, CA
Hey Blue - I took a flashlight and a mirror and tried to look up the chimney and I couldn't see any light above so I'm worried that the installer blocked off the chimney. Will get up on a ladder and pull the fridge roof vent this weekend to make sure its open. They also pulled up any carpet or whatever was under the original fridge so I will lay down some Dynamat and then Styrofoam to provide a buffer against any generator heat. Also, the DP2600 is shorter than the Dometic it replaced so I'll be raising the unit up about 3 inches so I can have a good deal of insulation underneath - probably using some 2 x 4's on edge secured to the generator box. I had 2 supplemental fans for my Dometic so I'll definitely put at least one on this unit.

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 Post subject: Re: 110 Volt Fridge
PostPosted: August 18th, 2017, 10:02 pm 
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Well that would explain a few things (if the chimney is blocked).

I continually forget what year your rig is (maybe you could put it in your signature or profile so it would show up in each post automatically?), but I can tell you how mine was originally.

For starters, the main coach floor is plywood. The generator sits partly under the floor, partly over the floor. There is a sheet metal box that fills that space. But no weight was on top of that box. Instead, there was a 1/2" plywood board that went from the stove wall to the closet wall, and the refrigerator sat on that. There was no insulation on top of or under the board, except for the carpet padding and carpet that was on the sides and top of the sheet metal box (not very effective).

There were bits of the vinyl covered 1/8" wall paneling (like is on the kitchen walls) cut to fit between the closet and stove walls, and the "slopes outward at the bottom" side walls of the Chinook. These were stapled and caulked in place -- because an absorption fridge guts and chimney is supposed to be completely sealed from the interior and otherwise there would have been gaps.

I can definitely see light coming from the open roof vent. In fact it was like a skylight when I didn't have it blocked off. I can't remember though how it looked from looking up through the lower outside vent, but I would imagine you could see some light.

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 Post subject: Re: 110 Volt Fridge
PostPosted: August 20th, 2017, 12:13 pm 
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Hey Blue - can't see any light but then the back of the fridge seems to come all the way back to outside wall. Still need to pull the roof vent to see if my service center sealed it off. Most of their work is good but like any service you get these days the level of attention to detail seems to vary.

All this is discouraging but I'm not giving up on it. Probably will use ice chests if we go to the lake this coming weekend but I have quite the collection of them from my pre-Chinook days.

Paul

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 Post subject: Re: 110 Volt Fridge
PostPosted: August 20th, 2017, 2:32 pm 
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Well hmm...

The original "cavity" that Dometic specified (which was accurate to my Chinook as well) was 24" deep. The Vitrifrigo DP2600 (which is what you have, IIRC) calls for a 23-11/16" cavity. So that tells me there is not much room behind it. (OTOH, it's 8.1 cubic feet as compared to the 6 cubic feet of the Dometic RM 3663 that was in my Concourse and likely yours.)

If I were installing that refrigerator, and I planned to use the original chimney, I'd probably either order the surface flange (door sticks out into room beyond flange, like the Dometic did), or place the flush flange (which I'm going to guess you have) on a trim ring. It looks like the clearance for the copper line in back is already 1-3/16" (in other words, 99% of the back of the fridge is 1-3/16" less than that max spec). I'd have to go back and look, but with chimney applications on "big" units I think Vitrifrigo specifies around 4" (yes, 110mm). You don't want it to be too deep or the draft will be less (plus it'll just take up extra space into the hallway). And maybe it could be a bit less because in the application they show it's exhausting back into the room, and a true chimney is "stronger," draft-wise, I'd think.

So maybe I'd use a 3/4" trim ring (you could use, say, 1 x 2 or 1 x 3 wood) under the flange to give you more chimney. Given that the original Dometic must have stuck into the hallway but a good 3" or so, you'd still be thinner. Or I might have gone for a fridge closer in capacity to the original, which would then be smaller (as you can see by the specs, you get around 30% more capacity for given outside dimensions with compressor vs. absorption - no "pachinko machine" in back taking up capacity). With the larger refrigerator, you have the combination of a larger compressor cooling a larger space, plus less insulation. BUT, that said, everyone chooses differently, and if a larger refrigerator is the choice, then you just have to accommodate it (which I'm not saying you didn't do - just laying out some thoughts).

Now what I said above.... I'd have to actually SEE it before deciding. Specs and drawings are great (and Vitrifrigos seem very accurate), but (at least for me), three dimensions is real. For my Vitrifrigo C130, one of my goals was to get it as close to the outside wall as reasonably possible (because the real goal was a wider passageway), so I made a cardboard mockup to see how I could best accomplish it, plus accommodate as much insulation is possible. But that's probably not something most installers would do, because most customers are not going to be thrilled with a monster labor estimate - they have to be quicker. That's probably the main reason I like to do my own projects. It's not that I really PREFER doing that to relaxing with a cold beverage, but more just that I can take my time, noodle things, and then know how they're done. But everyone doesn't have the same feelings about it (sometimes I envy those who can just drive in, drop their rig off, have the work done, then pick it up - so easy!).

