14' Series Dometic fridge playing up

[Ted farkas]

Hi,
Have a 14 ft outback with a Dometic fridge 6 years old. Worked like a charm (even of square). Suddenly not cooling on ac DC or gas....flue is hot.

Only thing I can think of is ammonia refrigerant has leaked out. Anyone had Same problem...worked 2 months ago. Everything looks good visually. Thought I smelt a slight ammonia smell over the years no ON E else has noticed...

Any tips appreciated.

Thanks
Ted

 

[Drover]

Either that or the stuff has blocked up, possibly if parked at an acute angle for awhile, sometimes a good bumpy drive will shake it clear............... the experts will remove fridge and roll it around the room a few times, you have let it run for 24 hrs at least i assume ??? ...........While the flu is getting hot what about the pipes themselves are they completely cold all along or have a small hot spot ?? Ideally they should go from quite warm to damn Hot, thats the pipes not the cooling fins.......................depending on how long ago the leak was I have heard you can spot a stain on the pipe, if it is a leak though its a shop job, not sure if they fix or bin them.

Is it an AES (auto) fridge or the knob job, model #....................???

 

[Boots in Action]

Hi,
Have a 14 ft outback with a Dometic fridge 6 years old. Worked like a charm (even of square). Suddenly not cooling on ac DC or gas....flue is hot.

Only thing I can think of is ammonia refrigerant has leaked out. Anyone had Same problem...worked 2 months ago. Everything looks good visually. Thought I smelt a slight ammonia smell over the years no ON E else has noticed...

Any tips appreciated.

Thanks
Ted

Hi @Ted farkas , I think that @Drover has already covered some of the points, but I believe that if controls are okay (working on gas and 240v) and the element is heating okay, then you have a major problem. If you take off the vent covers behind your fridge, it will be obvious if it has a leak, but I don't think that is likely . As you have said that you have operated your heat absorption fridge off level at times that has caused the heating tube to become blocked and so no flow of gaseous and liquid ammonia. The attached will explain what has probably happened and the result of operating "off square".

 

[Ted farkas]

Thanks
It's a knob version....no sign of leaks only other thing I can think of is a thermistor problem

 

[Boots in Action]

@Ted farkas , Regarding my reply, if you watch through the attached link, about half way through, it is explained and shows diagrams of what happens to the heating tubes getting blocked and also what to look for if there is a leak- very unlikely! I have had to sort out two friends' fridge problems which were not cooling - one in a motorhome and the other a portable 3 way fridge only 2 to 3 years' old. Both had the same problem caused by operating too long off level. In both cases, I tried to free up the blocked tubes by shaking/inverting and turning on different sides for periods of time (up to 24 hours unit NOT operating), but although I did succeed in getting the heat above the burner/heater a little higher towards the condenser at the top, still no joy in both cases. If there is no heat at the condenser fins (that radiator thing at the top), then that is a positive sign that ammonia gas/liquid is not coming up from the boiler. Owners of both non working fridges now very much aware of the need to be level as both have had to purchase new fridges as not possible to repair, just as video states. Tough way to learn!!

 

[Boots in Action]

Thanks
It's a knob version....no sign of leaks only other thing I can think of is a thermistor problem

If it is heating by gas and by 240v, then it will not be a thermistor problem.

 

[Drover]

If it is heating by gas and by 240v, then it will not be a thermistor problem.

Nah, he said No Work on any of them but flu hot.....

If nothing after a 24hr run, on 240 or Gas (12v is irrelevant) hot flu but warm bits in fridge than points to ammonia drama as even if thermo is faulty the fins/freezer will get cool .... Follow the the shake route booties said!

 

[mikerezny]

Hi,
here are my suggested sanity checks for determining if the fridge is working.

1: connect fridge to one power source, 240V is the most practical. Ensure van is reasonably level. Put a thermometer in both the freezer and the fridge.

You have stated that you have a manual three-way fridge, but please supply brand and model number, otherwise we are all trying to guess what you have.

