Burping Update

GallenH · 07-10-2018, 04:22 PM

In reference to older thread re poor cooling Dometic 2310 3-way. Ok I pulled the fridge. Pretty easy really (only a 3cf so it's small). Spent a few days with it in the garage burping. Also cleaned coils, etc. with air and water. Disconnected 110v heating element and did a resistance test (passed) and connected the heating element directly to AC bypassing the thermostat (Dometic recommendation). Two days later it's only gotten down to 40 deg. and I'm wondering what's acceptable given the conditions. Those conditions are a garage where during those 2 days the temp ranged from the mid 90s (at night) to over 110 (in day....hey it's Phoenix). Should I expect it to get down into the 30s? Or is that unrealistic? I'm planning on giving it another day before I jump into any buy/repair mode. Ideas? Opinions? ......all welcome! Thanks.

GallenH · 07-10-2018, 04:28 PM

I meant to add that I've been monitoring the temps of the coils and boiler area with an IR gun. They appear to be relatively consistent from one to the other area....but....some times the overall temps appear to be higher than others. For example, readings might be c.116 on coils/boiler and, say, 8 hours later only 104 deg. Can't figure that one out. There is no thermostat controlling anything....the 2 wires of the heating unit go directly to AC power and nowhere else. Hmm.

hbn7hj · 07-10-2018, 04:52 PM

Perhaps the ARP website could give you more info.

https://www.arprv.com/

The first line on their website says boiler temp should be around 350F.

I doubt you are measuring boiler temp as you can't get to it, certainly not with an IR gun as you cannot see it. The temp you quote is correct for the bottom of the coils.

I find the website difficult to get the information one wants but it is all there, just have to browse around and read things about 20 times.

You should see freezer temps below 30F but probably around 50F for the box. I live in Phoenix (Tempe) but won't be back to help you out till October. It is hot there as you have noticed!
Harry

peteco · 07-10-2018, 05:33 PM

What is the freezer temp? Should be in 0 - 10 degree range.

Also, try blowing air across the rear coils, especially the upper condenser coil.

The ARPRV site is very good. I use one of their fans mounted on the exhaust vent to suck air up through the coils. I also have their controller to run the fans and protect the fridge.

I also did some vent mods to match the Dometic installation guidelines, which Roadtrek did not follow on my 2006 210P.

All of this has the fridge working OK, not great, but acceptable. I can achieve 39-41 degrees in hot weather (90's). I try to only put room temperature items in at night.

When this fridge fails I will likely put in a compressor fridge, though I will need a battery system upgrade also.

GallenH · 07-10-2018, 05:55 PM

Right: the IR gun only measures the outside of the insulation pack around the boiler. I was following a Dometic tech guide that said to start the fridge and hand check the coil and insulation pack temps after 2 hours. If one was hot and the other cold it indicated a particular type of problem. Temps on the pipe coming out of the top of the insulation pack are more in the 200-250 range.

GallenH · 07-10-2018, 05:57 PM

When I check temp at noon I'll put the thermo in the freezer, wait an hour and see what it reads. Not quite as hot today but very muggy. Monsoon rain last night so we're only expecting a muggy 102 today.

Doneworking · 07-10-2018, 07:41 PM

Under the conditions you reported in the garage, I would think 40 degrees would be fine. Like mentioned, it will be interesting to see the temp in the freezer under the same conditions. Like Peteco suggested, put a fan to blow upwards on the coils and see if that changes anything in 24 hours.

Personally, just me, I would be happy as a pig in slop if the refrig showed 40F under the garage conditions you indicated, assuming the freezer was reading acceptable.

Do you have anything in the refrig or is it just trying to cool the air in there? I would put one of these in there and a half dozen cold cokes or beers out of the household refrig and check the temps in a day.
https://www.campingworld.com/fridgec...-on-off-switch

Paul

GallenH · 07-11-2018, 03:40 AM

Fridge held right at 40 today. I did put the thermo in the freezer and waited a few hours. It read 0....actually -1. I'm trying done's sixpack in the fridge and the internal fan (I have one). Will check tomorrow morning. Thanks for your advice.

