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02-04-2017, 09:05 PM
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#1
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Veteran Member
City: San Diego
Vessel Name: Fishbone
Vessel Model: 1990 Nova/ sedan
Join Date: Jan 2014
Posts: 38
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A/C heat exchanger operation
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
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02-05-2017, 12:08 AM
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#2
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Guru
City: Port Ludlow
Vessel Name: Fiddler
Vessel Model: DeFever 46
Join Date: Oct 2012
Posts: 703
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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.
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02-05-2017, 06:38 AM
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#3
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Valued Technical Contributor
City: Litchfield, Ct
Join Date: Aug 2012
Posts: 6,785
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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
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02-05-2017, 06:45 AM
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#4
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Guru
City: Annapolis
Vessel Name: Ranger
Vessel Model: 58' Sedan Bridge
Join Date: Aug 2013
Posts: 7,088
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Quote:
Originally Posted by 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.
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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
__________________
Chesapeake Bay, USA
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02-05-2017, 07:05 AM
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#5
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Senior Member
City: Northern Chesapeake
Vessel Model: Carver 440, 6CTA8.3's
Join Date: Oct 2007
Posts: 424
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..... And electric mattress cover, not blanket.
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02-05-2017, 07:10 AM
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#6
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Guru
City: Ft Pierce
Vessel Name: Sold
Vessel Model: Was an Albin/PSN 40
Join Date: Oct 2011
Posts: 28,149
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Quote:
Originally Posted by bluebyu
..... And electric mattress cover, not blanket.
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.....love mine, never liked the electric blankets.
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02-05-2017, 08:55 AM
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#7
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Veteran Member
City: San Diego
Vessel Name: Fishbone
Vessel Model: 1990 Nova/ sedan
Join Date: Jan 2014
Posts: 38
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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
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02-05-2017, 09:27 AM
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#8
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Technical Guru
City: Wilmington, NC
Vessel Name: Louisa
Vessel Model: Custom Built 38
Join Date: Jan 2014
Posts: 6,194
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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.
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02-05-2017, 01:39 PM
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#10
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Guru
City: Inside Passage Summer/Columbia River Winter
Vessel Name: Alaskan Sea-Duction
Vessel Model: 1988 M/Y Camargue YachtFisher
Join Date: Jul 2012
Posts: 8,050
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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.
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