Anyway, I seem to have drifted into a tangent. Ahem. So, presuming you had the RM3663, your "box" is probably 24" deep. Also presuming you have the flush flange model of DP2600 (door is flush with flange is flush with "wall"), then you don't have a huge amount of clearance at the back, and probably no added insulation (unless the 1-1/4" around the copper tube was just packed with insulation, but then there's no chimney). Some of the newer Vitrifrigos have a sort of "adjustable flange" (whereas they used to have flush or proud separate models).... maybe you have that and can adjust it outward?

No chimney isn't the end of the world, but the airflow has to be accounted for somehow (both cool air in, and hot air out). Numerous ways to do that --- and maybe that's not even the issue --- but I'd want to know what's going on back there. It's possible that excessive heat is accounting for the poor cooling, and the damage to some components, but it may not be. If the chimney was just left as-is, but blocked off at the top, you could have a big heat trap in there.

Vitrifrigo also do show just a lower vent, with a block just above it to make sure no heat goes up into the void. They show it on a smaller refrigerator, and it's maybe not ideal, but it's another option. My buddy who did this used the second fan that blows out from the tail end (while the original fan sucks in on the cold end). Then the chimney is just all insulation (also his DP150 is quite a bit shallower, albeit only like 5 cubic feet).

I hope this wasn't too repetitive or too much side-track musing (?).

BG

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 Post subject: Re: 110 Volt Fridge
PostPosted: August 21st, 2017, 10:26 am 
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Hi Blue - your input is always welcome. If the chimney is blocked that might explain why the freezer never really gets cold enough. I did have the same Dometic fridge as yours so all the dimensions should be good. Headed out to get up on a ladder to check the fridge roof vent today.

Paul

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 Post subject: Re: 110 Volt Fridge
PostPosted: August 21st, 2017, 10:55 am 
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Hey Blue - as you suspected there is almost no clearance at all between the back upper portion of the fridge and the exterior wall. I had my wife shine a light up the chimney from the outside access door and could barely see any light. There's a wiring harness of some sort running along the back of the unit that also partially blocks the chimney. So, they didn't seal the roof vent off but I will have to move the fridge back towards the interior to open up that chimney more. I also wanted to move the unit up so I could insulate under it so I may have to move the unit out more as I raise it higher. Don't know if I have an adjustable flange or not; Instruction manual is not very detailed and I didn't get the installation instructions back from my service center. However, I can see that I need more clearance at the top back of the unit to get the chimney functioning better. If we do go to the lake this weekend I'll leave the access panel off so any heat build up can escape through the side for now.

Thanks for all the help on this. I love this rig too much to give up on this.

Paul

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 Post subject: Re: 110 Volt Fridge
PostPosted: August 21st, 2017, 11:15 am 
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Good sleuthing!

BTW, that wiring bundle that runs across the chimney at about 18" below the inside overhead is the main DC wiring bundle that Chinook ran forward on that side. Mine had scary looking chafe/heat marks where it had apparently been riding on the fins of the absorption refrigerator, but luckily upon close inspection it was still okay. Glad I got those fins out though! Now it's encased in loom and not where it can chafe on anything.

On the Vitrifrigos I have seen, the "flush flange" is (as expected from the name) flush with the wall it's mounted on. And the door is flush with the flange and the wall. So all flat. The door handle(s) are little square chiclets that you slide upwards to unlatch the door. The "surface flange" (not sure that was offered in the DP2600) (and counterintuitively to the name, at least in my mind) has a door that stands proud of the wall it's mounted on. So the door protrudes into the hallway. Not sure what the handle looks like.

For the models that got the new "adjustable" flange (this came out in 2016 or so?), the handles you open the doors with are horizontal and shaped something like rounded staplers. On these models you can pull (adjust) the refrigerator in and out within its flange. Obviously this makes it so that two models aren't necessary. But not all the models come with this apparently. My buddy bought his DP150 after this change was made, but it still only came in "surface flange." On the other hand, my 130 was changed so if I bought it now it would have the adjustable flange style. That would have been handy for me as I would not have had to be as precise on the install framing dimensions.

Anyway.... back to your fridge. I can visualize what you're saying. Sounds like they simply put the refrigerator into the old hole and fastened it in place. You can do better, I think. And since you're going to have it out anyway (to do the generator box), then perfect timing.

I think I'd be deciding between keeping the chimney (and making it large enough to do the job), and using only the lower vent (then filling the chimney with insulation and blocking it off). My hunch is that the real chimney would do better since your refrigerator is large, and the compressor is the larger size as well. That will cut down on your insulation though.... so it's not totally cut-and-dried.

