Just Browsing Fridge temperature issues ....Again

[Troy Foz]

Hi All,

once again I'm having fridge temp issues, I'm currently doing some fridge trails as I'm always weary of the temp in the fridge as I've had issues in the past.
I've got a 150 lt dometic 3 way in my 2005 Expanda Outback I have fitted an external fan to the back to increase air flow and have purchased a wireless thermometer to keep track of the temp.

I'm noticing overnight on the AC 240v it gets down low to 3 degrees but if you open the door once or twice for 5-10 seconds it jumps straight up to 5-6 degrees and stays there and yesterday whilst sitting in the workshop it went up to 12 degrees with no door opening or anything.

I've just moved it onto gas to trail for the day to see if i get the same fluctuation.
Any assistance would be great as its doing my head in and I'm off to the Kimberly in 1.5 weeks.....

 

[Drover]

If the fridge is empty yes it will do that..... House fridges will do the same if empty but no one checks them......all the cold falls out .

 

[Troy Foz]

If the fridge is empty yes it will do that..... House fridges will do the same if empty but no one checks them......all the cold falls out .

I have a logger in there at the moment to track the temp, have spoken to a caravan fridge bloke and he has mentioned that could be the thermostat as I just checked it now and its sitting at 13 degrees.

 

[Drover]

Have you gone over the connectors, I tidied up my thermostat probe and connectors but since I did other stuff as well I'm not sure of the effect but fridge worked better so left it alone but soon as the door is opened up it goes and takes ages to drop down.....the internal fan seems to work well with an even distribution of air........mines a 186lt job.
I drowned my wireless sender unit in the drip tray so just rely on the icecream test.

 

[Boots in Action]

Hi All,

once again I'm having fridge temp issues, I'm currently doing some fridge trails as I'm always weary of the temp in the fridge as I've had issues in the past.
I've got a 150 lt dometic 3 way in my 2005 Expanda Outback I have fitted an external fan to the back to increase air flow and have purchased a wireless thermometer to keep track of the temp.

I'm noticing overnight on the AC 240v it gets down low to 3 degrees but if you open the door once or twice for 5-10 seconds it jumps straight up to 5-6 degrees and stays there and yesterday whilst sitting in the workshop it went up to 12 degrees with no door opening or anything.

I've just moved it onto gas to trail for the day to see if i get the same fluctuation.
Any assistance would be great as its doing my head in and I'm off to the Kimberly in 1.5 weeks.....

Hi @Troy Foz , seeing as you have changed the supply from 240 volt to gas, you have changed the parameters somewhat. @Drover was correct when he said that empty fridges do lose all their coolness because there is only cold air in there, and being at the bottom, it is the first to vacate the fridge as the warmer air comes in at the top. If you have some items in there already cold, that coldness is retained especially if in the freezer section. Whereabouts do you have your sensor for the fridge? If you do not have any internal fan/s to move air around and the sensor is near the top or close to the evaporator, the coldest point will be on the bottom shelf. The warmest air will be at the top AWAY from the evaporator. Also what setting do you have on the thermostat for your fridge? Unless you have a late model fridge, the thermostat only controls the temp whilst on 240 volt. There is no temp control on the earlier fridges when they operate on gas, but later ones do have some sort of separate control. And yes, the heat absorption fridges ARE a lot slower to recover from warm items being placed inside or frequent door openings. Have a read of my latest post on "Form guide for my tortoise" and note how things should go. The fan at the back must be working well for the fridge to get down to 3 degrees overnight when the air is cooler too. Let me know if you need further info. Cheers

 

[Troy Foz]

Hi @Troy Foz , seeing as you have changed the supply from 240 volt to gas, you have changed the parameters somewhat. @Drover was correct when he said that empty fridges do lose all their coolness because there is only cold air in there, and being at the bottom, it is the first to vacate the fridge as the warmer air comes in at the top. If you have some items in there already cold, that coldness is retained especially if in the freezer section. Whereabouts do you have your sensor for the fridge? If you do not have any internal fan/s to move air around and the sensor is near the top or close to the evaporator, the coldest point will be on the bottom shelf. The warmest air will be at the top AWAY from the evaporator. Also what setting do you have on the thermostat for your fridge? Unless you have a late model fridge, the thermostat only controls the temp whilst on 240 volt. There is no temp control on the earlier fridges when they operate on gas, but later ones do have some sort of separate control. And yes, the heat absorption fridges ARE a lot slower to recover from warm items being placed inside or frequent door openings. Have a read of my latest post on "Form guide for my tortoise" and note how things should go. The fan at the back must be working well for the fridge to get down to 3 degrees overnight when the air is cooler too. Let me know if you need further info. Cheers

Hi @Boots in Action once again thanks for the Info, Ok so I've spoken to a fridge guy and have put a logger in the fridge for 48 hours to see whats happening in there. I've moved it back to 240v for a couple of days so we can track the temp but at the moment it is sitting at 15.8 degrees and the door hasnt been opened in 4-5 hours.
I understand that its empty but 15 degrees over a couple of hours isn't right I assume, the thermometer is sitting on the middle shelf and the fridge setting is on 5 with max being 8.
It was mentioned by the fridge mechanic that the thermostat might be no good but the data logger will tell us that. I'm heading out to the Kimberly in a couple of weeks so you can understand this isn't the right start.....bloody fridges.

