420DB – Bridge A/C and Heat Installation

[Turtlesboat]

Just because SeaRay does something doesn't mean it's correct or that it couldn't be done a different way.

Doug

That's misguidance? Well I can tell you that i'm in the process of replacing all my Sea Ray installed waste hoses because the ones they installed has a bladder liner in the hose that separates and collapses. It has to be correct because they installed it?

 

[douglee25]

I think you're twisting my words or inferring incorrectly. I'm not going to argue.

I am here to help Alex. Up to this point, my input has been clear, concise, and factual.

Doug

 

[Turtlesboat]

So basically... the under powered Gen, Check. The under powered AC unit, Check. All we have left to check is whether or not a 1" water feed is enough for 3 units. I honestly don't know. Sea Ray initially T'd it off but they did a lot of things that they later questioned or stopped doing. When dealers install a 3rd unit, a lot of them punch another hole in the boat. Why? it's something to question.

 

[Greg]

Originally Posted by douglee25 Just because SeaRay does something doesn't mean it's correct or that it couldn't be done a different way.

That's misguidance? Well I can tell you that i'm in the process of replacing all my Sea Ray installed waste hoses because the ones they installed has a bladder liner in the hose that separates and collapses. It has to be correct because they installed it?

Mike,
I think Doug was agreeing with you. He said just because SeaRay does something it doesn't mean it's correct.

Aside from not upgrading the genny, it seems that Alex is planning to do, for the most part, what SeaRay did. Now while we all agree that that doesn't make it correct, it has worked in many boats.

As long as he is careful running the lines (to avoid abrasion, etc.) and uses quality parts. I don't see a major risk of flooding the salon. The pressure after the balancing valves will not be that great.

As for one intake feeding three AC units, it works in my boat.

 

[Alex F]

No, my concerns for Alex's approach are the one pump/one strainer for cooling. Computing BTU requirement and sizing units boils down to how cool he wants the bridge to get. The sea water approach everyone seems to be taking is a theoretical one based on volume and pressure. I think there are enough variables involved in this type of installation that it wouldn't hurt to examine a successful bridge air installation done by a Sea Ray dealer and warranted by Sea Ray....

Frank,

I could be wrong, but it sounds like the confusion is due to different approach that's taken by different SR dealer installations. As I understand some do this installation by adding dedicated pump while some use existing components and upgrade the pump. When you refer to other 420/44DBs does it mean that those (besides John's which he confirmed had dedicated pump and strainers) that you've seen all of them had separate pumps and strainers for the bridge?

If I recall, I think 500DB has a single pump as well. But, we'll need to clarify from our 500DB owners.

I think it's obvious that having dedicated strainers and a pump will only make the unit function to the pick of it's performance. My logic is that if I can avoid installing the system and minimize drilling wholes under the water line for the price of "theoretically" minor loss of unit's performance, maybe it's worth it. I can only use information I have at hand, but so far I'm comparing two installations (John's and Tim's) and of course the response I got from SR. I'm pretty sure that I've seen Tim's post stating that his pump got upgraded and he ended up with an extra pump as a spare (the original one). We know that John's installation included dedicated strainers and pump. So, by looking at the end result of both systems and taking SR's feedback, all say that their system will knock off about 20*-25* and the owners shouldn't expect to be freezing on the bridge on the hot days. So, it sounds like regardless how you twist it and turn it, in the end you still have relatively the same result. That's why I'm not seeing much advantage of dedicated strainers and pump. In all fairness we might not be comparing apples to apples, b/c Tim has 18K BTU unit and John has 16K BTU Turbo unit. As you can see from my posts I'm leaning toward 24K BTU Ocean Breeze unit, which IMO is a huge step up. This tells me that theoretically, even with the single strainers and pump I should be able to see better results, than a 18K unit installation. Will I get 25*-30* range? I have no idea, but there's no way the system I'm looking to install should perform less than Tim's 18K unit with a single pump.

 

[Alex F]

....As for one intake feeding three AC units, it works in my boat.

Thanks Greg! I thought that's what you had, but didn't want to make the statement without verifying it. This is interesting now. If I understand correctly, 480DBs and 500DBs (there could be many others) have a single pump installation. This means that the pump is perfectly capable to deliver the desired intake and the pressure it creates is acceptable to SR's engineers.

....Aside from not upgrading the genny, it seems that Alex is planning to do, for the most part, what SeaRay did. Now while we all agree that that doesn't make it correct, it has worked in many boats....

That's exactly correct. In addition, I think I'm planning to do it slightly better by adding more powerful A/C unit (24K instead of 18K or 16K). If I recall, 480DBs/500BDs have also 24K A/C unit. If this is correct, than I should expect better results, aside from the fact that I have black canvas top.

 

[Turtlesboat]

maybe it has to do with the water temps and volume? Maybe warmer water boaters need the increased volume due to the higher water temps. Maybe it'll be great in the sound but not so great in the barnegate swamp. No idea.

 

[alnav]

Alex, my 40MY factory-installed pump feeds four AC units, one for the bridge albeit it's a split configuration with the AC in the salon feeding an air handler near the helm. Not sure of the pump capacity but can check it if you're interested.

 

[jg300da]

Sounds like a single pump for multiple units is more prevelant than initially thought.

Alex, don't forget you'll need to add some relay logic to enable/disable that existing pump if you decide to utilize it with the new unit.

 

[Alex F]

Alex, my 40MY factory-installed pump feeds four AC units, one for the bridge albeit it's a split configuration with the AC in the salon feeding an air handler near the helm. Not sure of the pump capacity but can check it if you're interested.

Perfect!!!

Another totally different SR model with single pump for more than two units installation. I'm gaining more and more comfort level and I think my logic is on the right track.