2: select AC as energy source and turn temperature control to maximum cooling. (This is where we need to know brand and model number!!!!)

3: Wait for 30 minutes.

4: Remove bottom vent and check that the boiler on the RHS is warm / hot. Check that you can detect heat coming from the flue outlet on the RHS of the top external vent.

5: Remove top external vent. Ensure flue outlet is sitting properly on the top of the boiler.

6: check that the top pipe running from the top of the boiler across to the condenser fins is also warm / hot.

7: Wait another 60 minutes.

8: Check the metal plate at the back of the freezer. It should feel a little cooler. Take a note of the temperature in the freezer.

NOTE: Do not put freezer blocks in the fridge or freezer. We are trying to see if the fridge is functioning as a fridge not whether it will work as an esky.

9: Wait another 2 hours.

10: Check the RHS cooling fins in the fridge compartment. They should feel slightly cooler. Take a note of the temperature.

11: Check the plate at the back of the freezer. It should be cold and there should now be some condensation on the plate. Take a note of the temperature. It should be cooler than the first measurement.

Do not open the fridge at any other time. Each time you open the fridge, it looses the cold air and greatly increases the time it takes to cool, especially if the fridge and freezer are empty.

The cooling path is first through the freezer and then through the fridge. The fridge will not start to cool properly until the freezer is cold.

After another 6 hours check the freezer plate and fridge cooling fins. They should be cold. The freezer temperature should be below 0C and there should be ice condensation of the freezer plate. The fridge temperature should be below 10C.

Report on your findings and we may be able to help further.

If after these simple tests the fridge is not cooling but the boiler is hot, one thing worth checking is if the flue is blocked. Perhaps something has built a nest in there. The instruction manual, (easily found online) details how to clean a flue. However, this will really be more of an issue when running the fridge on gas.

take care
Mike

 

[Boots in Action]

Hi,
here are my suggested sanity checks for determining if the fridge is working.

1: connect fridge to one power source, 240V is the most practical. Ensure van is reasonably level. Put a thermometer in both the freezer and the fridge.

You have stated that you have a manual three-way fridge, but please supply brand and model number, otherwise we are all trying to guess what you have.

2: select AC as energy source and turn temperature control to maximum cooling. (This is where we need to know brand and model number!!!!)

3: Wait for 30 minutes.

4: Remove bottom vent and check that the boiler on the RHS is warm / hot. Check that you can detect heat coming from the flue outlet on the RHS of the top external vent.

5: Remove top external vent. Ensure flue outlet is sitting properly on the top of the boiler.

6: check that the top pipe running from the top of the boiler across to the condenser fins is also warm / hot.

7: Wait another 60 minutes.

8: Check the metal plate at the back of the freezer. It should feel a little cooler. Take a note of the temperature in the freezer.

NOTE: Do not put freezer blocks in the fridge or freezer. We are trying to see if the fridge is functioning as a fridge not whether it will work as an esky.

9: Wait another 2 hours.

10: Check the RHS cooling fins in the fridge compartment. They should feel slightly cooler. Take a note of the temperature.

11: Check the plate at the back of the freezer. It should be cold and there should now be some condensation on the plate. Take a note of the temperature. It should be cooler than the first measurement.

Do not open the fridge at any other time. Each time you open the fridge, it looses the cold air and greatly increases the time it takes to cool, especially if the fridge and freezer are empty.

The cooling path is first through the freezer and then through the fridge. The fridge will not start to cool properly until the freezer is cold.

After another 6 hours check the freezer plate and fridge cooling fins. They should be cold. The freezer temperature should be below 0C and there should be ice condensation of the freezer plate. The fridge temperature should be below 10C.

Report on your findings and we may be able to help further.

If after these simple tests the fridge is not cooling but the boiler is hot, one thing worth checking is if the flue is blocked. Perhaps something has built a nest in there. The instruction manual, (easily found online) details how to clean a flue.

take care
Mike

Hi Mike @mikerezny , perhaps we are all omitting one very important thing. Is the fridge in @Ted farkas's fridge level (and properly levelled for test!!) as he is now not cooling?? There have been several instances on this forum of members claiming fridge failure, when all that was wrong was not level enough!! Vans parked in driveway and uphill or on an angle in similar situations whilst connected at home. Amazing how they come back and advise that the fridge has miraculously started working again when they properly level fridge.