 

[Boots in Action]

Hi @Boots in Action once again thanks for the Info, Ok so I've spoken to a fridge guy and have put a logger in the fridge for 48 hours to see whats happening in there. I've moved it back to 240v for a couple of days so we can track the temp but at the moment it is sitting at 15.8 degrees and the door hasnt been opened in 4-5 hours.
I understand that its empty but 15 degrees over a couple of hours isn't right I assume, the thermometer is sitting on the middle shelf and the fridge setting is on 5 with max being 8.
It was mentioned by the fridge mechanic that the thermostat might be no good but the data logger will tell us that. I'm heading out to the Kimberly in a couple of weeks so you can understand this isn't the right start.....bloody fridges.

It takes time to draw down temp inside @Troy Foz . And your ambient temps in Darwin would be high. If you have had a look at the chart I did for my fridge, you will see that at high ambient temps it does take some time and the freezer section takes absolute priority. Very little coldness is available to fridge section until the freezer has "had its fill" of liquid ammonia. Try turning the thermo switch back and forward a few times (min to max) just to free it up and make sure that contacts on thermo are contacting properly. Also try a higher setting, say 7, although this will not make it cool faster, but may drop the temp a bit lower. Diagram of operation of fridge is attached. Also, make sure that fridge is level and within the limitations of proper operation. As it got down to 3C before, I do not think it will be the thermostat. Other things like proper door sealing, proper air circulation of air at rear and position in sun (shade fridge side if possible) are more likely IMO.
Keep trying and good luck. I would be very interested in the final result., for my own info!

http://www.portablefridgesonline.com.au/how-3-way-fridges-work

 

[Troy Foz]

@Boots in Action Yes I've read your chart you have done some work there the rest of us are lucky, the van is under shade in a roofed section ill try turning the dial as you have mentioned and I noticed it also takes a while to draw down which it did through the night to 3 degrees but it has been on 240v for 4 days now and i noticed on your chart day 3 you were sitting around 2-3 degrees.

the freezer is very cold and i have some water in there that is frozen solid as well as some of the side walls.

I suppose the main objective is to keep food cold and not give the family food poisoning.

 

[Drover]

You do need to have something in the fridge to take up space, a few bottles of cold water, when empty or near empty I have had trouble keeping the fridge at temp, less air to cool they work really good. When we hooked up this trip it was a rush, so warm gear was put in fridge and it had only been on for a night if lucky, with fresh meat from butchers it took a day or 2 to freeze everything and get running well, outside temps of 35 plus didn't help. We usually run it up for a day when freezer starts to ice we load it with frozen stuff and load fridge with cold non critical stuff that way everything chills down, if just run for a day or 2 and pack on departure the fridge doesn't recover from door opening before its on 12v.....once you have cold gear in there it should be good....my freezer can be at minus 12 and fridge will struggle because its empty on hot days....

 

[mikerezny]

Our fridge will easily increase by a few degrees when opening the door in the middle of the day. But if there is a reasonable amount of stuff in the fridge then it will recover in 30 minutes to an hour depending on the ambient temperature. I aim to get the fridge back below 6C and not often below 4C.

I have plastic containers on all the shelves to reduce the loss of cold air when the door is opened.

But that won't be causing your problem. Since the freezer seems to be working, it is unlikely to be a power problem. I assume you have checked that the flue outlet on the top external vent is warm indicating that the boiler is being heated. If you feel inclined, remove th etop external vent and feel th etemperature of the evaporator fins. They should be quite hot, especially on the left-hand side where the "fluid/gas" is coming from the top of the boiler.

Check that you have no ice buildup on the cooling fins in the fridge section. Ice buildup around the thermostat probe will prevent the fridge from regulating the actual fridge temperature correctly.

I suggest to initially put the temperature probe on the cooling fins close to where the thermostat is. That will give an indication that system is at least attempting to cool the fridge. If that also gives high readings, then put the data logger in the freezer close to the cooling plate at the back of the fridge.

On other forums there have been people with 3-way fridges where the freezer works well but the fridge not or hardly at all. The path for the "coolent" is first through the freezer and then through the cooling fins in the fridge. The fridge is 15 years old, and if you are not the first owner, the fridge may not have been treated well by the previous owners. Running these fridges when not level can cause irreparable damage. The easiest test is that the van should be level enough to be comfortable to sleep in.

Just so we are all on the same page, can you please post the brand and model of the fridge? Otherwise you may get replies with information that may not be relevant to your particular fridge.

Another suggestion when quoting fridge temperatures is to also report ambient temperatures. 12C in the fridge in 45C ambient is quite different to getting 12C in 20C ambient. Especially when the door is opened.

