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Norcold 3way fridge

PostPosted: Tue Jun 09, 2009 9:05 pm
by atkryder
This weekend at a yardsale I bought a brand new 3way fridge that a guy was going to use for a horse trailer conversion.
Like i said is is brand new and i picked it up for $100.
I havent started my build yet but i am compiling my material for my build.
I know they are naysayers against the installation of one of these in a tear I plan on buildin a 5x12 so i should have plenty of room in the galley.
I need input from those who have sucessfully installed these in their tears!!!
Thanks for all the help and input!!!
Seth

PostPosted: Tue Jun 09, 2009 10:15 pm
by Micro469
A three way fridge being 12 110 and propane? I don't have one, but I'd say go for it. You have three options to keep it cool. I'd say go for it...... :thumbsup:

PostPosted: Tue Jun 09, 2009 11:52 pm
by madjack
Seth, many have talked about it but I know of no one who has done it...for proper operation and VENTING, these units need to be hard mounted to an outside wall which pretty much negates their use on a tear...if you solve the VENTILATION problems it will work and we will wanna see LOTSSA pics...........
madjack 8)

PostPosted: Wed Jun 10, 2009 6:14 am
by 48Rob
Seth,

Jack is right about ventilation, and the need to have it back up to an outside wall for access and exhausting.

If you turn it sideways in the galley, the door is in the wrong place...

That said, if there are no coils or wires in the way, you may be able to cut a top access into the fridge and countertop?

Rob

PostPosted: Wed Jun 10, 2009 6:51 am
by JayM
They also require 12v for the control unit/thermostat, and can be pretty picky about low voltage, so allow for that when planning the electrical system if you plan to operate off-the-grid for any length of time.

PostPosted: Wed Jun 10, 2009 6:53 am
by len19070
JayM wrote:They also require 12v for the control unit/thermostat, and can be pretty picky about low voltage, so allow for that when planning the electrical system if you plan to operate off-the-grid for any length of time.


The smaller ones are usually mechanical units and don't need 12 volts for controls, except for the 12volt element which isn't very efficient. They eat batteries rapidly.


I would set it up as a free standing unit. You can take it with you anywhere....even after you sell your tear.

No worries about ventilation, carbon monoxide, open flames, removal for servicing and so on.

That's quite a find for $100.

Happy Trails

Len

PostPosted: Wed Jun 10, 2009 3:48 pm
by atkryder
I really like the idea of a free standing unit!!
Anyone have any thoughts on how to make an enclosure for one of these?
Great idea len!![/u]

PostPosted: Wed Jun 10, 2009 4:42 pm
by chorizon
atkryder wrote:I really like the idea of a free standing unit!!
Anyone have any thoughts on how to make an enclosure for one of these?
Great idea len!!


My brain is picked. I have a Dometic like your Norcold just sitting there, waiting to be used/sold/trashed. I'd definitely like to use mine as well. The only real problems I see are:

1) It is bulky in its current state.

2) These things take forever to cool down.

Possible solutions?

1) Attach quick disconnects for the 3-way "power", and build a lightweight frame/stand. Possibly use Coleman 1# canisters for this, if relying on propane? Store in TV while on the road.

2) It would have to begin cooling down the day before your trip, and stay cool throughout, therefore necessitating it be hooked up to some kind of power the whole time. If it was in the back of my truck, no big deal. If it was in our car (in the trunk) I'd be worried to run it off of propane, but think 12V would be do-able (if it'd fit in the trunk of my car)

Hmmm, in the back of my truck the propane pilot wouldn't stay lit. I think there would be an easy way to do this, though.

These frig's are real convenient hard mounted in your average travel trailer. Just throw your stuff in and take off. In a portable situation, the only thing you'd be saving really is the purchasing of ice every so often. You still have to lug the thing around. Excuse me whilst pondering... :thinking:

PostPosted: Wed Jun 10, 2009 5:13 pm
by len19070
atkryder wrote:I really like the idea of a free standing unit!!
Anyone have any thoughts on how to make an enclosure for one of these?
Great idea len!![/u]


The first thing you do is mount 2 big handles near the top so you can use it.

Then get a small propane regulator and line to fit the LP connector (3/8 flair female) Like for a gas grill...Home Depot item.

Image

And an adapter for 1lb bottles

Image

Then just make a piece of metal (I used Galvanized sheet metal) to cover just the coils in the back. Connected to the side, across the back and then affixed to the other side. The metal should be about 1" away from the back of the coils.

A 1lb bottle will last almost all weekend (it will give out Sunday in the AM sometime).

Or use a larger bottle.

