Pressurized water accumulation tank pressure?

[Hermit Scott]

My C30 came with a shurflo fresh water pump and what looks to be a 5 gal. accumulation tank or pressure tank. The boat sat for quite a while so I figure the pressure tank needs replacing. Tell me if this is right; the pressure tank evens out the flow from the faucet, and allows the pump to run less frequently than if there was no pressure tank? I lived in a house with a well and that is what I gathered from that experience.
I have a new 20 gal. pressure tank still in the box. The max presssure is 100 psi. My friend has two 5 gal. accumulation tanks for a water heater, but their max pressure is 40 psi. All the tanks in question are brand new. He is willing to trade the two 5 gals for my 20 gal.
(this sounds like a junior high math question)

Would it be better to install the 20 gal or just one of the 5 gal. and have one for a spare, or install both of the 5 gal.?

The pump has gal. per minute and amps but I didn't see what the pressure is set at? There should be two pressure settings, a kick on pressure(minimum pressure) and a shut off pressure(max pressure). What pressure are these things set to shut off at? I am not sure the exact model # of the pump. But I think it was 7 amp 2.8 gal per minute.

Since the pressure tanks are different max psi, which would be best for use on my boat?

 

[Don12364]

Hermit,
My Rule pump comes on at about 1.5 bar (20 psi) and switches off at 4 bar (60 psi). I fitted a 10 litre (2.5 US gal) accumulator after discovering that a 1litre (1/4 US gal) was not large enough.

The main problem is when people get up in the night for a pee and wash their hands; the pump comes on and wakes up everyone else. So you only need enough volume to cater for this and if your crew need more than 5 gals a night to wash their hands then it must have been a pretty good night!
Accumulators have an internal diaphragm across their innards which separates the water from the air and pump pressure forces this back as the pressure rises.

My accumulator is fitted with a Schraeder car type valve so to measure the pressures I used a car type pressure gauge. First just after the pump has switched off and again by opening a faucet and waiting till the pump comes on again and quickly switching it off. Then measure the pressure again to get the switch on pressure.
Now, open the faucet again with the pump off until water stops flowing and use a car footpump increase the pressure in the accumulator until it is just below the pump switch on pressure. This will ensure the diaphragm is fully towards the water inlet pipe and should give the maximum use of the stored air volume and pressure to maintain water flow.
Sorry if it sounds a bit complicated but, in fact, it only takes a few minutes to set up and, once done, one never needs to adjust it again.
See Shurflow link:-
http://www.shurflo.com/pdf/Marine/product_data_sheets/Fresh Water Pumps/pds-3901-0206.pdf

 

[Ross]

Unless you have an unlimited water supply I think the pump should be manual start with a push and hold switch and automatic shutoff and a five gallon accumlator tank is plenty. This way carelessly leaving a faucet running will only waste five gallons and not pump all of you water overboard

 

[sailingdog]

I'd second what Ross said... beats having an empty fresh water tank any day... also, the pressure you need on a boat isn't that high. Most houses have a regulator that keeps domestic water pressure to 60 PSI. 100 PSI is too high and a 20 gallon accumulator tank is a waste of water and space on a boat 30' LOA.

 

[Maine Sail]

A 5gal...

A 5 gallon accumulator tank is HUGE !!!!! You don't need a diaphragm tank that big trust me. I've used the Jabsco 30573-0000 1 litre accumulator tank for years and it performs flawlessly. The pump does not cycle that often and it keeps a very even flow to the faucets. A 5 gal tank on a 30 footer takes up a lot of valuable space..

Another option is one of the newer VSD pumps which does not require an accumulator tank...


Jabsco 30573-0000 (LINK)

 

[sailingdog]

And he's thinking of using a 20-gallon tank...

A 5 gallon accumulator tank is HUGE !!!!! You don't need a diaphragm tank that big trust me. I've used the Jabsco 30573-0000 1 litre accumulator tank for years and it performs flawlessly. The pump does not cycle that often and it keeps a very even flow to the faucets. A 5 gal tank on a 30 footer takes up a lot of valuable space..

Another option is one of the newer VSD pumps which does not require an accumulator tank...


Jabsco 30573-0000 (LINK)

 

[Tim R.]

I installed a Jabsco VSD pump and it is so much quieter than a conventional pump. The only time it is loud is when showering and even then it is quieter than a normal pump. It does have it's good and bad points. With my battery monitor, I noticed the pump was always drawing amps. I thought maybe it had something to do with this new design. Because of this we always shut off the pump when we did not need pressure water. One night my admiral accidentally left the pump on and in the middle of the night I heard the pump get noisy. It had drained the tank into the bilge and got noisy when it started sucking air. Once I fixed the leak, the pump dropped back to zero amps. We still tend to switch off the pump at times but not as much.

BTW, Jabsco support was lousy when the pump developed a problem. They were very hard to get a hold of and rarely returned calls. At one point I was asked for my name, address and phone and was assured I would get a call. A week later a new pump showed up on the doorstep. They were not interested in getting the old pump back for troubleshooting.

 

[Ross]

I have a whale foot pump for my sink water and it works very well. I use a 5 gallon stainless steel garden sprayer tank with a hand pump on it for pressure cold water. Water is heated on the stove and stored in 1 gallon coffee dispenser thermos's at the galley sink and at the sink in the head.
1 PSI will lift water 2 feet. I get a good flow at anything over about 5 psi with my pressure tank under the galley sink. If I have a complete electrical failure I can still get water at both sinks.