On my Dometic 95l RM2350, With an empty fridge, I will feel heat from the flue in less than 30 minutes. After a further hour the back panel of the freezer will be getting cold. After another hour or so the cooling fins in the fridge will feel cool. Temperature in the fridge will start to drop after another hour or so (If I have not opened the door).

Stacking the fridge or freezer with bricks is certainly a great idea for getting the temperature down more quickly. But it will not help in isolating if the fridge or freezer is actually working or not. Filling it up with cold bricks just turns the fridge and freezer into an esky.

cheers
Mike

 

[MDS69]

The problem with a lot of those thermometers or temp gauges is they are instant so any loss of the cool air will show an almost instant change on your display and as mentioned above because the cold air falls out it takes a while for the fridge to recover according to the display. I have read you should have the probe in a brine solution for a more stable reading. I have the digital fish tank temp gauge mentioned elsewhere on this forum for an external display but in the fridge I have an analogue dial that hooks onto the wire shelf and is more stable.
I still have ugly experiences with my 2014 150L 3 way but need to do a few mods like the fans and check the sealing at the rear.

 

[Boots in Action]

The problem with a lot of those thermometers or temp gauges is they are instant so any loss of the cool air will show an almost instant change on your display and as mentioned above because the cold air falls out it takes a while for the fridge to recover according to the display. I have read you should have the probe in a brine solution for a more stable reading. I have the digital fish tank temp gauge mentioned elsewhere on this forum for an external display but in the fridge I have an analogue dial that hooks onto the wire shelf and is more stable.
I still have ugly experiences with my 2014 150L 3 way but need to do a few mods like the fans and check the sealing at the rear.

Yes @MDS69 , there IS value in adding mods to heat absorption fridges. Some of the later models now have fans at the rear as standard whilst others have it as an optional extra. If you have a small internal fan (battery or 12 volt), there is less tendency to have rapid changes of temp displayed on thermometers as the reading is then more of an average of what is in the fridge compartment. It also helps to move the recently introduced hot? ambient air (which has entered whilst door was open) , around and over the face of the evaporator and mix it with the existing cooler air. The warmest part will be at the top of fridge (not under the evaporator!!!) and will stay there until it is cooled before falling towards the bottom of fridge. I am currently looking at the recommended installation for my Thetford fridge and even though mine was "reasonably" installed by Jayco, they still did not do the complete job properly. That is why so many do not operate as well as they should. However, with the help of information from members on this forum, I have been able to rectify these omissions and upgrade the operation considerably. I will send a picture of the installation as recommended by manufacturer as soon as I can.
Noted your comments about how some thermometers are almost instant in changing temperature . This is usually caused by less than desirable/reliable positioning of sensor. Another reason for my explanation of where my sensor was positioned when I did those charts, and having a thermometer which showed temperature " trends" at 10 minute intervals too.

 

[Troy Foz]

So after a couple of visits by a local fridge mechanic it was initially decided that the thermostat was buggered but more investigation was done by another mechanic from the same company and the young fella found that the dial that engages it from AC to GAS etc wasn't engaging properly and had a build up of dirt behind it.
so after all that it was the dial and the fridge has been sitting between 0-3 degrees ever since on the AC and that's empty, bloody hell I wish I knew hahaha although they only charged me $80 for two site visits.

 

[Drover]

Damn, if you had posted a pic of the front if your fridge it should have jogged my memory, mate had to clean up one and replace it later on because of crud which actually corroded it, just forgot about it, too long with a auto push button fridge I'm afraid.....I might start a book with my Van Problem fixes for quick reference...

 

[Troy Foz]

Damn, if you had posted a pic of the front if your fridge it should have jogged my memory, mate had to clean up one and replace it later on because of crud which actually corroded it, just forgot about it, too long with a auto push button fridge I'm afraid.....I might start a book with my Van Problem fixes for quick reference...

Hahaha yea to be honest I did have my reservations about that dial as it didn't click and the off setting is so close to the AC setting and I always wondered how do you know if its actually on or off whist on AC.
oh well $80 wasnt too bad.

 

[Boots in Action]

Damn, if you had posted a pic of the front if your fridge it should have jogged my memory, mate had to clean up one and replace it later on because of crud which actually corroded it, just forgot about it, too long with a auto push button fridge I'm afraid.....I might start a book with my Van Problem fixes for quick reference...

Great idea @Drover!! But would you be able to limit it it to less than the old Melbourne telephone book size??

 

[Troy Foz]

Just returned from the 2 week trip and the fridge didn't miss a beat on 240v & Gas....Winning.

 

[Drover]

Thats the way to go, mines been running near 8 weeks straight on everything and my old computer fan inside hasn't stopped either................mind here in SA I could turn it off for a day it would still be icy.

 

[Boots in Action]

Just returned from the 2 week trip and the fridge didn't miss a beat on 240v & Gas....Winning.

Good to hear of another "success" story @Troy Foz.

 

[BJM]

A few months ago I spent time insulating all sides plus top of my RM2350 as per the instructions.Virtually no insulation fitted by Jayco from new.Appears to have made a large difference with it now running on 3.5 not 4.5 + on the dial when on 240v.