Now that I understand “why” Hatteras grossly oversized my AC pump (because there wasn’t anything available between the 1500 and 3000 gph back then, and thank you for answering that question on the HOF site), I have returned the Series 7 March pump and have the 5.5C pump you recommended waiting for me to pick up from my wholesaler. When I go to install it, I want to take the opportunity to clean up some of my hose routing. It’s a little messy in there since we removed the capacitor bank (I think that thing may have been called a power correction…something), and I now have a large empty space and loose water hoses just lying there. I want to tidy that up and better secure the water hoses like they should be.

Part of this will include making a new “tree branch” on the exit side which is currently made of some metal and it’s rusty. It’s not leaky (yet), but I don’t like it. I want to change this "tree branch" to PVC like the supply side had been done. My question relates to those tree branches since some of our equipment has changed since those were created.

Currently, we have three condensing units (two 24's and one 16). The seawater comes in through one hose and branches off into three separate runs (one to each condensing unit) and then comes back together through a similar manifold where the water exits the boat through a single outlet. Here’s what has changed. We bought a new 24K modulating condensing unit a while back, and its seawater coils consist of two separate rounds of coils with each run having its own inlet/outlet; thus, it takes two incoming/outgoing water lines. The installer merely Y’ed the original single supply to split between them and Y’ed them back at the exit. Is this satisfactory? Or do I need four separate supply lines coming off the main “tree branch”? Of note, the old (non-modulating) 24K unit that runs the galley/salon has a single seawater coil that makes three loops around the unit. The new 24K modulating has two separate coils, but each coil only makes two loops around the unit. The way I see it, the same amount of water is running through both 24K units, but for the modulating unit, only half of the water flow is running through each coil on that modulating unit. The previous modulating units were not coiled like that – they were a single coil. I don’t know why they built this one as a double, but I suspect you do (and I'd enjoy knowing why). It is a CruisAir condensing unit – one they don’t make, except by special order – it’s not the one they show on their website or normally stock. I’m told by the CA regional rep that the only folks who use that particular one are the Hatteras Series I 58MYs and they make up one only when someone asks for it.

What is the proper way to cool these units given these details? If it’s good the way it is, then that’s fine, and I’ll just tidy up my hoses, but if I can make it better and healthier, I don’t mind the extra work to do it right and help increase the life of these machines.

Thank you.

By the way, I need to buy a valve cap for my CA modulating unit – When they installed it, they never put the caps back on (could be lost in my bilge somewhere – I've come across a lot of stuff down there, but not that) and I think it may be something with some sort of importance since the valve has a gasket on it and presumably, the cap helps to seal something. I don't have a part number because the dealer lost the manual and all paperwork on the unit before they even got it to the boat. I asked for it repeatedly, but I never got it. Best I can do now is a photograph and a ruler for measurement. DeWayne tells me it's an oddball valve and cap.

Thank you, Steve. When I make up the new manifolds, I will run individual water lines to each condensing unit's input/output. Cosmetic appearance in my engine room takes a back seat to proper installation. This will also give me an opportunity to run some new water hoses. When they installed the modulating unit, they used pieces of hose and merely barbed them together rather than running a proper length of hose and doing it right (yes, that's right…another particle of that black cloud of air conditioning that follows me and another reason why that particular dealer is not allowed on my boat – that's the level of quality of work they do). That's always bugged me, so I'll take care of that while I'm in there. While I'm at it…I think I'll put in an access port and valve to make a port to easily flush the coils with the acid wash without having to remove any hoses.

Thanks again. Can't wait for the new pump!!

Thanks for mentioning it, but yes, I know not to put the pump where that box was. I have a dedicated, glassed-in pad for that pump to sit on bottom of the bilge floor next to the seacock and sea strainer.

Initially, the dealer installed a RM24C. After nearly year’s worth of constant service calls because the unit would not function properly, they figured out it was the wrong unit and admitted that it would never work right with my equipment. The dealer and the regional rep got into a pissing contest over whose fault it was, all the while I had to wait for them to finish their fight before I could get my problem fixed and have air conditioning again. I got tired of waiting – they had my thousands of dollars and I didn’t have the right equipment and didn’t have reliable cooling. So, I finally contacted the trio of Butch Prince, Louie Swingle and John Barnett, and collectively, they got the ball rolling on getting the right unit for me and agreed to exchange, at no additional charge since I did not make the selection of equipment in the first place, the RM24C for the right one. However, the local dealer then tried to charge me for another unit and all the additional labor to take out the wrong unit and install the right one a second time. I’m told they dug out their old plans and built the WFAH24CM3 which is what was in there originally. That one works in my system. Well, all of that is what they told me, anyway. It's the WFAH24CM3 for which I’m needing a certain valve cap. I’ll still need to take a photo to see if CA has that part available somewhere. It's not the suction/supply valves; of course, they didn’t replace those caps either, but I got some along the way since they were a standard size item.

Yes, I’ve had the unfortunate luck of having a lot of bad service here in Miami on that modulating unit, always seeming to draw the short stick. Miami could benefit from having someone like you around here. Once I met DeWayne, I got him to come out personally and correctly charge that unit – that’s not the 24K unit about which we discussed recently that the tech overcharged. Finally, that modulating system is cooling all of the staterooms adequately and the compressor isn’t hot as a firecracker anymore – I felt it today…it’s perfectly warm. No one who has come on this boat has ever been able to get that one right. I'm very happy that it's done, though.

Post edited 3:50 pm – September 6, 2010 by Angela

I am going to do as you say and split my water hoses into four runs, one for each coil and, in total, I have four coils wrapping around 3 condensing units with one of the 24K’s having dual coils and the other 24K having only a single one. In planning this, I am looking at the math and equipment I will have and have a question about adequately cooling the older 24K condensing unit. The TE-5.5C-MD pump is 30 GPM. If split that four ways through each of the four equally sized hoses and all hoses splitting off and coming back together at the same point, is it fair to say that each hose will be delivering 7.5 GPM (30 ÷ 4)?

So, the dual-coiled 24K unit would be receiving 15 GPM, while only requiring 8.34 GPM for its two tons, but the older single-coiled 24K unit would only be receiving 7.5 GPM of water, yet it requires a minimum of 8.34 GPM, right?

When calculating needed water flow amongst varying sized condensing units, and throw in a dual-coiled one into the mix just for a few more gray hairs, is there some sort of rule of thumb, for instance, that says we should calculate required GPM in favor of the largest, most needy unit in the system which may often result in overkill on the smaller stuff? Seems to me that in an ideal situation, each condensing unit would have its own pump that ideally matches the condensing unit’s need, but when you have, for example (and using extremes here), a 8K sitting next to a 24K, both equally or nearly equally sharing a water pump, the 24K is getting the short end of the stick.

This would seem to me to explain why CA went to dual water coils in the larger unit – so that those units could more equally compete for cooling water with their smaller buddies on the shelf next to them, but I still have one very old 24K unit to cool that is single-coiled. What is your opinion in this regard?

Thanks, Steve. Figure 10 in that pdf confirms my recollection – that the outter most "branches" have more flow than the two inner ones. I remember seeing that illustration somewhere before; I just couldn't readily remember which set was greater and lesser. I'll be sure to plumb the single-coiled unit to one of the outter branches and the two inner ones to the dual-coiled 24K unit, whether it matters or not – it will make me feel better about it. Thanks again.