Upgrading freshwater pump for more pressure...

Skuza

Well-Known Member
Nov 1, 2006
1,453
Lake St Clair, MI
Boat Info
400 Sundancer
Engines
7.4L Horizons
Has anyone upgraded the FW pump on their boat to a higher GPH? I have been thinking about this for the past couple years and wonder if the factory quick connect plumbing can take it? It just seems like a little more GPH would do the trick. I don't recall what the factory pumps rating is. I do recall a 460 having two pumps. Was it plumbed so that each pump fed a certain area on the boat?
 
There is a difference between volume and pressure. Your pump has enough pressure, but when you open a faucet, more water flows than the pump can replace, so it appears you have low pressure. Adding a second pump will do more than anything to help your problem.

Take a look at the plumbing diagram on either a 450DA or a 460DA and you can figure out the best lines to tap into.....expect to run some new tubing since you will want the pump on the bulkhead near pump #1, but your source and outlet may need to be forward in the boat a ways. I have the plumbing diagram for 450's if its not available on the Sea Ray/service/parts site.
 
I'm wondering if I installed two pumps what would be the proper setup? Would they be hooked up in parallel? Have the supply line split into two feeding the dual pumps then tap back into the one supply line? Or would it be better to have two seperate supply lines to each pump from the tank and then after the pump feed back into the one supply line? OR should the fwd bathroom be cut off from the rest of the plumbing and run a seperate supply line from one of the pumps up to it? Then how would you work in the hot water supply? Hmmm I guess I'll have to wait till the boats unrapped first of all. :smt017
 
hey Skuza, where have you been since SRO? Good to see you found it over this way to CSR...From another L.St.Clair boater!
 
I think you will find that the water system is a continuous loop for the most part. My pumps are together but the supply and discharge lines are different.
 
Petep said:
hey Skuza, where have you been since SRO? Good to see you found it over this way to CSR...From another L.St.Clair boater!
I was having problems registering to the site. Good to see so many people from the old site here including Fwebster. My father would love to trade boats with you Petep if your interested! He almost bought a 2000 with 80 hrs on it a few years ago but the seller turned out to be a jerk. He still would love to own an '01 or newer with a hardtop but unfortunately business has been slow the past couple years so that idea is on the back burner. So hey if you need any work done on your cars come to Fleetwood Collision! We're right in your neighborhood on 8 1/2 and Harper.
 
Have you considered adding an accumulator tank? It doesn't necessarily give you more pressure, but it does a nice job of 'evening out' the flow to minimize the surging.
 
Don't overlook the airator in the faucet. It can change your sense of water pressure. Without it, it's like a garden hose without a nozzle - just sort of runs out. Add the nozzle and you can squirt it across the yard. Since all water supplies are low volume on a boat you need a working airator.
 
My neighbors' 97 400DA has one noisy water pumpt. Not sure if that is normal or not. If it is and he had TWO of those going it would wake up the marina.
 
Our water pump isn't that bad. I found some of the lines that were vibrating against the hull or structure and insulated them and its reasonably quiet. Now if you get some air in the lines it gets noisey.
 
I'm not sure of the pumps Sea Ray uses, as I have yet to get mine, but on my old boat it had a strainer on the outlet of the pump that would cause pressure loss when it got stuff in it.
I don't think adding a second pump would do much for you unless you are trying to use multiple faucets at the same time. Even if you decide to run a second pump you would have to create two different "zones." Like one pump on the cold side and a pump on the hot side.

If it was me, and it REALLY bothered us, I would replace the pump I have with a higher volume pump.
 
The 400DA uses a single Shurflo #2088-733-244 pump that produces 3.3 GPM of flow. When you open an faucet that flows 4-5 GPM you run out of water and are limited to the pump's putput pressure. That makes it seem like you run out of pressure at the faucet.

The next and only larger pump that fits in the same space with the same plumbing and electrical connections is a Shurflo # 2088-712-244 which increases flow to 3.8 GPH which is only a 15% improvement. The better alternative is the first one I suggested in the second post in this thread.....if you are going to spend $250 for a pump, add an additional parallel pump to increase the volume output. A second 3.3 GPH pump at 45psi will essentially double your capacity and give you water flow like you have at home.
 
"A second 3.3 GPH pump at 45psi will essentially double your capacity and give you water flow like you have at home"

Then all you need is a reservoir like you have at home!

... Oh, and don't forget to upgrade the pumps in your shower sump!
 
The two pump set up is definately the way to go. I assume the 480 DB is similar to the 450/460 DA set up and the dual pumps also give redundancy. I've had to replace both pumps due to failure and thank goodness they didn't fail at the same time. No water on the boat would be miserable.... that would be worse than no sat TV.
 
That is a good point about the shower sumps that I did not think of! If your pumping that much more water into the sumps they better be able to keep up. I'm assuming that since they cycle on and off during a shower and every 20-30 seconds at that, they should be able to keep up with a little more water? Good point that I'll have to make sure of if I do upgrade. :thumbsup:
 
THe 400 has an accumulator on it so no resevoir is needed.

You double the capacity so you don't run a single pump out of water by opening a faucet that flows more than 3.3 gpm, but you will never use the full capacity of both pumps.

Why is the shower sump a concern? It has a Rule 2000 gph pump in it. That's about 10X the flow of the water pumps and besides, not all t he drains in a 400 go into the shower sump....some go directly overboard.
 

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