HELP!! 3 way fridge. Flue hight above waterline??

MANXPEDRO said:
Thank you all for your ideas and comments!

To reply to a few earlier comments, my boat IS seagoing, but only coastal, not round the world, so never more than a few hours away from a port!

My intention is to vent the flue out through a skin fitting via the side of the hull. Before it goes through the skin fitting, there will be a swan neck inside, to prevent water going into the flue pipe.

The boat is NEVER left unattended with the gas on, so no worry about others fenders melting!!!!


I feel there's a 50/50 sort of balance for and against these fridges, from what people say.

Well, I bought one yesterday. A second hand one from a horsebox! (I'd love a new one, but SWMBO could find more uses with the money than spent on a fridge!!).

Anyway, it cost me £30. He said the 12 and 240 side of things were not working, but the gas was. I took it home, cleaned it down and plugged it into the mains. After a couple of hours, i'd made ice, and the box was starting to cool down!!!! I've not tried the gas or 12v yet, but need to rig up a supply (job for today!!).

Now I need to look into the T-shaped fitting, which fits onto the outlet of the burner. It is on an angle where the gasses will go up through the pipe, but will also be able to vent 'downwards'?? back into the area around the back of the fridge area. Any ideas???

Thanks again to you all for helping me with this!
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The flue should always run upwards. A swan neck could cause the flue not to draw. Ours vents into the cabin to get round the water ingress. I suspect that the flue is open at the bottom to allow a draft, etc which seems like the tee piece. The back does get warm but as long as there is ventalation and no surfaces that could burn closer than 2" everything should be ok. Dometic took over Electrolux I believe quite a few years ago. Reading other comments I am glad that I have not bothered with the 12 volt side as I only have an outboard to charge the batteries when away from marinas.
 
Boathook said:
Mine is still fitted with a gas fridge. Also uses 240 and 12 volt though its not wired up for 12v. Works very well even when sailing and stays alight 99% of the time. If it does go out the thermal couple shuts down the 'burner'. Mine vents into the cabin and a check with a CO meter showed that I should worry more about the cooker before anyone comments.
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I'm pleased to hear I'm not the only one! I agree with others that the 12v function is hardly worth using. I use mine on an inverter when motoring (monohull) or on the rare occasions mains 230v is available. At anchor on gas. Absolutely essential kit!

I thought my 35year old top-loader had died through corrosion recently. Only after buying a replacement did I try the old trick of leaving it upside down for a day. Lo and behold it started working perfectly again!

Edit: Some forced ventilation of the condenser (a 12v computer fan works well and uses very little power) improves efficiency dramatically. My new fridge even has a a fan built in though as designed this only operates in 12v cooling mode. Promptly modified.


Vic
 
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Boathook said:
The flue should always run upwards. A swan neck could cause the flue not to draw. Ours vents into the cabin to get round the water ingress. I suspect that the flue is open at the bottom to allow a draft, etc which seems like the tee piece. The back does get warm but as long as there is ventalation and no surfaces that could burn closer than 2" everything should be ok. Dometic took over Electrolux I believe quite a few years ago. Reading other comments I am glad that I have not bothered with the 12 volt side as I only have an outboard to charge the batteries when away from marinas.
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Yeah, i get your point about the flue going straight up, to create the draw. The T-piece did have me puzzled, as to why it'd be connected to the flue pipe on one side, but the others left open (probably with the venturi effect??).

I'm supprised that yours vents into the cabin. Am i not right in thinkiong there'd be an issue with carbon monoxide???
 
MANXPEDRO said:
I'm supprised that yours vents into the cabin. Am i not right in thinkiong there'd be an issue with carbon monoxide???
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Your cooker vents into the cabin, doesn't it?

As long as the combustion is "complete", ie getting enough oxygen, you get CO2 and H2O. It's only when the intake air to the burner is restricted that you get CO, so in theory a well-maintained gas fridge should be fine.

Trouble is, the things are notorious for rusting internally and causing exactly the airflow restriction you don't want. In the US there's a campaign (including cash grants) to get people to scrap old gas or paraffin absorbtion fridges that have stood rusting in their holiday cabins and hunting shacks for donkey's years and are now belching out CO. The web site for that campaign says that if you insist on keeping it, you should move it outside into a shed or shelter and make sure children don't use the shelter as somewhere to play in.

Personally, I wouldn't be comfortable with one on board my boat.

Pete
 
I would definitely vent outside. You don't leave your cooker running overnight. On a still night, even with windows open, a small amount of CO could fill up the hull and be dangerous. Ours vented into the cockpit side with a 90 deg elbow protruding slightly into the cockpit, so if the cockpit ever filled with water some got down below via the flue (and engine controls) but that was pretty rare. The elbow kept rain and spray out of the flue and still allowed a reasonable draft.
 
MANXPEDRO said:
Yeah, i get your point about the flue going straight up, to create the draw. The T-piece did have me puzzled, as to why it'd be connected to the flue pipe on one side, but the others left open (probably with the venturi effect??).

I'm supprised that yours vents into the cabin. Am i not right in thinkiong there'd be an issue with carbon monoxide???
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See my post number 9. The cabin is never sealed when on board so not an issue. Also the flame is about the size of a pilot light.
 
You can't vent these outside as the flame will blow out. I had one running on gas for 20 years with the vent into the cabin through a louvre vent on the work-top. Never died once from monoxide fumes! Also worked fine on gas when under way. On 12 volt it froze everything solid as these aren't thermostatically controlled on 12 volt.

Took the door off the freezer compartment which made the whole fridge much cooler and it still made a few ice cubes.
 
PCUK said:
You can't vent these outside as the flame will blow out. I had one running on gas for 20 years with the vent into the cabin through a louvre vent on the work-top. Never died once from monoxide fumes! Also worked fine on gas when under way. On 12 volt it froze everything solid as these aren't thermostatically controlled on 12 volt.

Took the door off the freezer compartment which made the whole fridge much cooler and it still made a few ice cubes.
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I discoverd that on ours by accident as the freezer compartment door broke of , did have to defrost more often then tho !
 
Re 3way

You are not alone as the idea of useing a 3 way. The US built Gemini has used them for years. I have not heard of much problems wikth them. So you might study them before you attempt to install one yourself.
As I see it there are several problems.
Safety. Propane it very explosive. So you must take care to prevent leaks, and get rid of the explosive gas it you have a leak. You must have a separate line for the refrigerator the ends of which are vented overboard. Propane is heavier than air. The Refer must be sealed above the waterline when healed and vented overboard. Propane servince to other applicances must be on a separate line that has turn off provisions. You need sensors for leaks and a safe way to clear the bilges just as a boat with a petrol engine needs a bilge blower.
Cooling ventalation. YOu have to get a good air movement over the cooling radiator and out of the boat. Sometimes a small fan and ductwork will help.

Frankly, unless you use the boat a lot and or are not able to get shore power, it is cheaper to add batteries and run the engine a bit extra and build a super 12V refer.
Cheers.
 
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