FW pump variable speed or constant speed with expansion tank.

[Ka_sea_ta]

It seems that losing pressurized fw would be a show stopper on a cruise. So to get the most reliable fw system, is it a variable speed pump or a constant speed pump that typically needs an expansion tank to deliver a consistent volume of water? either way I think a spare pump is probably a good idea.

 

[HopCar]

When the variable speed pumps first came out they had a lot of problems.
Jabsco stuck with the variable speed idea while ShurFlo gave it up. Shurflo came out with a constant speed pump with a built in bypass that fed excess water back to the inlet side of the pump.

I think the old fashioned pressure switch pump with expansion tank is more reliable but it’s been some time since I was selling these pumps.

Yes carry a spare pump.

 

[DavidM]

Variable speed pumps have gotten much better over the years and are now much quieter. The pressure switch on constant speed pumps is a common failure item.

I would stick with what you have unless it is an older variable speed. Then replace it with a new one and keep the old one for a spare.

David

 

[tiltrider1]

Variable pumps last longer and run smoother if you use them with an accumulator. Even the manufacturers say this deep in there literature.

 

[Comodave]

In a previous boat I put in a variable speed pump. It was a long time ago but it didn’t last long. The variable pump made really strange noises and didn’t perform well. I took it out and put in a traditional pump with a 1 gallon accumulator tank. Worked great.

 

[tiltrider1]

It seems that losing pressurized fw would be a show stopper on a cruise. So to get the most reliable fw system.

If you really want a reliable system don’t buy an inexpensive membrane pump. Buy a Marco screw pump. They are 3x more expensive.

Membrane pumps are cheap and work well but they do not have the best longevity.

Another trick is to use the same pump for wash down as well as FW. This way you always have a back plan.

 

[rslifkin]

I agree with carrying a spare. Any good quality pump should work fine, although I prefer a constant speed pump, either with or without bypass. Personally, I'm using a constant speed pump with a 5 gallon accumulator tank. It gives a bit over a gallon of water between pump cycles, so the system is pretty smooth and quiet to use.

For durability issues with the cheap pressure switches on a lot of pumps, you can fix it with a relay. Let the pressure switch trigger a relay instead of directly handling the pump motor current and the switches tend to last a lot longer.

 

[O C Diver]

I wanted more pressure so went with a Jabsco 6 GPM, 60 PSI pump. Wanted a more reliable and adjustable pressure switch, so installed a Square D well pump switch. I also didn't like the short cycling and think it shortens the life of the pump, so installed a residential accumulator tank which gives me around 3 gallons between pump cycles.

Ted

 

[rslifkin]

I wanted more pressure so went with a Jabsco 6 GPM, 60 PSI pump. Wanted a more reliable and adjustable pressure switch, so installed a Square D well pump switch. I also didn't like the short cycling and think it shortens the life of the pump, so installed a residential accumulator tank which gives me around 3 gallons between pump cycles.

Ted

That sounds pretty close to what I did, although with a slightly smaller accumulator (just found my notes, it's 5.5 gal, measured at 1.2 gal between cycles). And I used the 4 GPM / 60 PSI version of that Jabsco pump (I used the one meant as a washdown pump, as it doesn't have the internal bypass like the fresh water pump version).

I burned up the pressure switch after a few months and it started sticking, so I put the replacement on a relay. I would have gone for an external pressure switch, but I couldn't find an ignition protected one, and plumbing wise, keeping it out of the engine room would have been a pain. So I used a sealed relay and the stock pressure switch instead. It's been working fine other than occasionally chattering a couple of times right as it reaches shut off pressure (which is what burned up the first pressure switch). The relay contacts seem to tolerate it fine though, and at some point I may get tired of it and swap to an external pressure switch, or build in a slight delay for the relay circuit or something.

