Dometic 3 way fridge

[rojoberry]

It's been a whilebut I've returned to where I know someone will be able to help. My fridge in our 16-49.4 has decided to let me down its not the firstti e butshe does want toworkat all. Pilot lights but nothing coolson 12, 240 or gas. Can someone help I think it's the element???

 

[mikerezny]

It's been a whilebut I've returned to where I know someone will be able to help. My fridge in our 16-49.4 has decided to let me down its not the firstti e butshe does want toworkat all. Pilot lights but nothing coolson 12, 240 or gas. Can someone help I think it's the element???

Hi @rojoberry,
there are three completely separate ways that the fluid in the boiler is heated:
1: a 12V element
2: a 240V element
3: heat from the gas

If the fridge is not cooling on gas, 12V, or 240V it is probably not an element.

My first question would be: is the flue outlet at the top of the fridge getting hot?

Second question, is the pipe leading into the condensor fins at the back of the fridge getting hot?

best wishes
Mike

 

[rojoberry]

Hi @rojoberry,
there are three completely separate ways that the fluid in the boiler is heated:
1: a 12V element
2: a 240V element
3: heat from the gas

If the fridge is not cooling on gas, 12V, or 240V it is probably not an element.

My first question would be: is the flue outlet at the top of the fridge getting hot?

Second question, is the pipe leading into the condensor fins at the back of the fridge getting hot?

best wishes
Mike

 

[rojoberry]

The flue out let is not sure on you second point

 

[Drover]

Okay, if the flu outlet is getting hot then the thing is cooking and by the way there is no pilot light on the fridge the little flame is there all the time, it's what does the heating up when on gas, now the other thing is since it doesn't work on 240 or 12 v then I can assume you have run it for a couple of hours as this is needed before it will show any sign of cooling................when on 240v the flu will also get warm. Van must be level.
After running for a couple of hours remove the top vent and feel the pipes and condensor fins they should be getting warm/hot if they are cold then you have a fluid flow problem or the fluid has leaked.
More than likely if not used for ages and not parked level it may need a bit of a windy bumpy road to shake things up then park up nice and level and try it again.

 

[Boots in Action]

There is just one other area that could cause lack of cooling, although less likely if fridge has been working previously. In the outlet flue is a spiral baffle which restricts or reduces the the heat loss up the flue pipe. Its main use is to contain as much heat as possible from the heating elements close to the boiler (be they gas or electrical heaters) . It ensures that MAX heat is applied to the boiler for best operation on heat absorption fridges and still allows fumes to vent out. If this is broken (burn out to nothing) or not in position, heating of the boiler will be reduced and as a result cooling will be less than desired even though you will feel heat at the vent outlet. All the other suggestions are still valid too especially if fridge has not been used for some time. Unfortunately, to check this, it will/may be necessary to remove fridge to get access to boiler vent heating box. Just a possibility??

 

[mikerezny]

There is just one other area that could cause lack of cooling, although less likely if fridge has been working previously. In the outlet flue is a spiral baffle which restricts or reduces the the heat loss up the flue pipe. Its main use is to contain as much heat as possible from the heating elements close to the boiler (be they gas or electrical heaters) . It ensures that MAX heat is applied to the boiler for best operation on heat absorption fridges and still allows fumes to vent out. If this is broken (burn out to nothing) or not in position, heating of the boiler will be reduced and as a result cooling will be less than desired even though you will feel heat at the vent outlet. All the other suggestions are still valid too especially if fridge has not been used for some time. Unfortunately, to check this, it will/may be necessary to remove fridge to get access to boiler vent heating box. Just a possibility??

Hi @Boots in Action,
might be a silly idea.... but, how feasible do you think it would be to drill a hole in the bench above the flue outlet big enough to pull out the spiral baffle to inspect, clean, and/or replace it?

If it would work, it might be easier than removing and re-installing the fridge.

That prompts a second question. How much work is involved in removing the fridge. Once our Penguin is out of warranty, I might think about doing this so that I can do a proper job of insulating the spaces around the fridge, install a couple fans directly under the condensing fins, put in a baffle to separate the hot air from around the boiler area getting anywhere near the back of the fridge or the condensing fins, and provide more insulation around the boiler to reduce heat loss.

cheers
Mike

 

[Drover]

Fitting instructions are usually in the manual for the fridge but usually a couple of screws behind fascia.....................Don't think drilling thru the bench top would allow much access.

Fans are best positioned above the the condenser to draw the air, gives better air flow, you will find that following the gap allowance described in the fitting instructions combined with the fans the walls stay a lot cooler.