@Ted farkas - the parameters for proper operation and particularly for this test are as follows:

When facing fridge door, the fridge must be within 3 degrees of vertical as measured from hitch point at front of van to rear of van.
Also when facing front of fridge door, the fridge must be within 6 degrees of vertical across the van as measured wheel to wheel.

If this is done, then we really know how to help.

 

[mikerezny]

Hi Mike @mikerezny , perhaps we are all omitting one very important thing. Is the fridge in @Ted farkas's fridge level (and properly levelled for test!!) as he is now not cooling?? There have been several instances on this forum of members claiming fridge failure, when all that was wrong was not level enough!! Vans parked in driveway and uphill or on an angle in similar situations whilst connected at home. Amazing how they come back and advise that the fridge has miraculously started working again when they properly level fridge.

@Ted farkas - the parameters for proper operation and particularly for this test are as follows:

When facing fridge door, the fridge must be within 3 degrees of vertical as measured from hitch point at front of van to rear of van.
Also when facing front of fridge door, the fridge must be within 6 degrees of vertical across the van as measured wheel to wheel.

If this is done, then we really know how to help.

Hi @Boots in Action,
it is challenging try to offer assistance remotely when we have no idea on the experience of the person requesting help.

The omissions are usually related to determining at what level (pun intended!) to offer advice.

I assumed the fridge was reasonably level since the OP stated that the fridge had worked in the past when not level. Assuming, perhaps incorrectly, that the present problem was happening with the fridge level.

I actually covered that in point 1 of my post:
1: connect fridge to one power source, 240V is the most practical. Ensure van is reasonably level. Put a thermometer in both the freezer and the fridge.

take care
Mike

 

[Boots in Action]

Hi @Boots in Action,
it is challenging try to offer assistance remotely when we have no idea on the experience of the person requesting help.

The omissions are usually related to determining at what level (pun intended!) to offer advice.

I assumed the fridge was reasonably level since the OP stated that the fridge had worked in the past when not level. Assuming, perhaps incorrectly, that the present problem was happening with the fridge level.

I actually covered that in point 1 of my post:
1: connect fridge to one power source, 240V is the most practical. Ensure van is reasonably level. Put a thermometer in both the freezer and the fridge.

take care
Mike

Oh so true @mikerezny . I overlooked that very important point in my first reply. Only picked up on the fact that member had admitted to using fridge "of square" on occasions before and not noticed any significant effect AT THAT TIME. May now have run out of time in getting away with it!! Depending on how long and how often used "of square" will determine the outcome of this conversation. And yes, did notice your instruction to have van (and fridge) reasonably level, but for this remote test, wanted to make sure we have a known starting point in isolating problem. The fact that heating by 240v and gas still produced no cooling and flue was stated as hot, immediately made me think of more serious problems caused by use "of square". Considering the number of times this has come up on this and other forums, it is surprising that this important point in operating absorption fridges has not yet got through to everybody.

 

[mikerezny]

Hi @Boots in Action,
yes, whilst it is reasonable well known that an absorption fridge must be reasonably level to operate correctly, it is not at all understood that irreversible damage can occur when the fridge is operated when not level.

The user manual is quite clear on the need to have the fridge level when the van is stationary. However, it does not discuss the permanent damage that can occur when operated when not level.

take care
Mike

 

[Ted farkas]

Hi guys
Thanks for the replys. Been using the fridges for years and aware of there nuisances. However never read anywhere that using unlevel may cause damage, I like many others just assumed it would be inefficent only. I reckon it's a block somewhere....I'm on the road so hopefully it'll rattle loose and I'm gonna tap the small tubes..... learnt a lot about absorption fridges in the last 2 hours.... thought they were basic

Cheers ted

 

[Boots in Action]

Read the OP again and base your replies on that, hot flue, no chill inside, van level, @Ted farkas sounds like he knows where he's going....