So (without looking at it of course), I would likely do one of two things.

1) Use something like 1x or thicker lumber (to match your rig's real wood type) to create a spacer frame that goes under the flange all the way around. That will instantly pull the refrigerator forward and give you more chimney.

2) Block off chimney on outside of roof, fill cavity with insulation board, and then optimize the lower vent but putting a septum between the two "halves" so that inbound cool air is kept separate from outbound warm air. Add a fan to the two terminals on the compressor that will make it come on whenever compressor is running. That would be on the outbound side, as (at least on the BD35) the existing fan is on the inbound side.

If the lower vent causes you a lot of leakage problems, then you could also consider a completely indoor venting scheme. You'd want air going in under the fridge, then up the backside, then out over the top. Obviously this adds heat to the rig in summer (but it adds heat in winter too, so could be good/bad depending on how you camp mostly.

Let me look up the specs on your DP2600 and then I can measure my rig to see how much you could more the refrigerator up. I can access the area where the overhead is lowered for the vent flat (on the roof) which you can't do with the refrigerator in place. I'll report back.

BG

Edited to add: Okay, looks like the DP2600 was always just a flush flange, and still is. So you can ignore that bit.

From the drawing, the body of your refrigerator (sans flanges) is about 53" tall. The distance (on my Concourse) from the top of the metal box that houses the generator (when it is bare metal with the carpet and padding removed) to the underside of the lowest part of the overhead (where the roof is indented/flat for the top chimney vent) is around 56" -- maybe a scoch more. The lowered area for the roof vent to sit on comes into the rig about 12", so from that point inward you'd be able to put quite a bit of insulation on top of the freezer. On the 56" section, obviously you'd be splitting that potential insulation area between the top of the generator box and the area above the freezer but below the chimney upper vent protrusion.

Widthwise, your refrigerator body is just under 23-1/2", so not much extra room. Of course, the original refrigerator also had no extra room for insulation, so you're no worse off, just no better. But you do have 30% more interior space in your refrigerator/freezer unit.

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 Post subject: Re: 110 Volt Fridge
PostPosted: August 23rd, 2017, 10:00 am 
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Hey Blue - Made my way up to Richmond, CA (two hour drive) to Swedish Marine, which had previously replaced my electronic control module. The main guy there found that the cooling fan for the coils wasn't hooked up correctly and was not running. Moved the connections to the right terminals and the fan still didn't come on. Removing the bad fan would have required removing the entire unit to get to all the fasteners so he installed a slightly more powerful fan on the outside of the coils. Within 15 minutes the freezer got down to 20 degrees and the fridge was at 40. This guy has installed and serviced Vitrifrigo for years and says they are pretty dependable. He called a distributor back east and was told that they have been dealing with a bad batch of cooling fans and have had to do many replacements. So, looks like this was not a normal thing for these units. He did caution me that under the best conditions the freezer will get down to around 12 degrees, which is good enough for ice and frozen foods but not ice cream. At my current weight (I'm thinking of becoming my own country soon) perhaps this is a good thing.

So, part of the problem solved. I'll still be moving the fridge back a bit into the hall so I can open up the chimney a little more and insulate under and around it, as well as lining the inside of the chimney with Dynamat so I can reduce the heat when that side is exposed to the sun. Checked the fridge this morning and at the #3 setting out of 5 the freezer was down to 15 degrees and the fridge was down to 34. Just clicked it up to #4 to see what that does. Its cool today outside and overcast so I'll have to wait for a hotter day to see if the new fan is going to keep the temps low.

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 Post subject: Re: 110 Volt Fridge
PostPosted: August 23rd, 2017, 10:29 am 
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That is great news! I mean, not that they had a bad batch of fans, but that you know what the main issue was. I wonder if excessive heat from this issue contributed to the failed control module as well.

I don't know specifically about the DP2600/BD50, but my bud's DP150 with BD35 kept ice cream hard as a rock. He kept a thermometer on the fridge and freezer (with remote display) and IIRC the freezer was typically at around 7ºF (and I don't think the control module was maxed - that likely would have caused the refrigerator to freeze, since I think it's a spill-over system.

Annoyingly, this guy is not the size of a new country (ha!), because he always has at least 5 pints of premium ice cream "in stock" (and the stock DOES rotate). There's no justice, clearly :evil:

I think your plan to re-install the fridge is a good one. You'll be able to set the height you want (insulation top vs. bottom), put in real insulation (hint: shag carpeting doesn't count :lol: ), and get the chimney going nicely. Granted, solid insulation in that area would be wonderful, and with a chimney you won't have room for that, but at least any heat that comes in on that wall should go up and out the chimney (and as you say, maybe you can put a thin layer, especially where the Chinook gets wider).

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