two fridge boxes, one compressor? dual unit

[Silver_Surfer]

On my Baltic 43 i have the two-fridge box galley set up and trying to figure out how it was originally run. currently the box fwd of the stove is active and run by a nova cool unit that resides under the nav station chair. the other cooler box, aft of the stove has the coolant lines cut and above the counter is a original fridge control panel with Baltic Yachts script on it. The abandoned copper coolant lines run into the same compartment with the active nova cool unit, and there are 4 copper lines. I was thinking they had one compressor running both coolers. I called nova cool and they don't daisy chain cold plates but said you need two units. Maybe another mfg. can do this?

[Bowdrie]

Yes, trying to run boxes with two different temps from one 12V cap-tube unit is generally a lost cause.
Cap-tube units lack the ability to control the flow on the high side and they have no provision to store excess refrigerant that's returned from the higher temp box.
You need two units.
Were the compressor/condensing unit a powerful AC unit using TXVs, a receiver, and with evaporators hooked in parallel then there are several methods available for independent control of each box.

[Silver_Surfer]

what if you don't having them both operate at the same temp? i mean if they're cold that's fine with me, i don't think i need a freezer. could that work?

[Bowdrie]

A technician would use one high side 1/4" line to leave the condensing unit.
That line would feed a distribution block, (not a simple Tee fitting,) with two outlets, each outlet line would feed a cap-tube on each evaporator.
The suction lines would be teed together near the compressor.
The existing cap-tubes would probably be changed for smaller capacity ones, (kinda like resistors in parallel,) as now each evaporator will only get 1/2 the flow that it previously received.
All that work by a tech will be expensive and you'll still have all your eggs in one basket, the unit fails and you got nothing in either box.
Easier to get the second condensing unit, hook it up, do the vacuum/recharge process and be much happier with two independent systems that can operate at whatever temp you desire.
Those 12V units, no matter what the manufacturer, (or anyone on the forum,) claims, they are still weak/small capacity devices that are not tolerant of high condensing temps nor small amounts of overcharge/undercharge, or voltage issues.
Even in the best boxes of small capacity with lots of insulation and well-sealed lids they still run about a 50% duty cycle.

[RaymondR]

"Easier to get the second condensing unit, hook it up, do the vacuum/recharge process and be much happier with two independent systems that can operate at whatever temp you desire."



Way to go. Cheapest to implement and you get redundancy and if you can stand the amp draw could run one as fridge and one as freezer.

[Silver_Surfer]

ok, yeah just looking at how this was set up before. i called sea frost and asked tech cleave about my original set up and he not sure but suggests a new set up with two separate units. just have to figure out where to put the second unit. thanks for the replies and suggestions.