A/C heat exchanger operation

[Lunasea]

folks,
I did a search but couldn't find it.

my last live aboard had electric box heaters in each space. I am moving on to a new boat that has 2 A/C heat exchangers, and I got to thinking about its use. I live in san diego, with the mild winter I wouldn't expect the heater to come on but a few times during the evening.
so the question is, do you leave the pump on all night to support the heater? that doesn't sound very efficient. are these units suitable for live aboard use, or should I use an electric blanket/ space heater?

thanks

 

[drb1025]

On my reverse cycle units, the thermostat has a setting to have the cooling pump on only when the condensers run. It is a Marine Air/Dometic unit with the Passport thermostat control.

 

[DavidM]

I presume you are talking about a reverse cycle A/C cooing/heating system. Two heat exchangers? Does that mean one compressor and two fan/coil units (a split system) or two compressor units?

If one compressor then the raw water pump will come on when the compressor comes on. With two compressors and one raw water pump serving both, then there is often a relay installed which lets the raw water pump run when one or the other compressor is running.

You should not have to run the raw water pump all night. If so then you need to get a marine electrician to set up the relays.

David

 

[ranger58sb]

On my reverse cycle units, the thermostat has a setting to have the cooling pump on only when the condensers run. It is a Marine Air/Dometic unit with the Passport thermostat control.

Yep, ours is probably similar.... although we have no setting that causes the pump to run all the time.

Two Marine Air ACs, each with its own thermostat (Passport II controls), and one water pump to support both ACs.

Our water pump only runs when the thermostat causes one or the other AC compressors to run.

We DO have a setting to control whether the blower (fan) on each unit runs continuously or only when it's condenser is on. In fact, we vary that, depending on time of year. In mild weather, we cycle the fans when the condensers come on. In July and August, we usually run the fans continuously.

-Chris

 

[bluebyu]

..... And electric mattress cover, not blanket.

 

[psneeld]

..... And electric mattress cover, not blanket.

.....love mine, never liked the electric blankets.

 

[Lunasea]

yes, they are 2 separate units. when we did the sea trial and tested them they were on the whole time. it didn't occur to me that they might have a relay and cycle on and off. something else to look forward to when we take ownership next week.


thanks for the replies

 

[Ski in NC]

San Diego is a perfect place for reverse cycle heat and AC. When you do want heat, they will work fine due to moderate temps. Resistance style heat is necessary when super cold, where rev cyc performance is poor.

 

[FF]

When its cold and the electric on the dock leaves , these are the best way to be able to ignore the temp.



In the AM you can winterize the engine and other systems , while hoping the juice will come on , eventually.




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[Alaskan Sea-Duction]

The water pump (at least on mine) runs when ever the unit is turned on, to include in fan position. When the switch is in run position the compressor cycles on and off. I have two units and one pump.