Sounds like a single pump for multiple units is more prevelant than initially thought.....

That's what I'm learning as well.

.......Alex, don't forget you'll need to add some relay logic to enable/disable that existing pump if you decide to utilize it with the new unit.

I was under the impression that all necessary relays are part of the new unit package. Thanks for pointing this out, I'll double check on it.

 

[Greg]

Sounds like a single pump for multiple units is more prevelant than initially thought.

Alex, don't forget you'll need to add some relay logic to enable/disable that existing pump if you decide to utilize it with the new unit.

I think the idea is to swap out the pump. i.e. remove the existing pump and replace it with the 1800 gph pump. Which leads me to mention this: Look at the relay that controls the pump and be sure it can handle the increased load of the larger pump.

I looked at the manual for that pump and it says it can _not_ self-prime, and can not run dry. Is your pump below the waterline? if not, you may want to reconsider the pump choice. If it doesn't prime, you may burn up the impeller. Even if it is below the waterline, you should see if they have something that can run dry. It would be a shame to burn up a pump because you forgot to open the seacock after cleaning the strainer.

Also just so you are clear, my bridge unit does have a separate intake/pump. But the other three units (forward stateroom, guest staterooms, and salon) are all fed from one intake/pump.

The fact that you have one unit at a higher elevation is why I suggested the flow restrictor (balancing valve or whatever you want to call it)

 

[CAMELLA]

My 420DA has one 1,000 gph pump that feeds three units, (2) 16 BTU and (1) 12 BTU. The hose supplying the pump is 1". The cockpit AC (16 BTU) doesn't do much for cooling. Looking for ideas on how to better cool down the cockpit.

 

[Ididntdoit]

I'm gonna thow my $.02 in here.....Your going to have to run a hose to the bridge and buy a new pump anyway - so what is the big deal about buying a strainer and seacock too? Is it just beacause you are afraid to drill a hole in the boat? Based on CAMILLA's response above, I would be doing everything I could to make the system as "high performance" as possible, the first time. I would also look into "insulating" the canvas top - I have seen this in a larger DA, but dont know if its special canvas with the backing attached or somthing that can be added....

 

[Turtlesboat]

Also just so you are clear, my bridge unit does have a separate intake/pump. But the other three units (forward stateroom, guest staterooms, and salon) are all fed from one intake/pump.

wait a minute... is this a disclaimer? didn't you just say your bridge unit was T'd off the same pump? Now it's on a different intake? I wonder why they did that.... AT THE FACTORY. could it be because it makes sense? Maybe there is an issue with an elevated unit in combination with lower units.

 

[Greg]

wait a minute... is this a disclaimer? didn't you just say your bridge unit was T'd off the same pump? Now it's on a different intake? I wonder why they did that.... AT THE FACTORY. could it be because it makes sense? Maybe there is an issue with an elevated unit in combination with lower units.

Nope never said it was T'd off the same pump. The bridge unit has always been on its own pump.

I said one pump/intake feeds three AC units on my boat. The thinking there is that the 1 inch hole provides enough flow for three units (I don't know the total BTU off-hand though). I have four units on my boat.

I agree that there could be an issue with the different elevations, that's what the balancing valves would be for.

 

[Turtlesboat]

So you're recommending a mega pump that will burn up if run dry, to run varying elevated units, attaching flow restrictors on the lower units to build up enough pressure for the upper unit, and a beefed up relay on the single pump... Over a sea cock and strainer feeding the upper unit.? just doing a rough calculation in my head.... 2 x ... add, subtract 3... divided by 8 = NO MONEY SAVINGS AND POTENTIAL ISSUES. But that's just the alarmist in me. everything will be fine.

 

[CAMELLA]

Nope never said it was T'd off the same pump. The bridge unit has always been on its own pump.

I said one pump/intake feeds three AC units on my boat. The thinking there is that the 1 inch hole provides enough flow for three units (I don't know the total BTU off-hand though). I have four units on my boat.

I agree that there could be an issue with the different elevations, that's what the balancing valves would be for.

Does your bridge cool down on hot days? I don't have issues in my cabin but my cockpit AC is useless even with all the canvas left on.

 

[Turtlesboat]

Does your bridge cool down on hot days? I don't have issues in my cabin but my cockpit AC is useless even with all the canvas left on.

there's a formula somewhere in this thread for figuring out the BTU for the square footage you're trying to cool. My guess is you just need a much bigger unit, like double the size you have now.

 

[Greg]

So you're recommending a mega pump that will burn up if run dry

No, I actually recommended against that pump because it could not be run dry.

to run varying elevated units, attaching flow restrictors on the lower units to build up enough pressure for the upper unit

Yes, That is correct, if they are needed. As I said though, I would turn the pump on first after it is all plumbed up and measure the flows to see if there is enough flow at each unit.

and a beefed up relay on the single pump...

Maybe not beefed up, just wanted him to ensure that the current relay can support the new pump.

Over a sea cock and strainer feeding the upper unit.? just doing a rough calculation in my head.... 2 x ... add, subtract 3... divided by 8 = NO MONEY SAVINGS AND POTENTIAL ISSUES. But that's just the alarmist in me. everything will be fine.

Since this is a DIY type of install, I would hate to see something go wrong with drilling a hole in the bottom of the boat. I know I would be nervous about doing that. Especially since so far everything seems to point to the fact that it would not be necessary.

 

[CAMELLA]

there's a formula somewhere in this thread for figuring out the BTU for the square footage you're trying to cool. My guess is you just need a much bigger unit, like double the size you have now.

And that is the whole discussion here, if I get a larger unit I would need a bigger pump with a larger ID hose, more amps which would require a bigger genset, RIGHT?