Happy Trails

Len

three way fridge

PostPosted: Wed Jun 10, 2009 9:58 pm
by eamarquardt
I bought a 3 way for my "project" that's moving verrrrry slowly. I've spent some time on the phone with the engineers at Norcold and have learned that they do install them in "blind" applications and use small fans to cool the coils. Contrary to "popular belief" (or conventional compressor systems) you do not want to run the condenser as cool as possible!!!! The gases need to get up to the right temperature to separate so the cycle will function. they told me that the tube on the left side of the top coil should run about 155 to 160f. So, I plan on making some shrouds, try a couple of fan and thermostat combinations and see how much fan capacity it takes to make work. Thermostats are availavle at ww grainger with the needed characteristics. I may use two and "cascade" the fans with the second turning on at a slightly higher temperature than the first. Who knows, at low tmeperatures, convection might be sufficient. If you can keep the coils at optimum temperatures, you may be able to operate the system even more effectively than with convection, as using convection only, you have no control and in my mind it's like running a car engine without a thermostat. There are lots of computer fans that run on 12 volts and draw as little as .25 amps which is practically nothing and you could go over 4 days at 100 duty cycle and not exhaust a typical 100 amp hour battery (that can really only deliver about 50 amp hours) even if two fans were required. Shoot me a pm and we can chat on the telephone. I got a nice fluke temp meter that uses thermocouples (and a lifetime supply of thermocouple wire) at a garage sale for a buck so I can easily measure the temperatures under various conditions.

Hope this helps,

Cheers,

Gus,

You got a bargain and I'll take it off your hands if you decide not to use it.

Re: three way fridge

PostPosted: Wed Jun 10, 2009 10:24 pm
by Trackstriper
eamarquardt wrote: ....The gases need to get up to the right temperature to separate so the cycle will function. they told me that the tube on the left side of the top coil should run about 155 to 160f.......There are lots of computer fans that run on 12 volts and draw as little as .25 amps which is practically nothing and you could go over 4 days at 100 duty cycle and not exhaust a typical 100 amp hour battery (that can really only deliver about 50 amp hours) even if two fans were required....

A variable speed computer fan with a temperature probe might be applicable with enough playing around. Something like this?

http://www.microcenter.com/search/searc ... submit.y=0

I have no idea what the temperature range of operation is. Maybe it could keep the unit in the optimal temperature range.

PostPosted: Thu Jun 11, 2009 6:55 am
by len19070
len19070 wrote:
Then just make a piece of metal (I used Galvanized sheet metal) to cover just the coils in the back. Connected to the side, across the back and then affixed to the other side. The metal should be about 1" away from the back of the coils.

Len


Fans are only needed if venting is a Problem, and even at that only on the larger units.

A free standing Ref is NOT a "blind application" and will not have a venting problem or need fans.

K.I.S.

Happy Trails

Len

PostPosted: Thu Jun 11, 2009 4:34 pm
by atkryder
What do you mean by "Blind Application"? I like the the idea of a free standing unit but am not closed off to the idea of perminent installation if proper venting and accesability can be achieved.

PostPosted: Thu Jun 11, 2009 5:36 pm
by Trackstriper
I'm not sure what Gus meant by "blind" but I would assume that the conventional air opening sizes and locations were not used. Just guessing here, but I wouldn't think that there would be all that much airflow created by convection from the standard bottom vent/access up through the upper vent. Convection will move the air silently and without mechanical failure, but I don't see it moving huge quantities of air in this case, especially considering the relatively short "chimney", there's not a lot of height difference between the two vents.

Now suppose someone fed air with a fan/blower to the backside of the unit, assuming it was correctly baffled. Consider two fans in a "push-pull" configuration....one pushing air in at the bottom, the other one pulling air out at the top. That would give redundancy in the event of a fan failure, either one by itself would move nearly as much air as both fans working together. Especially if you used a small blower which will operate at considerably higher static pressures than a simple bladed fan. Maybe something like this (sorry about the long URL):

http://cgi.ebay.com/2-Pcs-Brushless-DC- ... .m20.l1116

It would take some thinking about how to do this, but I would think the vent openings could be quite small, a couple of square inches each. It's not like you would be venting a furnace. Vent air could be brought in from under the tear and exhausted out a small side vent so that the fridge would work with the hatch closed. An over-temperature switch might be hooked up with the thermocouple....

Getting access to light the pilot might be the tricky part. Possibly from under the trailer or from inside the cabin with a serious hatch, or maybe have the whole thing on slides and allow it to come rearward a foot so you could get behind it.

I guess what I'm thinking is that there are enough really smart folks on this forum to be able to figure out how to do this safely without burning down a teardrop.

PostPosted: Thu Jun 11, 2009 7:19 pm
by len19070
atkryder wrote:What do you mean by "Blind Application"? I like the the idea of a free standing unit but am not closed off to the idea of perminent installation if proper venting and accesability can be achieved.


A "Blind Application" is a ref just stuck in a slot with no conventional access to the rear of the ref or conventional venting.

Which is very important.

It means an alternative air intake, heat considerations and a difficulty (and probably an absence) to regular Maintenance.

How much "hands on"experience do you or others have in designing this sort of system? Not internet look up, hands on experience?

ABSORPTION REFRIGERATORS TAKE UP TO MUCH ROOM IN A TEARDROP!

I have built many, many trailers in my past 27 years as an RV Technician. I work on 10 to15 of them a week and the #1 problem is VENTING., designed by professionals :lol:

Any 3 way Ref will work free standing, as soon as you put it into a hole things change.

I have long ago abandon the idea of effectively mounting a 3 way Ref in a Teardrop.

NOT that it can't be done....It just isn't a practical thing to do.

This is not a operation you should "see how it works out" If not done Properly is very very dangerous.

If someone "Thinks this will work", "because they heard it from a guy" or "Try this, I read it somewhere" Chances are they have never done it.

Let them try it first.

Carbon monoxide or Fire can take the fun right out of Camping.

Happy Trails

Len