Cruisair raw water circulation pump

Robski97 said:
Tob,
Im pretty sure all marine condensor coils are made of copper .

Jack,
I expect Gary to paint his impellar flame colors for WOW factor .... He has a standard to live up too...


Rob
Click to expand...

Rob-

No metallurgist, but I believe they use a cupronickel alloy for coils.
It's the alloy that makes the difference. Bronze is copper and tin (OK), brass is copper and zinc (no good).

Copper is not suitable for saltwater use; ever seen a copper through-hull or seacock?

All I know is that the copper fitting on the pump was gone... if I'm wrong here someone correct me...
 
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tobnpr said:
Rob-

No metallurgist, but I believe they use a cupronickel alloy for coils.
It's the alloy that makes the difference. Bronze is copper and tin (OK), brass is copper and zinc (no good).

Copper is not suitable for saltwater use; ever seen a copper through-hull or seacock?

All I know is that the copper fitting on the pump was gone... if I'm wrong here someone correct me...
Click to expand...

The condensing/cooling coils are indeed cupronickle and it lasts for many years. The manifold you have is bronze with cupronickle hose barbs not copper.

You get a problem if you join brass and bronze together as electrolosis eats the zinc out of the brass and the brass falls apart. You see this quite often at a sea strainer where it is connected with brass pipe directly to the pump or a manifold at an overboard discharge. Nylon or plastic/pvc hose barbs or pipe solve this problem.

Brian
http://boatacguy.com
 
Well... I just sissied out and bought a new pump. Got it from Depco for $289.00 complete... not worth the hassle to rebuild this one and have the motor crap out by July (which would be my luck).
 
Damn gary after all that work in my email,,, lol....

See now i learned something . I wasnt aware of cupronickle.

Rob
 
By the time I bought a new impeller and shaft and bushing for the shaft and gasket, I was looking at $45 + shipping. A new head complete instead of rebuilding was $110... but then I have NEVER put oil in this motor and there is a little rust on the outer cover from saltwater hitting it so I just don't want to risk it. $289 it is...

Two things... I now know these little motors need to be oiled a few times a year (the guy at Depco told me that's why the motors go bad and also said he knew it was not in the Cruisair manual but it was in the March instructions that Cruisair does not pass along). Oiling is now on my spring and fall list of to-do's.

The other thing is that my wife has two requirements for a boat: Bathrooms and air conditioning. Boat could be drifting on the open Atlantic with two dead engines and she wouldn't care as long as there is a bathroom and it's cold inside. I'm not messing with the AC going bad.

I may spend the $45 and just oil the old one and clean it up and keep for an emergency spare. Heck... the bridge has a 500 gph pump on it and if that fails, I'll just stick this 1000 gph one on to get me by until I replace the 500 gph one.
 
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Four Suns said:
Well... I just sissied out and bought a new pump. Got it from Depco for $289.00 complete... not worth the hassle to rebuild this one and have the motor crap out by July (which would be my luck).
Click to expand...

This must some of that change I heard about last fall.
 
Four Suns said:
.......Heck... the bridge has a 500 gph pump on it and if that fails, I'll just stick this 1000 gph one on to get me by until I replace the 500 gph one.
Click to expand...

Can the plumbing handle the extra flow and will the A/C unit work as effeciently with double the gph?
 
DOuble the flow would not be great. There alot alot factors but in general doubling the flow is not recommended if no alterations were done. Increasing flow would effect the operation of the units in some manner. ( will they still work ? probably. but it depends again on alot factors. )

Rob
 
osd9 said:
Can the plumbing handle the extra flow and will the A/C unit work as effeciently with double the gph?
Click to expand...

If you look at the performance charts for these pumps (March has a crappy website BTW), they are pretty whimpy. They are very susceptible to head pressure and if you increase the head pressure by about 3x, the flow rate is cut in half. Point is you would not get double the flow... don't know what it would be but adding a bigger centrifugal pump like this does not necessarily increase the flow rate.

If you could increase the flow rate, all that would do is keep the temperature change between the sea water side and condenser side more constant (more water flow would transport the heat being added to the water out of the heat exchanger faster)... it would actually increase the average delta T in the heat exchanger/condenser.... I'll leave to the experts on AC thermodynamic cycles to tell you what that does.

I'm no expert on this by any means. I reviewed the engineering work on the geothermal ground loop system in my house which is essentially a land-based custom "Cruisair" system with closed ground loops instead of raw sea water. The closed ground loops have multiple pumps that kick in and out to control mass flow over the condensers to keep the temp difference at the right level. That's a little different problem as you have a convection problem with the closed loops to disappate the heat in the ground before the fluid returns wheras a boat has essentially an infinite supply of water at a given temperature.

Geothermal is great stuff... I get free hot water (and lots of it) as the system dumps the heat in my hot water tanks and then dumps the rest of the heat out underground where it's a nice 55 degrees or so... Hot tubs, swimming pools, etc. are all "free" to heat with geothermal (plug over) as long as the AC is on in the house.

So... given I have a 500 gph and a 1000 gph pump... I'll carry the 1000 gph as a spare as it'll work on both if one breaks and will work in a pinch just fine until a replacement arrives.

But I did stay at a Holiday Inn Express last night.
 
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26 tons? That's a lot of square footage. General rule of thumb for standard construction residential with 8' ceilings is 500 square ft/ton. That would equate to 13,000 square feet. Figuring for larger window areas and some catherdral ceilings it brings it to about 400 square ft/ton. Still a large footprint. As for the pumps, water cooled systems like chillers and such, as well as geothermal units, use a rule of 3gpm/ton for cooling and 2.5gpm/ton for heating. So you can see how these so called 500gph pumps are derated once the fittings and piping are figured in.
 
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Good to keep the spare, mine dumped while I was on vacation and I had the local marina mechanic replace it the day before I shoved off. 489.00. Ouch, but the wife had cold air.
 
The new pump came at lunch today:

DSC_0001-4.jpg


New one doesn't have the "Cruisair" sticker on it. I guess that sticker costs $130 extra. Going to head to the boat tomorrow and install it...
 
My current pump is, and always has been quite noisy. The noise is worst in the port stateroom. Let me know if this runs quiet - I might just replace it.
 
I have had many boats with the same pump, they are pretty much indestructable. Make sure the magnets are clean, that is about the only thing that will shut those pumps down. Good luck
 
Dang Gary, Wished I had seen the post earlier. I have an extra one of those I'm not using. It is 230 volt also.
 
Does anyone know where to get the water distribution manifold? It's the white manifold on the top of the pump that distributes the raw water to three of the boats reverse cycle units. As you can see, mine is corroding and likely to fail at any moment.
3 port cruiseair manifold.jpg
 
SeaRay48 said:
Does anyone know where to get the water distribution manifold? It's the white manifold on the top of the pump that distributes the raw water to three of the boats reverse cycle units. As you can see, mine is corroding and likely to fail at any moment.View attachment 75699
Click to expand...

I ordered mine direct from the local Dometic distributor. The part number should be in your parts manual for the boat A/C system.
 
SeaRay48 said:
Does anyone know where to get the water distribution manifold? It's the white manifold on the top of the pump that distributes the raw water to three of the boats reverse cycle units. As you can see, mine is corroding and likely to fail at any moment.View attachment 75699
Click to expand...

first thing I would do is relocate it from away fromatop the pump... Add small piece of hose and remount !

Rob
 
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