 

[mikerezny]

Fitting instructions are usually in the manual for the fridge but usually a couple of screws behind fascia.....................Don't think drilling thru the bench top would allow much access.

Fans are best positioned above the the condenser to draw the air, gives better air flow, you will find that following the gap allowance described in the fitting instructions combined with the fans the walls stay a lot cooler.

Hi @Drover,
I mounted one fan on the top vent and all worked well. So I thought, two is better than one, so I mounted another one beside it.
It didn't work as well. The main problem was that there was so much airflow, it was dragging air from around the boiler area as well as over the condenser. In fact, it was drawing hot air from the boiler over the condenser fins as well.

The solution I would like is to put a baffle between the condenser area and the boiler area. Keep the boiler area as hot as possible for heating efficiency and have the fans draw only from the bottom vent over the condenser.

I made a cut out of the somewhat complicated baffle, but it has been held up since I can't figure a way to make the baffle robust enough to be reliable and flexible enough to get it into place. I decided that it will have to wait until the van is out of warranty and then pull the fridge out.

In the mean time, I used the strongest fan (Be Quiet pure Wings, draws 100 mA) and mounted it on the external vent far to the left, as far away from the boiler as possible. Boiler is now running hot again and the condenser is getting good airflow almost all from the bottom vent. I have wrapped aluminum lined polyester around the back and top of the boiler to keep the heat off the walls.

cheers
Mike

 

[Drover]

Trying to think back to when I did some work on a Swan, it was pretty packed in the back I must say, I fitted a 3" computer fan, fitted a baffle to direct air to vents not inside and got a freezing fridge at 3, so they were happy but never noticed any extra heat from the boiler.
The chimney hasn't come apart has it ? have found that before top is all good but the bottom has fell off the flu, stupid system which I sorted with a rivet or 2.

 

[Boots in Action]

Hi Mike, Yes, silly idea to permanently have a hole in the bench forever, even if you plugged it!! With your new Penguin, it is HIGHLY unlikely that there would be any failure with the spiral baffle. It is just a bit of twisted metal that fits snugly into the vent tube connected to a bit of wire to hang on the vent tube to pull it out. It does not wear, but after many many years of heating, it MAY start to disintegrate. Failure to get enough heat is usually caused because in second hand fridges, someone, not knowing what they are doing, has lost it or forgotten to put it back in when cleaning the heating vent of spiders, mud wasps etc. when van has not been used for sometime. Not a worry for you I would say.
In answer to your second question, it is pretty straight forward, especially for a smart man like you. Disconnect the 240 volt and 12 volt connections, then the gas connection (use TWO spanners!!). There should/may be a couple of mounting screws at the back. At the front, remove the fridge door and you will see about 4 mounting screws through the front cover of fridge. Remove these and you should be on your way to carefully pushing/pulling the fridge forward and out.
The fridge in my Penguin is a very snug fit with insulation on both sides. It does have a deflection baffle to direct the air through the fins at the top of the fridge, but DID NOT have a deflection shield at the top of the fridge to direct air OUT of the top vent. Manufactured one and now fitted, so no hot air hanging around at the top under bench. It will be very difficult to separate the heat from the boiler from the rest of the workings and in fact may be detrimental as there is heat to be dissipated throughout the back of the fridge. You can get enough air flow by just attaching the fans to the vents - one pushing and one pulling air. I have two 120mm X 120mm computer fans each moving in excess of 93 cubic feet per minute at 2400 rpm - and very quiet too. Current draw is .25A each. Approx $3.60 each from Ebay. Make sure you get these as some do not state volume moved. In fact, the gale of air they produce out the top vent is usually cool within 15 minutes, so I turn them off and on as needed. A thermostat control would be better but all the ones I have seen come on too late (Hot) and off when too cool for Queensland temps. Good luck and be careful!!!

 

[Boots in Action]

Hi Mike with the Penguin like me, I made the top baffle for the back of my fridge out of sheet aluminium (flashing?). It is able to be bent into different shapes, is strong enough to stay where placed, is easy to work with AND is SHINY on both sides to reflect heat. Bought a roll of same at Bunnings. Could be the answer to your problem in constructing baffles for your fridge. Worked for me!!!

Hi @Drover,
I mounted one fan on the top vent and all worked well. So I thought, two is better than one, so I mounted another one beside it.
It didn't work as well. The main problem was that there was so much airflow, it was dragging air from around the boiler area as well as over the condenser. In fact, it was drawing hot air from the boiler over the condenser fins as well.