@Drover , @mikerezny and I have answered based on ALL info provided by @Ted farkas . I had a look at all his info and cannot find any place where he said his van under test is level. Your last paragraph is yet to be established. If you operate "off square", that does not augur well for knowledge on the operation of absorption fridges. Just read his last message and proves my point. At least he has had the courage to admit his lack of knowledge on how they work.

 

[Boots in Action]

Hi guys
Thanks for the replys. Been using the fridges for years and aware of there nuisances. However never read anywhere that using unlevel may cause damage, I like many others just assumed it would be inefficent only. I reckon it's a block somewhere....I'm on the road so hopefully it'll rattle loose and I'm gonna tap the small tubes..... learnt a lot about absorption fridges in the last 2 hours.... thought they were basic

Cheers ted

Thanks for responding @Ted farkas . At least you now have some idea on what may have gone wrong. All is not lost ...yet. If still not working when you get home, your LAST chance will be to remove fridge and tip it around a few times and left that way overnight. Then try again whilst out of van with connection to 240 volt power. It may take several attempts and even then, positive result is doubtful, but worth a try anyway. Good luck and let us know how you go. Your misfortune will be someone else valuable warning. Cheers.

 

[Boots in Action]

Hi @Boots in Action,
yes, whilst it is reasonable well known that an absorption fridge must be reasonably level to operate correctly, it is not at all understood that irreversible damage can occur when the fridge is operated when not level.

The user manual is quite clear on the need to have the fridge level when the van is stationary. However, it does not discuss the permanent damage that can occur when operated when not level.

take care
Mike

Your post @mikerezny has a lot of truth in it.

 

[Ted farkas]

Hi guys
Thanks for the replys. Been using the fridges for years and aware of there nuisances. However never read anywhere that using unlevel may cause damage, I like many others just assumed it would be inefficent only. I reckon it's a block somewhere....I'm on the road so hopefully it'll rattle loose and I'm gonna tap the small tubes..... learnt a lot about absorption fridges in the last 2 hours.... thought they were basic

Cheers ted

 

[Ted farkas]

I'll let you know how I go.....I meant to say nuances previously.

I did a lot of googling before I got to here and not once did I see anything mentioned on permanent damage operating of square. Had an old camper Electrolux from 30 years ago handed down that never missed a beat (absorption).

On the bright side , by pure coincidence I purchased an evakool from Repco just before the trip for the tow rig as an accessory so it has now filled the void temporarily, so the trip goes on. Top bit of kit so far Aussie company apparently too.

Cheers
Ted

 

[Boots in Action]

I'll let you know how I go.....I meant to say nuances previously.

I did a lot of googling before I got to here and not once did I see anything mentioned on permanent damage operating of square. Had an old camper Electrolux from 30 years ago handed down that never missed a beat (absorption).

On the bright side , by pure coincidence I purchased an evakool from Repco just before the trip for the tow rig as an accessory so it has now filled the void temporarily, so the trip goes on. Top bit of kit so far Aussie company apparently too.

Cheers
Ted

Yes Ted @Ted farkas, @mikerezny mentioned that earlier. It is only when you get into the operation of absorption fridges that incorrect operation problems are explained fully. You are not the first person to fall into that trap, but there are several posts on this earlier. That is why the video on absorption fridges is so important as it brings up the pitfalls of improper operation long term. When this conversation first came up, I was able to source several items of value to members, including that one regarding the slow build up of sodium chromate crystals - not evident at first - but finally catches up and blocks the percolator tube in boiler. Speed of blockage all depends on how far off level, how long and how hot the boiler gets when water/ammonia mixture is not moving. There is another site too on how this happens in greater detail, which I will send to you when I find it again. Happy travels.

 

[Drover]

Sorry you think that Mike, you both tend to rabbit on and the original question tends to get buried before a few simple questions get answered..... I'll just leave it to you to sort out in future...............