AC Pump Trips Main Breaker

Having a single pump simplifies the system and results in only one strainer and one sea cock/thru hull

If with good access replacing the pump with a matching spare is a 30 minute job.

if you really want flick of a switch redundancy, then you can add a second pump with a set of valves and a selector switch.

I have a single pump feeding both chillers on my personal 53. On the 110 run, we have two pumps for the 3 chillers, of the same thru hull and strainer with selection switch and valves.

All comes down to preference and space available

In terms of redundancy, it's actually the other way round: in your setup, if one pump fail, you lose whatever half of the boat that chiller unit is serving.
As opposed to that, if the system is designed with just one large, multi-compressor chiller (and I've seen up to 4 compressor in a single unit, rated for 300k BTU), by definition there's just one inlet/outlet, BUT it's normally installed with at least two switchable and fully redundant raw water pumps.
In turn, this means that if you lose one of them, you lose nothing, anywhere onboard.

Aha, I see.
I assumed that the only reason for two separate chillers was to place them in different parts of the boats, each connected to its own loop.
If they are placed together and connected to a single loop, I honestly struggle to see the point, when one chiller with two compressors would be simpler and equally redundant (if installed as I previously said).
Was your installation possibly meant to be able to run just one chiller if and when dock power is limited?

Having a single chiller with two compressor is nowhere as redundant since they will be sharing a number of components incl coils, sensors, controls, heat exchanger etc.

The two chillers on my personal 53 are both connected to the chiller water loop. One of them is set to go on and off at slightly higher temps so it only comes on when needed. From mid October thru May, I usually run only one chiller.

same with the 3 chillers on the 116 I run. In summer and daytime all three will be running but at night or come October, two and sometimes one will be enough.

if one fails in summer the boat will not be meat locker cold but still be comfortable enough

Same here. I have two fives in sequence. One is set to fire at 54 and shut down at 46. The second is set to fire at 57 and shut down at 49. I think if I had it to do again I might have split the first into a two follow day a three along with the second five. The wear would be on the two as so many cycles run just to cool the loop, and the sacrificial unit would therefore be a smaller size and cost. The regular power draw would be somewhat less as well on average.

True, in principle. But in practice, I never heard of anything but a compressor failing, in a chiller unit.
And one faulty compressor has precisely the same consequences if installed in one of two single compressor chillers, or if it's in a single twin compressors chiller.

The series setup shares a glycol loop pump for the chiller loop. They share a raw water cooling pump that feeds multiple coils. But everything else is unique to the individual chiller.

In the last couple of years I have had issues with chilled loop flow switches on two of our Cruisair 3 chillers on the 116. Also had a bad low pressure switch. Minor inconvenience and guests didn’t even notice. And also has a bad frequency drive on one them…

the Achilles heel on that cruisair system is that all 3 chillers are controlled by a single electronic controller… if that fails, it’s game over .

The two chiller system on my boat has very simple of the shelf relays and temp controls, fully independent. I can probably order a temp controller and get it the next day if that fails.

Maybe this may help Mapism;
Having managed just a few chilled boats in North Florida, a single water loop thru the boat services all the interior volume. This closed loop driven by a single pump. A back up pump here could be an option. I recall a Marlow had one, years later, never used.
One complete chiller could service this loop. For those really hot days, a second complete chiller was used to get and keep that single water loop cold.
Similar to a DX system, you are blowing cool air AND removing heat as the system works. Just like a DX R**(*) system.
Each cabin has its own cabin operator control and its own controlled bypass valve (cold to colder).

Some boats (as Pascal's 116) has a third complete chiller available to really super cool this loop. Lots of interior air, in the sun, in hot ocean water, many hot bodies bouncing about .
Keep in mind, a heck of a lot of heat coming back from the boats interior to re-cool at the chillers.

I remember working with a surveyor on one boat; With a IR gun and hot air gun, went from cabin to cabin, heating up the air temp sensor (just like on a DX system), watching the by-pass servo operate and watching the out air temp go up & down.
Now , imagine for wimps like me, Some of these air handlers can have electric heaters in them. The rest of the boat can be chilled to some insane level, the cabin controller will close the chilled water servo and enable the electric heater. Ahhh.

For simplicity, all chillers were always cooled in parallel with a single sea water pump. Just like multi DX systems.
Having a second raw water pump plumbed in (stand-by ready) by enabling a valve (or two) and flipping a electrical switch is an easy back-up option.

If I only knew better 25 years ago, I would have a chilled system in our Bert.

Guys, I fully understand the principle.
But a twin compressors chiller works exactly in the same way as two single compressor chillers, for any given total capacity.
The Condaria system in my boat has a single chiller with two compressors, but they very rarely run together, aside from when the systen is started and the coolant in the loop is rather warm.
In this condition, with both compressors running, the whole loop is cooled faster.
But once the preset temperature is reached, both compressors cycle on and off automatically, and almost never run in parallel anymore.
Besides, as I said, I've seen single chillers with 4 compressors and a total capacity of 300 thousands BTUs, which is superyacht territory.

The point which Pascal raised is that two completely separate chillers are better for redundancy compared to twin compressors single chillers, and I did say literally that it's "true, in princple".
Where our experiences differ is that I never heard of any faults with these Condaria multi-compressor chillers, aside from the odd compressor failure.
Which doesn't stop the chiller to keep working with the other compressor(s).
That's the reason why I said that in practice the level of redundancy is comparable, in both alternatives.

Now, if I understood what Pascal is saying, he did experience problems with some multi-compressor chillers related to something else than the compressors, and if so, I have no reason to doubt it.
Every type of system has its peculiarities/weaknesses/strengths, I guess!

You have 2 compressors on one condenser??
Brother, not to throw any negative waves your way, but that is messed up, even by swamp standards.
Just to save 6 inches of copper and 2 feet of hose??

So when that one condenser fails, all is down for repairs??

I don’t like those electric valves Cruisair uses for the chilled water to bypass the air handler. It s just another point of failure and yes I have had one fail.

on the flagship air handlers the chilled water runs all the time thru the AHs without the blower running. Again very simple. And the AH controls have three components. A transformer to step ten voltage down, one relay and an off the shelf thermostat. Each available for under $40 on Amazon . If I want I could even splurge on fancy WiFi enabled Tstat.

yes the Cruisair AHs on the 116 have heating elements. Never used them and I m sure that if we had to use them due climate change they s be dusty and smelly…

btw, I was kind of brainstorming the other day about I would do in a few years if we do move with the 53 to Tennessee. No reverse cycle…. I wondered if I could just out in a couple of 20 gallons water heaters on the loop and generate enough heat. Can’t see why it wouldn’t work. Am I nuts ?

Rydlyme biodegradable descaler

Barnacle Buster is also biodegradable.
BB's ad also states safe in marine cooling systems.
I and my AC vendors use it a lot.