The solution I would like is to put a baffle between the condenser area and the boiler area. Keep the boiler area as hot as possible for heating efficiency and have the fans draw only from the bottom vent over the condenser.

I made a cut out of the somewhat complicated baffle, but it has been held up since I can't figure a way to make the baffle robust enough to be reliable and flexible enough to get it into place. I decided that it will have to wait until the van is out of warranty and then pull the fridge out.

In the mean time, I used the strongest fan (Be Quiet pure Wings, draws 100 mA) and mounted it on the external vent far to the left, as far away from the boiler as possible. Boiler is now running hot again and the condenser is getting good airflow almost all from the bottom vent. I have wrapped aluminum lined polyester around the back and top of the boiler to keep the heat off the walls.

cheers
Mike

Fitting instructions are usually in the manual for the fridge but usually a couple of screws behind fascia.....................Don't think drilling thru the bench top would allow much access.

Fans are best positioned above the the condenser to draw the air, gives better air flow, you will find that following the gap allowance described in the fitting instructions combined with the fans the walls stay a lot cooler.

Oh MIGHTY DROVER, one who has done most things and knows most things, I wish to challenge your advice on the positioning of external fans to cool the back of the fridges.
Firstly, when fans are placed at the top vent above cooling fins, a low pressure area is created below and so air from the bottom vent (and anywhere else if not sealed) rushes in to equalize the pressure to be the same as outside. The reverse applies if the fans are placed in the lower vent. The area around the fridge is pressurized and air escapes out through the upper vent and anywhere else that is not blocked.

It is a safety factor that the seal around the front of the fridge must be in good condition to prevent burnt gases from entering the van and putting you into a permanent sleep should the vent/s FOR THE FRIDGE be restricted in some way. Not to be confused with the danger from leaking propane gas inside which is heavy and provision is made for it to exit via the vent in the bottom of your door. Basically, the area around the fridge SHOULD be a sealed box. As hot air rises, it usually exits by the top vent and nowhere else!!.

Mike, take notice if you remove you fridge at some time - self adhesive foam sealant or the like is available at Bunnings.

Airflow in the first example can never increase in volume as it is restricted to the opening of the inlet vent (or other opening). In the second case air volume exiting can never increase as it is similarly restricted, no matter how many fans are in use.The ONLY way to move more air in volume is to increase the velocity of the airflow (by turbo charging it). That is done by having a fan in place to speed up the aiflow (velocity). The bottom line is that it is better to have similar fans (in volume capacity anyway) to move the air FASTER . I have it that way for my fridge cooling. That is the theory anyway!! Would appreciated your comments for this "upstart" and also from any other thread followers who wish to have their 2 cents' worth. That way we all learn.

 

[mikerezny]

Hi Mike with the Penguin like me, I made the top baffle for the back of my fridge out of sheet aluminium (flashing?). It is able to be bent into different shapes, is strong enough to stay where placed, is easy to work with AND is SHINY on both sides to reflect heat. Bought a roll of same at Bunnings. Could be the answer to your problem in constructing baffles for your fridge. Worked for me!!!
[/QUOTE

Hi @Boots in Action,
both minds think alike. Aluminium flashing was indeed also the best I could find. I am way too tight to buy a complete roll when I only needed 300-400mm. I tried to find other places to buy it by the metre without any luck.

But, just by chance, I was discussing this with a mate of mine who built a mud-brick bungalow / music room some years ago and he had a few metres left over.

So, indeed, I have some aluminium flashing. The next problem I still haven't sorted is how to get into the top vent to robustly screw it to the back wall and the benchtop. Hence, I have put it on the backburner until I take the fridge out and do it properly. I will then do the side, top and bottom insulation properly and put the top deflector in.

The warranty expires on November 2017, so I will pull the fridge out soon after that and hopefully get it sorted before summer.

kindest regards
Mike

 

[Drover]

Sorry if I offend you @Boots in Action , the advice on fans is actually what you will find in most publications pertaining to the subject and it works well I have found, your views are more than welcome here and no need to challenge with sarcasm as we embrace all opinions unlike some other places.........................you see quite often there is more than one way to do things.

 

[Boots in Action]

Sorry if I offend you @Boots in Action , the advice on fans is actually what you will find in most publications pertaining to the subject and it works well I have found, your views are more than welcome here and no need to challenge with sarcasm as we embrace all opinions unlike some other places.........................you see quite often there is more than one way to do things.

