AC pump wiring

[Maynard Rupp]

Our Hat now lives in Miami all year. We run one AC unit constantly all summer. We have to clean the strainer weekly and completly disassemble the strainer monthly to get all the growth out of the assembly. I have always wondered why Hatteras chose to run the cooling water pump all the time when AC is on. The Cruiseair manual says you can chose to power this pump with the red or purple wire. The red wire is hot anytime even when the "start" posiion is selected. The purple wire is hot only whe the thermostat turns the compressor on. I called cruiseair and the tech said that there is no reason to run the pump unless one or more compressor is running. I have moved the pumps power wire for each unit to the purple wire. The entire system seems happy with this change. The tech. said that they used to keep the pump running all the time but that policy hasen't been used in 30 years. We hope that change will eliminate the need for constant attention of that pump's strainer. Can anyone here find a reason to keep that pump running all the time?

 

[MikeP]

Maynard,

Our oem a/c seawater pump only engaged when a compressor was actually operating. I thought that was the whole purpose of the triggers. If no compressor was called for, the seawater pump shut off even though the air handler blowers ran constantly. I wonder if your system is completely original or is it possible a PO wired it up to run the seawater pump constantly? Or maybe it was just set up differently on our 1980 53MY.

I have since replaced the original controls with the coastal climate digital types but they are set the same way - the seawater pump only comes on when a compresser is engaged but the blowers run constantly (if you select them to do so, which is an option with the digital controls.) There is no issue at all with doing it this way.

 

[eze2bme]

The last time I had my Cruisair units serviced I had the technician change the wiring so that the pump only cuts on when one of the compressors is running. As I recall all that he did was to switch one wire from one terminal to another.

 

[Pascal]

indeed, it's better to have the pump run only when a compressor kicks in... i didn't know you could wire it that way directly from the units, i thought you needed a relay box.

that shoudl extend your strainer cleaning to 3 to 4 weeks, expecially in winter when compressor dont' run as much.

I almost never bother disassembling the strainers, i just pull and clean the baskets. Been doing it that way for a very long time no issues.

 

[Canuck Dennis]

Am curious about this also, as I run my reverse cycle in the PNW all winter, my pump guy says that like all mechanical/electrical stuff, they have a cycle life also, like the lite bulb has longer life if left on, so, what's better, more cycling of the pump or less cycling?

 

[MikeP]

less cycling - a motor does not suffer from the same overload "strain" that a light bulb does.

 

[Pascal]

and brushes, bearings get worn...

that said, it is a good idea to make sure the pump run at least every couple of week.

if i dont' use my air for a few weeks in winter, the stupidly expensive suposedly best available Cruis Air pump freeze... i have to bang on it to get it to start.

 

[Jaxfishgyd]

I KNEW there had to be a way to rewire those... Make zero sense for the pump to run 24/7.

The one A/C company I use to us stated I could NOT put digital controls on my units. But have had several people at my marina do so without any problems (they did theirs several years ago now).

Change red to purple.... Sounds almost too easy...

Our AC strainers need to be cleaned in the summertime ranges from every 4 days (2005) to every 3 weeks (2008) depending on the water conditions..

 

[krush]

and brushes, bearings get worn...

Most likely doesn't have brushes---since it's like, you know, an AC motor. There are brushed AC motors, but they are "universal"

 

[REBrueckner]

No reason at all to leave your A/C water pump running full time...that was just a poor design choice many years ago....I,too, had heard digital controls were required to eliminate the excess running and now I know why that never made much sense.....

 

[MikeP]

Well as I said, our 1980 53MY's oem ac system sea water pump only cycled when a compressor came on. So obviously at some point Hatt must have changed the design to use the trigger system that allowed any individual compressor to turn on the sea water pump if needed while the air handler blower continued to run as long as the ac/heat was "on.". Wonder when that change was made?