Bud · 07-11-2018, 12:20 PM

Quote:

Originally Posted by GallenH

Fridge held right at 40 today. I did put the thermo in the freezer and waited a few hours. It read 0....actually -1. I'm trying done's sixpack in the fridge and the internal fan (I have one). Will check tomorrow morning. Thanks for your advice.

Hi GallenH,

I got to wondering what would happen if I actually got my absorption refer out of my B and into the garage. Well, until I read your last post. I would enjoy the sixpack looking at the refer, and then I would reach for my 12 Gage while clicking 'place order' for the new compressor refer.

Bud

InterBlog · 07-11-2018, 12:58 PM

Our garage in the greater Houston area routinely reaches the mid-90s in temperature. Both of our Dometic 2351s maintain temps in the 30s under those conditions. Depending on the weather, it can remain in the mid-90s for days or weeks at a time.

I'm guessing you are the OP from that other recent thread which talked about burping (I didn't verify). If not, then my two sentences above would make no sense. Recapping for other thread readers, my husband and I struggled with two propane fridges until we gave up and went with a Vitrifrigo. The two surplussed Dometics are getting put together in a wheeled cabinet as an off-grid garage unit (handy in hurricane country).

GallenH · 07-11-2018, 05:05 PM

Yup. It was me on the other thread. Burping did improve the situation. I could start out the morning at 40deg but by about 6pm I was in the 60s. This morning I was 36 and dead 0 in the freezer. Yesterday at 6pm I was 40 and dead 0. So I'm curious. You obviously went through 2 2351s which seem to be doing fine with temps in the 30s. Why did you out one and buy another and then out them both? What was the problem with them? It must not have been the cooling given your current temps. Hey, thanks for all the advice and comment.

Doneworking · 07-11-2018, 08:06 PM

Gallen, 36 !!! That's great!

Paul

InterBlog · 07-12-2018, 12:49 PM

Quote:

Originally Posted by GallenH

.... So I'm curious. You obviously went through 2 2351s which seem to be doing fine with temps in the 30s. Why did you out one and buy another and then out them both? What was the problem with them? It must not have been the cooling given your current temps. Hey, thanks for all the advice and comment.

It WAS the cooling. While the units were successively installed in our rig, each, in turn, reached the point where they would not get below 45 degrees.

The first one went, and we installed the second because at THAT time, it was prior to the installation of our lithium system and we couldn't run a compressor fridge (our OEM coach battery was under the Sprinter cab passenger seat so we could not expand in situ).

Then the second one also "failed". We ran extensive tests and countermeasures while it was still in the rig, but couldn't find a way around it. Took it out and installed a Vitrifrigo.

Almost a year later, on a whim we burped that second Dometic, and suddenly it was fine. At that point we retrieved the original "failed" Dometic which had been sitting in storage for two years, burped it, and like magic, it too was fine. Live and learn.

We then decided to optimize the original investment by building our "Dometic condo" as an off-grid garage refrigerator. We didn't already have a garage fridge and we really needed a spare, so here we are.

GallenH · 07-12-2018, 05:19 PM

That makes sense. Don't know why I didn't think of the fact that you might have issues on the road as a reason for the 2nd. The reason that I was/am curious is that I'm guessing the burp might help temorarily but eventually I will have to replace the unit. The 2351/2354 is Dometic's "sized" replacement. It bothers me that a new unit would have a cooling unit problem. Mine is 20+ years old so the thought that some coolant has leaked out or that solids have formed over that period of time is understandable. Do you think it's a case of not making them as well as they used to? I read through the information on your electrical installation that you gave me in an earlier post. Thanks. What's your total battery ahs?

Doneworking · 07-12-2018, 05:54 PM

I think the more you use the refrig the longer it will work and, like the generator, a seldom used refrigerator can gum up. I recall posts on a couple of other forums that suggested that the act of going down a rough road was good for these absorption refrigs because it literally shook 'em up a bit. Kind of a non inversion burp I guess and I have no idea as to the validity or lack thereof concerning those posts but they contain some truth. Long term setting can be a problem, that is for sure.