Drover, you do not need to apologize to ME. I am the one who will apologize to YOU!! It was NEVER intended to be sarcastic, just a referral and acknowledgement of all you past experiences and knowledge obtained over the years. I DO consider myself to be the "upstart" on this forum - a Johnny come lately so to speak who had the temerity to disagree with you ! Bouncing my idea off someone like yourself was sure to get a good response on what you thought was good or bad. So Sorry. But thank you and any other follower who sent me a "like". It is appreciated and I am happy to try to help others with all sorts of ideas. As was sent to me earlier, I too can "take it on the chin" and move on with everyone. Kindest regards

 

[Moto Mech]

Best thing you can ever do to your 3way fridge is chuck it on the tip and fit either a compressor fridge or a inverter fridge. Problem solved......

 

[mikerezny]

Best thing you can ever do to your 3way fridge is chuck it on the tip and fit either a compressor fridge or a inverter fridge. Problem solved......

Hi @Moto Mech,
do you know of any inverter fridges for use in caravans?
It looks like the extra efficiency of these fridges would be very welcome.
Some of the advertising from LG and Samsung claim almost 50% reduction using a digital inverter.

One other question. I know that just about anything used exclusively for camping is priced at a premium. So, it seems plausible that using a standard 240V fridge in a van and powering it from the van battery via an efficient 12V - 240V inverter would work.
If so, it might be a much less expensive option.

Are you aware of anyone trying this?

kindest regards
Mike

 

[Bellbirdweb]

Hi @Moto Mech, So, it seems plausible that using a standard 240V fridge in a van and powering it from the van battery via an efficient 12V - 240V inverter would work.
If so, it might be a much less expensive option.

Are you aware of anyone trying this?

The biggest issue with inverters is that they are not efficient. Even the best ones are only 85% efficient so you'd need to find a really efficient inverter fridge that could overcome the inverter conversion, and compete with a 12v compressor fridge.

Interesting to see though as this new technology may eventually trump the old
compressor and 3 way technology

 

[Dobbie]

I definately have to disagree again....the three way is fine for 99pc of the time it's used and the other 1pc can be minimised by careful use....not removed, but minimised.

The alternative is hellishly expensive and heavy unless you go with lithium batteries...also still expensive .....

There seems to be a huge move to and discussion of alternative fridge power. Maybe I'm out of the loop and out of date ...or maybe I don't read the articles or follow the forums but....

I really can't see the point in looking at expensive alternatives when what is standard on the van is adequate.

As said, we've used the three way fridges for yonks and never had a problem ....we've also used Waecos and found their power demands ridiculous, particularly when free camping.

It seems that to get the little bit extra in fridge efficiency it's necessary to spend a huge amount....I'd rather spend my money on something else!

(We do use fridge fans, a fridge awning when required and have an Accurite fridge monitor...only recent issue is the need to mildly defrost the freezer in humid conditions but that was once only and it took 30 minutes)

I hate spending money where I'm not convinced it's necessary.

But again....to each his own.

 

[Bellbirdweb]

I definately have to disagree again....the three way is fine for 99pc of the time it's used and the other 1pc can be minimised by careful use....not removed, but minimised.

The alternative is hellishly expensive and heavy unless you go with lithium batteries...also still expensive .....

There seems to be a huge move to and discussion of alternative fridge power. Maybe I'm out of the loop and out of date ...or maybe I don't read the articles or follow the forums but....

I really can't see the point in looking at expensive alternatives when what is standard on the van is adequate.

As said, we've used the three way fridges for yonks and never had a problem ....we've also used Waecos and found their power demands ridiculous, particularly when free camping.

It seems that to get the little bit extra in fridge efficiency it's necessary to spend a huge amount....I'd rather spend my money on something else!

(We do use fridge fans, a fridge awning when required and have an Accurite fridge monitor...only recent issue is the need to mildly defrost the freezer in humid conditions but that was once only and it took 30 minutes)

I hate spending money where I'm not convinced it's necessary.

But again....to each his own.

I'm actually with you @Dobbie.

I've had not a single problem with our 3 way, no fans, ran it in 45+ degree heat in QLD over Christmas, had frozen ice cream (I don't drink so it's my major reason for even having a fridge LOL) and ice for drinks everywhere.

I only need 240w of solar and can keep going for several weeks off grid.

I understand they can be fiddly at times, but a bit of patience and general knowledge and they seem the ideal solution to me.

I guess that's why they are still standard on most vans instead of the compressor fridges.

Will still be interesting to see if anyone does a 12v inverter fridge though.