A/C water line
05-31-2012, 09:48 AM
#1
Registered
Thread Starter
A/C water line
I'm thinking about adding A/C to my boat...
Can I plumb the water pump off of one of the engine's supply lines from the outdrive? Seems way easier like that, no holes to drill in the boat, etc. but I wonder if they will fight each other for water?
If I can't do it this way, where is a good spot for the water line on a Twin Step boat? Part of me wants to put it forward in the cabin area and just be sure the AC is off while I'm running fast. It would make installation WAY easier in my case.
Can I plumb the water pump off of one of the engine's supply lines from the outdrive? Seems way easier like that, no holes to drill in the boat, etc. but I wonder if they will fight each other for water?
If I can't do it this way, where is a good spot for the water line on a Twin Step boat? Part of me wants to put it forward in the cabin area and just be sure the AC is off while I'm running fast. It would make installation WAY easier in my case.
05-31-2012, 12:14 PM
#2
Registered
Join Date: Jul 2009
Location: west of chitown, il
Posts: 461
Likes: 0
Received 0 Likes
on
0 Posts
you def want a seperate water pickup for the ac.. You can do a forward thru hull mount just be sure to put a brass one in with a 1/4 turn seacock installed immediately inboard the fitting, no rubber hose between it and the thru hull fitting. Obviously you want to mount it low enough so it has water at all times when not running. Take wave action into account of the placement. I'm sure someone else will chime in with their thoughts
05-31-2012, 02:01 PM
#3
21 and 42 footers
Platinum Member
You could put it under the cabin step with the "thru hull' on the backside of the step (so that it does not create drag while on plane). I've also seen them put of the transom like this.
05-31-2012, 02:34 PM
#4
Registered
Thread Starter
I want to do it in the cabin step, there is already power there for the bilge pump and the AC will be near by.
I wish I could tell exactly where that step falls in relation to the steps. I don't want to start drilling without knowing.
I wish I could tell exactly where that step falls in relation to the steps. I don't want to start drilling without knowing.
06-01-2012, 05:35 AM
#5
Registered
I have mine pulling water from the drive. I just used the extra hole in the sea strainer and have a shut off valve to close when ac is not in use. Works fine.
For it to work there has to be water flow out of the intake hose from the drive while sitting still. Maybe boats that sit higher in the water at rest can't do this?? AC pumps can't pull water.
For it to work there has to be water flow out of the intake hose from the drive while sitting still. Maybe boats that sit higher in the water at rest can't do this?? AC pumps can't pull water.
Last edited by Shah Mat; 06-01-2012 at 05:44 AM.
06-01-2012, 11:07 AM
#6
Charter Member
You "CAN" run the pump off the main supply line from the drive....but it will depend on what size pump you are using for the system. And what i mean by this is the outdrive can only flow so much water when sitting still....even though most boats have 1-1/4" hose hooked up to the sea water pump coming off the transom...that doesn't mean the water passages in the transom assembly and outdrive are that big. The biggest pump i would say you can run off the stock setup would be the series 3 pump most commonly found as the LC-3CP-MD or the Marine Air P500 or the Cruise Air PM(P)500. This pump will handle most AC units up to about 24k BTU's...they have a 3/4" inlet size.
If you have a bigger AC system you would need the series 5 pumps which require a 1" feed line and the stock lines going through the drive would be too small to feed it properly....in that case you would need a through hull pickup of some sort.
Depending on your setup most have a through hull pickup going to a sea-strainer and then to the engine...just tap off one of the ports if available or install a "T" fitting on the outlet line of the strainer and you should be good to go. If you dont have that setup then allot of boaters install a pickup on the transom of the boat at the lowest point near the hull drain plug, assuming you dont want to run AC while under power. If you did want to have the AC running while underway, then on a stepped hull you would need to install the pickup at the back of the forward most step to supply the pump with clean water. If you mounted it further back in the aerated water then you could cavitate the pump and cause yourself problems. Also....another thing i ran into a while back was a boater was trying to run their AC on an Outerlimits at speeds over 100mph!
What you need to keep in mind, is the faster you go the higher the water pressure will become in the pump and AC system.....so you would need some sot of psi relief valve in those cases. I could probably write a book on this subject but i tried to keep it sort and sweet here.
A little background on me....i work at March Pumps as an engineer and probably close to 75% of the pumps you find on the boats out there with AC systems will be one of ours and i field about 2-3 calls per day from boaters
If you have a bigger AC system you would need the series 5 pumps which require a 1" feed line and the stock lines going through the drive would be too small to feed it properly....in that case you would need a through hull pickup of some sort.