I always feel a chill when I read a for sale ad for a motorhome that shows a model many years old with few miles and a "brag" about "only (insert a low number) hours on the generator". I always figure that is grand or two right there. A sitting long term not used refrig could logically have some of the same problems.

Paul

GallenH · 07-12-2018, 10:27 PM

I hear you. My father-in-law bought the van but only drove it the first 5 years until his wife became ill. It sat, maybe seeing one trip over the next 12 or so. When he sold it to us I had a family shop go over the mechanicals. Told them: think that it's your van and you're driving it from Wis to Az. Fix anything you would. Then to a RV guy who did the same with that stuff. New tires. $2-3k.
We knew that was coming. But he sold it to us for $1 after he decided that he had to stop driving. He was 98. RIP.

Picked up 2 decent cfm computer fans at an electronics store today and several 3' lengths of aluminum angle. In the process of figuring out mount strategy before I put the fridge back in. Mocking it up in the garage.

best.glenn

Doneworking · 07-12-2018, 10:34 PM

Great! I predict you will get many, many years of enjoyable travel from your B. Twelve years. WOW! It speaks to the integrity of the van and the quality of the build that it is in such a good condition.

I knew an elderly guy that had a small Class C back in the 80s and he had bad health and couldn't use it. He would go out and just fire it up and sit in it for a while, reminiscing the younger and better times.

After he died, his son told me he thought that little rig added years to his daddy's life. It gave him something to maybe, just maybe look forward to in the future.

Paul

GallenH · 07-13-2018, 03:58 AM

Thanks, Paul. My wife remembers her parents tooling around in it and it brings a tear to her eye. There's nostalgia in them there RV. Here's hoping that you're where it's cool.............I'm not until Glacier next month. Road trip!

best.glenn

InterBlog · 07-13-2018, 01:12 PM

Quote:

Originally Posted by GallenH

... I'm guessing the burp might help temporarily but eventually I will have to replace the unit. The 2351/2354 is Dometic's "sized" replacement. It bothers me that a new unit would have a cooling unit problem. ...Do you think it's a case of not making them as well as they used to? .... What's your total battery ahs?

I suspect it's more a function of the fridges needing burps on a regular basis (every 1 to 2 years per our direct and repeated experience) simply due to their design parameters, rather than it being a quality issue per se. Neither of our Dometics has actually "stopped working" even though the original is now 12 years old.

I don't know what is causing this phenomenon - someone suggested an obstruction building over time that can then be freed by burping. Whatever it is, clearly I can flip a garage fridge upside down far more easily than a van fridge, especially if that van fridge is propane which means it that is physically sealed IN the van so that products of combustion will not enter the living space. To get a van propane fridge unstuck, flipped, re-inserted and then (the big one) properly re-sealed is a huge P.I.T.A.

We have a 300 AH lithium battery. My husband is a mechanical engineer and he did the head work on sizing, although part of it was dictated by the available space. We did not want to consume storage space with any portion of our electrical system - we do not have an EXT Sprinter so we can't afford to waste what little storage space we have. So the battery with its cells configured had to fit under our closet floor. You can see the butt edge of it in this diagram below.

That battery was sized to run my computer system off-grid, and to run our microwave oven, long before we considered getting a Danfoss-based fridge. Other people have larger batteries, but I've never felt limited by our configuration - within reason, I have all the power I need off grid. Within reason - we obviously can't run the roof a/c around the clock, but nobody can no matter what their off-grid system looks like.

GallenH · 07-13-2018, 04:31 PM

The fact that you went with a compressor fridge makes perfect sense. I'd probably opt for one right now if I had an electrical system already in place as you did. And I can see why one would go through the hefty expense of upgrading the electrical system if you were going to be living in the camper for extended periods of time. Good choices.

Your Dometic(s) must be different than mine re sealing. Mine has "sealing strips" (look pretty much like foam insulation) that are fastened/glued to the flange on the top and 2 sides. The bottom was sealed with what looks like clear silicone caulking. Since this RV was in the family, I know that the fridge was never removed/replaced, so that had to be the way PW originally built it. Any sealing advice/tricks that you might have would be appreciated.

Hope that you're out of the Texas heat!

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