 

[sailingdog]

While they might be hard to get a hold of, they did fix your problem pretty well...so I think they're a bit above a lot of the other companies that are both hard to get a hold of and never fix the problem the customer is having.

BTW, Jabsco support was lousy when the pump developed a problem. They were very hard to get a hold of and rarely returned calls. At one point I was asked for my name, address and phone and was assured I would get a call. A week later a new pump showed up on the doorstep. They were not interested in getting the old pump back for troubleshooting.

 

[Tim R.]

While they might be hard to get a hold of, they did fix your problem pretty well...so I think they're a bit above a lot of the other companies that are both hard to get a hold of and never fix the problem the customer is having.

Fair enough Dog. I was happy to receive the new pump although this process took more than 3 weeks and the lack of communication is what really irks me.

 

[Stu Jackson]

There's always Shurflo.

 

[Hermit Scott]

My thought was, I would install the 20 gal pressure under the cockpit and have extra water storage. Would that give me 20 extra gallons? or 10?

If I trade for the 5 gal., the max pressure is 40 psi. Do I need to get a new pump that will kick on at 28 and kick off at 38? OR will the one I have adjust?

Donalex says his pressure range is 20psi to 60 psi. The 5 gal tanks are max 40 psi. Do I need/want that much water pressure?

 

[Ross]

Hermit, Why the concern about pressure? Fill a large cooler with water and open the drain and observe the flow rate. You want to be able to control the water usage on your boat so as to not waste any. A dish pan half full of hot water and detergent will do a do a fine job of washing up after a meal and just a little rinse water will finish the job. If you use more than about three quarts of water for that you will soon run out.

 

[Hermit Scott]

pressure

I already have pumps and storage tanks and pressure tanks. It would actually be more expensive to convert to manual pumps or even hang water from the ceiling in bags.

So I am pretty committed to using what I have right now instead of spending more money. My concern about pressure is that the pressure tanks match the pump, not that I have 135 psi to remove varnish.

 

[Ross]

You can adjust those pressure switches for turn on and turn off. It will require more power to pump a gallon of water at 30 psi than it will at 15 psi.

 

[Tim R.]

My thought was, I would install the 20 gal pressure under the cockpit and have extra water storage. Would that give me 20 extra gallons? or 10?

I do not think you will gain any extra capacity. When you tank empties, the pressure will flush all of the water out of the accumulator. When you fill you tanks, you will be limited by the size of the tank. The accumulator will only fill once you presurize and bleed the faucet. Maybe then you can top off the tank but once you learn how to use and conserve water this will not really make a difference.

The key to always having water is to monitor how much you use. Also key is having multiple tanks to act as a reserve when 1 tank runs out. I have 3 tanks(85 gal) on my boat but only ever use 2(50 gal). We don't usually drink our tank water(we could) but we do shower when anchoring. On a 2 week cruise, I think we refill twice.

 

[Maine Sail]

My thought was, I would install the 20 gal pressure under the cockpit and have extra water storage. Would that give me 20 extra gallons? or 10?

If I trade for the 5 gal., the max pressure is 40 psi. Do I need to get a new pump that will kick on at 28 and kick off at 38? OR will the one I have adjust?

Donalex says his pressure range is 20psi to 60 psi. The 5 gal tanks are max 40 psi. Do I need/want that much water pressure?

A domestic water accumulator tank that is only 40 PSI does not sound right to me. Be sure you are not getting a hydronic heating systems "thermal expansion tank". They are not the same thing and expansion tanks are not designed for potable water. As for added capacity I can think of many ways other than a monster accumulator tank to do this. These tanks are also split by an air bladder so added capacity will be minimal at lower working pressures. There are many items I would store in the lazarette other than a massive accumulator tank that will be far more useful to you when out cruising. I know at this phase it seems as though you have room but once you begin to load up & go you'll wonder where it all went..

 

[Hermit Scott]

The 5 gal. tanks are thermal expansion tanks. They did say max pressure 40 psi, precharged at 38 psi. Are those made to hook up to a blow off valve?

You are right, if I am going to have a 40 gal tank, half of it shouldn't be filled with an air bladder. Also the round shape is not very efficient to install on a boat.
I bought this becasue I thought I would need to replace the one I have. It was on clearance for $18.88, from $147. My friend has a diaphram dirty water pump and a new sureflow pump like the one my boat has now. I'll try to trade him for one of those. He wanted the tank I have for a reverse osmosis system. I guess those thermal expansion tanks aren't high enough pressure, he needs a pressure accumulation tank.
Allright, yet another time my ideas are thwarted by the practical and experienced!

 

[Maine Sail]

Hermit..

Thermal expansion tanks for sealed water systems are generally raw steel on the inside and designed to be used on a sealed FHW system that has an air elimination device in place. They absorb the thermal expansion of the water in the boiler when it is heated. They are also used in chiller systems. Most domestic FHW heating systems run pressures below 30lbs. therefore a 40 pound expansion tank is common. If used in a raw water system the air in the water system will cause rust in the potable water system.

Expansion or accumulator tanks designed for "pumped" domestic water, like from a well, boat or RV, or for thermal expansion from a hot water heater, when placed between the back flow preventer and the inlet, are designed for higher working or "street" pressures. There is usually a plastic liner inside a tank made for potable water systems to prevent rust formation or the tank itself is stainless...

Some tanks are designed only for sealed hydronic system systems such as the Amtrol Extrol line. Amtrol's Therm-X-Trol line, while similar in look and concept, is designed for domestic potable water and has a plastic liner.