 

[rwetherington]

I designed A/C ystems for Hatteras for many years and I can tell you that none of the New Bern Models had A/C Pumps that ran all the time. The trigger in the systems aloud for the pump to turn off if no compressor was running. There is no reason to run a pump if the compressor is not calling for water to cool it. There are A/C systems on some of the Hatteras that do not have a trigger but that system is a daises chain system and will also turn the pump off when the compressors are not running. The reason that your discharge water for your A/C system is above water line is so that you can see the water running so that you know that the pump is running. If you look at the new Hatteras they are below water line so that you do not have to here the water running at night.

 

[Pascal]

on my early 53, AC is discharged in the port ER seachest. you can see the flow at the water line, but no noise... a big plus!

I've seen boats that shoot the water a couple of feet above waterline, you dont' want these guys as neighbors in winter if you want to enjoy a cool breeze!

 

[SKYCHENEY]

I've seen boats that shoot the water a couple of feet above waterline, you dont' want these guys as neighbors in winter if you want to enjoy a cool breeze!

The Admiral gets a little upset if she is enjoying a nice sunset on the back deck and the neighbors boat is continually "peeing" out the side. It's usally a Sea Ray. Go figure.

 

[stormchaser]

Mine also stayed on all the time. Annapolis CruisAir assured me it was not supposed to and ti was likely a programming or wiring problem that would be corrected when i swap out the air handlers, power box, and controls...which they jsut finished today...so will test and see tomorrow. I'll report back.

 

[Maynard Rupp]

Maynard,

Our oem a/c seawater pump only engaged when a compressor was actually operating. I thought that was the whole purpose of the triggers. If no compressor was called for, the seawater pump shut off even though the air handler blowers ran constantly. I wonder if your system is completely original or is it possible a PO wired it up to run the seawater pump constantly? Or maybe it was just set up differently on our 1980 53MY.

I have since replaced the original controls with the coastal climate digital types but they are set the same way - the seawater pump only comes on when a compresser is engaged but the blowers run constantly (if you select them to do so, which is an option with the digital controls.) There is no issue at all with doing it this way.

Nope Mike..I checked my original Hatteras wiring prints and the pump is wired to the red, hot all the time, wire. My triggers are just going along for the ride.

 

[Maynard Rupp]

I designed A/C ystems for Hatteras for many years and I can tell you that none of the New Bern Models had A/C Pumps that ran all the time. The trigger in the systems aloud for the pump to turn off if no compressor was running. There is no reason to run a pump if the compressor is not calling for water to cool it. There are A/C systems on some of the Hatteras that do not have a trigger but that system is a daises chain system and will also turn the pump off when the compressors are not running. The reason that your discharge water for your A/C system is above water line is so that you can see the water running so that you know that the pump is running. If you look at the new Hatteras they are below water line so that you do not have to here the water running at night.

Roger, I am looking at my original drawing for the AC wiring on our 1986 36C. It clearly shows the pump power wire on the red wire terminal, not the purple. The red wire is hot anytime that either start or run is selected. The purple wire, (which I now hooked it to), is powered only when the thermostat powers up the compressor. I do have the relay box with trigger for each of the compressors.

 

[Angela]

Maynard, sometime when you're on the dock and have a few minutes, could you stop by and show me how to switch those wires in my boxes? My Cruisair tech (that company is now banned from my boat) told me that it was impossible to rewire the AC pump to cycle on and off with the compressor. I knew all of them were clueless, and I've gone through several AC techs since then. That's a soapbox I won't climb up on right now.

My lower level cycles the pump, but my salon and PH units run it continuously. I just KNOW there is a way to fix that.

 

[saltshaker]

Maynard,
My '74 46C was wired the same as yours. My wiring diagram also showed the same as yours does. I switched it out years ago. Worked fine with the 3 knob controls. Last year I had the last of my original compressors fail. Changed both units to digital panels at the same time. Huge improvement. Much better temp control.

 

[GJH]

Angela here is the name and number of my A/C and plumbing guy. Maybe you will cycle through him too, but he has always done right by me:

Jorge Sosa

Chico's Marine

954 260 7840

Just tell him your issue over the phone. He does a fair amount of on board engineer type work on boats going to and from South and Central America, so availability can be sketchy. But he shows up and works quick and doesn't do stuff for the sake of doing it. Nice guy too.