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Refrigerator cooling solution "gelled"

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Does anyone know a way to return the cooling solution back to it's natural state after it has gelled? The temperature outside dropped to 14 below zero and the refrigerator stopped cooling, so I am pretty sure the solution gelled.  So what's the best procedure to fix this problem? 

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Welcome to the forum. Glad that you're here.

A little more information might help us offer suggestions. What type of refrigerator are you talking about (make/model)?

I'm assuming that the refrigerator is inside a heated RV and not outside in the -14 weather, so what makes you think that something has gelled?

If this is an LP fridge, have you checked all the necessary outside vents to be sure that they are clear of snow and that they haven't become blocked by freezing condensation in/on the vents?

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It is a Dometic RM 7732, gas/ac prod 921 14 80-03, ser# 54400088, yes, inside a heated RV.

All the vents are open and cleared.  It switches between gas and ac but does not cool. Everything was working perfectly until the temperature dropped... 

Lp works.  Good flame etc..

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How warm is it inside the rv? I don't believe an absorption type refer will work in freezing temps or at least not effectively. If the temp is -14 and the rv is outside, I can't imagine the inside is much about freezing, if that. 

 

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Shooting from the hip here, so hopefully someone with more experience with absorption refrigeration can confirm the theory...

These machines make cold by first making heat. Whether on LP or electric, they have to heat the refrigerant. That's why there are vents on the back of the unit, to vent the exhaust gases.

From reading a bit online, if the unit is well ventilated to accommodate summer use (the usual time these are used) there exists a possibility that the extreme cold outside air coming in the vents is keeping the unit from being able to produce enough heat to make the inside of the fridge cold.

Some solutions I'm reading about this are variants on a theme - warm the temps in the area behind the fridge. They include things like placing a light bulb behind the fridge to warm things a bit and/or to partially block the intake to help keep the temperature up back there. Both of these seem to me to have inherent safety issues, so I don't feel comfortable suggesting these as a solution to you. Hopefully others can chime in as the method of partially blocking the vent seems popular on other sites, and it would be nice to hear from someone that's actually implemented that as a solution.

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The RV was a balmy 65 degrees inside.  Everything I found says the refrigerator can take all kinds of cold if it is not running.  But if you run it in cold temperatures it loses efficiency and the solution can gell...  but I can't find what to do if this happens.  Will just applying heat to the coils fix the problem?  Today is the first time we have been above freezing.. also there was no mention in the manual that the refrigerator should not be operated in cold weather.

 

52 minutes ago, elkhartjim said:

How warm is it inside the rv? I don't believe an absorption type refer will work in freezing temps or at least not effectively. If the temp is -14 and the rv is outside, I can't imagine the inside is much about freezing, if that. 

 

 

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If my understanding is correct, it's not the temp of the coils inside the fridge that is the problem. The problem appears to be that the heating element cannot always overcome the extreme cold and heat the ammonia solution to make cold. I know it sounds weird, but if the system in the rear of the fridge cannot make heat, it cannot make cold.

The system at the rear of the fridge is pretty much isolated from the interior of the coach. This is largely done to prevent any exhaust gases from entering the interior as the system operates. Unfortunately, that means that all that balmy air inside your coach isn't going to help the backside of the fridge be warm enough to operate.

I've search through the manual for your unit that I could find, and it doesn't mention anything specific to winter operation. However, there are notes in the manual for another Dometic manual which specify a partial vent cover for use when outside temps fall below +8C (approx +45F). I can't find such a recommendation specifically for your model, however.

I did find one recommendation that mentioned parking the rig so that the side of the coach with the fridge gets as much sun exposure as possible. Guess that might help on sunny days.

Hopefully there are a few absorption fridge experts out there with more specific advice?

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We had the same model in our last coach and ran it as cold as 10 degrees outside and never e experienced this situation. I will say since I saw this post and doing some research it’s not uncommon. Some models have a cold weather package that was an option from what I have read. Of course there was no description of what this package consisted of.