Depending on your setup most have a through hull pickup going to a sea-strainer and then to the engine...just tap off one of the ports if available or install a "T" fitting on the outlet line of the strainer and you should be good to go. If you dont have that setup then allot of boaters install a pickup on the transom of the boat at the lowest point near the hull drain plug, assuming you dont want to run AC while under power. If you did want to have the AC running while underway, then on a stepped hull you would need to install the pickup at the back of the forward most step to supply the pump with clean water. If you mounted it further back in the aerated water then you could cavitate the pump and cause yourself problems. Also....another thing i ran into a while back was a boater was trying to run their AC on an Outerlimits at speeds over 100mph!
What you need to keep in mind, is the faster you go the higher the water pressure will become in the pump and AC system.....so you would need some sot of psi relief valve in those cases. I could probably write a book on this subject but i tried to keep it sort and sweet here.A little background on me....i work at March Pumps as an engineer and probably close to 75% of the pumps you find on the boats out there with AC systems will be one of ours and i field about 2-3 calls per day from boaters
__________________
-Wally
Money can't buy happiness, but it can buy horsepower. And I've never seen a sad person hauling a$$!
-Wally
Money can't buy happiness, but it can buy horsepower. And I've never seen a sad person hauling a$$!
06-05-2012, 12:23 PM
#7
Registered
Thread Starter
You "CAN" run the pump off the main supply line from the drive....but it will depend on what size pump you are using for the system. And what i mean by this is the outdrive can only flow so much water when sitting still....even though most boats have 1-1/4" hose hooked up to the sea water pump coming off the transom...that doesn't mean the water passages in the transom assembly and outdrive are that big. The biggest pump i would say you can run off the stock setup would be the series 3 pump most commonly found as the LC-3CP-MD or the Marine Air P500 or the Cruise Air PM(P)500. This pump will handle most AC units up to about 24k BTU's...they have a 3/4" inlet size.
If you have a bigger AC system you would need the series 5 pumps which require a 1" feed line and the stock lines going through the drive would be too small to feed it properly....in that case you would need a through hull pickup of some sort.
Depending on your setup most have a through hull pickup going to a sea-strainer and then to the engine...just tap off one of the ports if available or install a "T" fitting on the outlet line of the strainer and you should be good to go. If you dont have that setup then allot of boaters install a pickup on the transom of the boat at the lowest point near the hull drain plug, assuming you dont want to run AC while under power. If you did want to have the AC running while underway, then on a stepped hull you would need to install the pickup at the back of the forward most step to supply the pump with clean water. If you mounted it further back in the aerated water then you could cavitate the pump and cause yourself problems. Also....another thing i ran into a while back was a boater was trying to run their AC on an Outerlimits at speeds over 100mph! What you need to keep in mind, is the faster you go the higher the water pressure will become in the pump and AC system.....so you would need some sot of psi relief valve in those cases. I could probably write a book on this subject but i tried to keep it sort and sweet here.
A little background on me....i work at March Pumps as an engineer and probably close to 75% of the pumps you find on the boats out there with AC systems will be one of ours and i field about 2-3 calls per day from boaters
If you have a bigger AC system you would need the series 5 pumps which require a 1" feed line and the stock lines going through the drive would be too small to feed it properly....in that case you would need a through hull pickup of some sort.
Depending on your setup most have a through hull pickup going to a sea-strainer and then to the engine...just tap off one of the ports if available or install a "T" fitting on the outlet line of the strainer and you should be good to go. If you dont have that setup then allot of boaters install a pickup on the transom of the boat at the lowest point near the hull drain plug, assuming you dont want to run AC while under power. If you did want to have the AC running while underway, then on a stepped hull you would need to install the pickup at the back of the forward most step to supply the pump with clean water. If you mounted it further back in the aerated water then you could cavitate the pump and cause yourself problems. Also....another thing i ran into a while back was a boater was trying to run their AC on an Outerlimits at speeds over 100mph!
What you need to keep in mind, is the faster you go the higher the water pressure will become in the pump and AC system.....so you would need some sot of psi relief valve in those cases. I could probably write a book on this subject but i tried to keep it sort and sweet here.A little background on me....i work at March Pumps as an engineer and probably close to 75% of the pumps you find on the boats out there with AC systems will be one of ours and i field about 2-3 calls per day from boaters
