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Replacing ac/dc frig with 3 way

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07-10-2006, 02:26 PM
Dewey
Replacing ac/dc frig with 3 way
What would be involved in replacing a 2 way with a 3 way refrigerator -- or what would be a better solution for expected weekends of boondocking?
It would appear that 2 factors are involved -- getting LP to the unit and dealing with venting. Any suggestions?
07-10-2006, 02:32 PM
bill h
The standard terminology is that a 2 way fridge has propane and 110 volt heating sources. A three way adds a 12 volt heating element. Installation is the same except for the necessity of a heavy 12 volt wire.

The advantage of a 3 way is that you can use the alternator or solar to power the fridge while driving instead of having your propane on.


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84 30T PeeThirty-Something, 502 powered
07-10-2006, 02:42 PM
Dewey
Thanks, Bill, for the clarification. I am considering a unit that has the original (as I understand it) AC/DC -- no propane. I desire to go 3 way and add propane. Thoughts?
07-10-2006, 02:48 PM
Danny Z
My experience of camping at the track for a 4 day weekend is that the 2 way Dometic uses a trickle of propane. At the risk of raising a new issue, I don't turn off the LP when on the road, mostly to run the fridge, but I firmly believe in a competant GAS CHECK at least yearly. Our local RV dealer will not allow any kind of unit to go out without one. The lack of a 12 volt alternative has never been a problem, although it might be a bonus in certain conditions.


79 Barth Classic
07-10-2006, 02:56 PM
bill h
quote:
Originally posted by Dewey:
Thanks, Bill, for the clarification. I am considering a unit that has the original (as I understand it) AC/DC -- no propane. I desire to go 3 way and add propane. Thoughts?


Hmmmm..that is unusual.

However, Barth did make some all-electric coaches for those who always plugged in. If it really does have an electric-only fridge, I guess it would just be a matter of measuring. Installing a roof vent is no big deal. There might even be a vent there already, as electric fridges have to get rid of heat, too.


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84 30T PeeThirty-Something, 502 powered
07-10-2006, 03:02 PM
Dewey
My question posed to the seller:

Does it have AC/DC or Gas/Electric refrigerator?

His response:

It has ac/dc refer
07-10-2006, 03:05 PM
Dave Bowers
The huge majority of RV'ers leave their propane on in transit. I had this discussion with some folks on another website some time ago and I did some research by going to Dometic and asking how many fires there have been by leaving the propane on. The guy I talked to had been there some 20+ years and he had never heard of it. If I were buying a new frig i would go with 2 way.


07-10-2006, 07:03 PM
Bill N.Y.
quote:
Originally posted by bill h:
quote:
Originally posted by Dewey:
Thanks, Bill, for the clarification. I am considering a unit that has the original (as I understand it) AC/DC -- no propane. I desire to go 3 way and add propane. Thoughts?


Hmmmm..that is unusual.
This is how my Barth came.

Bill N.Y.
07-10-2006, 07:54 PM
Rusty
Conrad Bennett, who owned my Breakaway before I did, added a 750W (a bit of overkill) inverter, which powers the reefer through a relay (so that when 120V power is connected, the inverter's disconnected).


Rusty


MilSpec AMG 6.5L TD 230HP; built-to-order by Peninsular Engines:  Hi-pop injectors, gear-driven camshaft, non-waste-gated, high-output turbo, 18:1 pistons.  Fuel economy increased by 15-20%, power, WOW!"StaRV II"

'94 28' Breakaway: MilSpec AMG 6.5L TD 230HP

Nelson and Chester, not-spoiled Golden Retrievers

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In either case the idea is quite staggering.
- Arthur C. Clarke

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07-13-2006, 01:36 PM
REGLOVER
I have a 1976 Barth with the original Norcold refer model DE 728 which is a dual voltage refrigerator , 12 volt DC and 117voltAC
, the unit has an ac compressor that operates off 23 volts AC.
It doesn't have to be level to work properly. We love it I wish they still manufactured them.

Ralph
PS if any of you guys have any parts for these old units I will purchase the old power supply for the model 728 from you.


Ralph Glover
1976 27' Barth
P-30 454
1998 Tracker Toad
07-13-2006, 02:06 PM
Dewey
Ralph --
How do you deal with boondocking with the frig -- doesn't it drain the batteries pretty quickly? I had a sailboat with a very efficient refrigerator, but two 8D batteries couldn't keep it going all that long.
Dave
07-13-2006, 03:00 PM
REGLOVER
Dave we have never went overtwo days without pluggling into 110 volts, so I.m not sure how long it would last on your batt.
the compressor on my old unit is rated at 60 watts.

Ralph


Ralph Glover
1976 27' Barth
P-30 454
1998 Tracker Toad
07-13-2006, 04:08 PM
Dave Bowers
Dewey, your propane is an excellent way of cooling the frig down. In fact, it seems to me that when we have it on propane it cools faster and stays colder than on 120V.

Plus the few times that you use your generator for the TV, microwave or what ever it will automatically default to the 120v from the gas. Thereby, saving gas. We hardly us any gas anyway, choosing to barbecue or use the micro-conv. more often.


07-13-2006, 04:40 PM
bill h
quote:
Originally posted by Dave Bowers:
... when we have it on propane it cools faster and stays colder than on 120V.



That has always been the case with our RV fridges, too.


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84 30T PeeThirty-Something, 502 powered
07-13-2006, 06:58 PM
olroy
Indeed, the manuals for RV absorption-type fridges tell you to cool the box down with propane. The electrical element, whether AC or DC will usually do no more than hold the temperature thus achieved.

Years ago, we left a 31' travel trailer year- around in Indio, CA. We couldn't cool the box with electricity when we returned in the Fall, but once cooled with propane, electricity would maintain the temp.

Ralph's older fridge is not cooled by absorption, it has a compressor. That's also why it works off-level. The refrigerant, no doubt Freon, is pumped mechanically through the system.

The refrigerant in absorption-type fridges is anhydrous ammonia. That's why your fridge stinks when it quits. It works by heat, plus gravity, & the gravity flow requires the box be nearly level.

Do a Google search for absorption refrigeration cycle for a detailed explanation.