If it were me I’d reach out to Dometic and ask them. In the meantime I’d shut it down and move the food to a cooler outside. I wouldn’t recommend altering the unit without consulting the manufacturer.

Dometic customer support;

 

686C7AC5-8614-4CC5-8A02-EB75C2A35C32.png

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17 minutes ago, jleamont said:

...If it were me I’d reach out to Dometic and ask them. In the meantime I’d shut it down and move the food to a cooler outside. I wouldn’t recommend altering the unit without consulting the manufacturer...

Sounds like good advice. Good news is that with the cold temps there is no worry about food going bad.

Friend of mine had an apartment in Paris - it was in an old district, and his 'winter fridge' was a cabinet with a back side that opened to the outside air with nothing but a screen to keep food from falling out. Maybe you have a basement bay that is at about the right temp where you can store food to accomplish the same thing till you get a definitive answer from Dometic.

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Thanks everyone for you help...  Here is the response I received from Dometic...

"Unfortunately, Dometic does not have a consumer technical support department. Authorized service centers and/or dealers provide all technical support. They are trained and certified on Dometic products to be able to assist you. They will trouble shoot, diagnose your unit, and contact Dometic to obtain authorization to provide warrantable repairs if applicable.  It’s possible the solution in the cooling “gelled” because of the frigid temps.  This is something that should be looked at and diagnosed by a qualified service center for confirmation.  If that is the case, the cooling unit would need to be replaced."

Not that I do not trust their advise, but this is a sealed unit and nothing has changed except the solution has "gelled". Without replacing the cooling unit there should be a way to return the cooling solution back to its natural state...  Does anyone know what that process might be?  I am certain that I am not the first person to have this problem... was the cooling unit replaced every time this happened? Will it just go back when the temperature warms, or can I put heat on the cooling unit and make that happen.  I have put indirect heat behind the refrigerator... but the refrigerator will not cool on A/C or Gas operation...

 

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The only reason absorption refrigerators have a chimney behind them is to exhaust excess heat. Keeping that in mind, this is the usual remedy for your problem. First make sure the insulation surrounding the heating elements fully-encloses the heat tube/LP gas chimney.

The solution to this issue is to block off the bottom outside vent (incoming air), or place a trouble light below the cooling unit as necessary to allow sufficient heat build-up to  boil the solution so it turns into a gaseous state. Refrigerator cooling will not occur until that happens. Absorption cooling unit explained

 

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Place a trouble light with a 40-60 watt bulb in the outside rear of the refrigerator and close off some (23rd) of the compartment vents.  

This is not the first I have heard of this happening and it has happened to me.

Lenp

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27 minutes ago, DJSafariCoach said:

I have put indirect heat behind the refrigerator

What are you using for indirect heat? You might find this helpful. 

https://www.youtube.com/watch?v=WyJuSbfo8Aw

You might try more or less tape over the vents. See if you have vents at the top.

I would probably try a hair dryer to speed up the warming being careful to make it a fairly even heat.

Bill

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If they don't provide technical support, then it's unlikely the person you spoke to would know whether or not the unit needs to be replaced. To me it seems unlikely that exposure to cold could damage the unit, otherwise there would be warnings all over the thing to not store it outside in the winter. Since we know that they are routinely stored outside in sub-zero temps in the north, without any damage, I'm going to go out on a limb and predict that once you get the thing warmed up it should start to work again. Might need to reset the power to it once you warm it up, but that's easy.

There are lots of good threads out there on other sites. Just do a Google search on "Dometic LP fridge winter problem" and you'll find them.

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Very good thought Richard. It may get crowded out on that limb because I agree with you and I"m sure a lot more do to. Do you think a 60 watt bulb could put off enough heat for that cold of temperature? Maybe if it was put on when it was above freezing it may have helped. It was suggested to cover the vents on the cover. Would the unit get enough fresh air from the roof vent to function properly?

I have been in subzero weather before and the antifreeze would gel but not freeze solid and would return to complete liquid when the vehicle reached temperature.

If it were me, the first chance I got I would pack it in and head as for south as I could. I would go far enough that the folks there would ask"Whats a Parka". then stop.:lol::P

Herman

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28 minutes ago, hermanmullins said:

I would go far enough that the folks there would ask"Whats a Parka". then stop.

Herman, What's a Parka?:rolleyes: I like that one. Since there are turns and bends and an orifice involved in the process, it is possible that that the gell is blocking the normal flow of the system. locating the orifice would be my starting point for applying some warm air, this point should be the area just before the freeze plates in the unit, and with that in mind, the hair dryer heat forced at the plates would be my starting point. Hope this helps.

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Before residential fridge in a coach, I had Dometic.  Even in Texas it gets cold enough where the unit would work erratically!  We would unload the unit and turn it off.  Then when we headed out again, during winter it was always, deep South Texas.  We would turn on Fridge, when ambient temps reached 50F.  Never had a problem!  The only unit that gave me fits, was one 1200 NorCold and I only had it for a year, 2007!  

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As I said, i block the bottom intake vent, works every time for me and many others. Anyway,  The Norcold Guy says the same thing except he uses the upper vent, with a caution to remember to remove the blockage from the upper vent because it cannot be seen from the ground. He does have a disclaimer for that reason, avoid liability if an owner fails to remove the upper vent blockage when warm weather arrives.

As to "gell blocking flow"; the only way that happens is when the owner operates their absorption refrigerator out-of-level enough times to create the blockage. A side effect of cold weather RVing is, the ice maker water supply line and water valve may freeze if the heater wire that's taped to it is not working. The above solution also remedies the ice maker water supply issue.

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1 hour ago, RayIN said:

As to "gell blocking flow"; the only way that happens is when the owner operates their absorption refrigerator out-of-level enough times to create the blockage.

How do I clear the "gell blocking flow"?  I sealed off the back of the fridge and pumped hot air behind it for 12 hours.... I am trying to start it on gas because I can hear and see the flame igniting, but it is still not cooling. The fridge is level, the bubble is dead center.  Any ideas?

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Just a guess here, but have you shut the power (12v and 120v) to the fridge for a few minutes? That might let the circuits reset and thing might work after you turn the power back on. Works wonders on some devices. Does nothing on others. Cost nothing to try.

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You have a source of heat, salt water and Ammonia.  The problem is, it will only work in an environment above "0" F.  Your "gel" is actually, slush water, they use salt water, because it has a much lower freeze point, than fresh!

In a Dometic Fridge, built in  the late 90's, level is 6 degrees front to back and 3 side to side, not critical anymore, as it was in the 60's, 70's, 80's and early-mid 90's!

Unless your living in your RV, I would do as Kay suggested...turn the unit off and wait until early spring or until your out of Parka weather, if your going South!

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13 hours ago, DJSafariCoach said:

How do I clear the "gell blocking flow"?  I sealed off the back of the fridge and pumped hot air behind it for 12 hours.... I am trying to start it on gas because I can hear and see the flame igniting, but it is still not cooling. The fridge is level, the bubble is dead center.  Any ideas?

This is a normal flow diagram of an absorption refrigerator:  image.png.7e646253da05f16671fe50a9f517f2f3.png

 Unless you have repeatedly operated your frig outside its operating limits, you will not experience what some refer to as gelling/plugging. It is cumulative; this is what happens when the frig is repeatedly ran outside those limits:" Continued operation in an over-heated condition results in cooling unit blockage whereby the rust inhibitor becomes crystallized and blocks sections of the internal tubing in the boiler. Unfortunately, this process cannot be reversed." This quote copied from The RV Doctor website

BTW,  I doubt the above is your problem. The picture explains what happens when the frig is level, when out-of-level you can visualize why the unit over-heats.(flow is stopped/inhibited)

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DJ.

Go on web and look up Absorption Refrigerator...it will give you the history all the way back to 1878 to present time.  Dometic from 1907, Electrolux.  Various types of Vapor, gas, liquids, etc.  Including the history of when Dometic, at the time part of Electrolux, came out with AR for the trailer and then MH industries.  A rolling, bouncing, twisting earthquake going down the road and the AF still is functional.  

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