 

[O C Diver]

That sounds pretty close to what I did, although with a slightly smaller accumulator (just found my notes, it's 5.5 gal, measured at 1.2 gal between cycles). And I used the 4 GPM / 60 PSI version of that Jabsco pump (I used the one meant as a washdown pump, as it doesn't have the internal bypass like the fresh water pump version).

I burned up the pressure switch after a few months and it started sticking, so I put the replacement on a relay. I would have gone for an external pressure switch, but I couldn't find an ignition protected one, and plumbing wise, keeping it out of the engine room would have been a pain. So I used a sealed relay and the stock pressure switch instead. It's been working fine other than occasionally chattering a couple of times right as it reaches shut off pressure (which is what burned up the first pressure switch). The relay contacts seem to tolerate it fine though, and at some point I may get tired of it and swap to an external pressure switch, or build in a slight delay for the relay circuit or something.

My tank is 8.5 gallons. If you adjust the air pressure side of the accumulator tank to a couple of PSI over the pump cut in pressure (with no water pressure on the other side), you will maximize the volume between pump cycles.



Mine lives very happily in the lazarette.



Ted

 

[rslifkin]

My tank is 8.5 gallons. If you adjust the air pressure side of the accumulator tank to a couple of PSI over the pump cut in pressure (with no water pressure on the other side), you will maximize the volume between pump cycles.

Mine lives very happily in the lazarette.


Ted

I had to sacrifice a little volume by keeping the pressure lower, as my tank is in the engine room. Pressure variation from cold boat in the spring to hot engine room after running all day in August is noticeable, so I had to lower the pressure to avoid it getting above the cut-in pressure in the second case.

 

[Don L]

I have the constant pressure pump with expansion tank, but have been on a sister boat with the variable speed pump.

I like the expansion tank system better as with the variable speed pump the pump comes on with every little water use and seems to cycle a lot if you are using water slowly as the pump doesn't seem to like to run that slow.

 

[AlanT]

Like others I have experienced many many failures of variable speed membrane FW pumps of different manufacture in the past. Ever since my Hylas (delivered 2006) came with two identical variable speed membrane pumps plumbed in parallel with valves to switch from one to another I have felt this was the best solution. My next boat (Bayliner 4788) had plenty of space to plumb a second membrane pump in parallel which I did. I went through 3 pumps in 6 years! My current boat has a much more robust single speed belt driven pump with an accumulator tank, but no suitable space to plumb in a spare so I carry an identical pump which I can switch out easily if needed.
~A

 

[twistedtree]

I think if you can find the space, a constant pump with accumulator tank is the preferred set up. But space is always at a premium, and sometimes there just isn't room for an accumulator.

 

[catalinajack]

If space is avaiable for installation, a Grundfos 120VAC pump shines in comparison to most any 12VDC pump. It delivers constant 60 psi pressure and volume to spare.

 

[socalrider]

We use a constant speed pump with the bypass valve. No accumulator. We ran through a pressure switch every season (~6-7 weeks constant use by 5+ people) - terrible reliability.

This season following some recommendations on this forum I wired in a relay so that the ~10a (?) of current isn't flowing through the constantly operating pressure switch. Hoping that helps; I'm carrying a spare pump and a spare pressure switch just in case.

 

[Jc180]

Agree with previous posts that variable speed pumps have historically not been reliable, but have greatly improved. Had my share of failures, but have had a variable speed pump in service now without incident for over 5 years. I prefer the variable speed pump, it is a lot quieter and delivers a more constant pressure output. Find most noticeable in the shower, no variation in hot water. Admittedly, the same can be achieved with a larger accumulator.

 

[ssurabus]

I removed my accumulator pump years ago (6+) and have used a variable speed pump with no trouble. I like the simplicity of no accumulator tank. I know others have reported problems over the years, but based on my experience I would stick with variable speed (or the bypass type pump which I'm just hearing about) and skip the accumulator tank. I fully agree with carrying a spare.

 

[socalrider]

I removed my accumulator pump years ago (6+) and have used a variable speed pump with no trouble. I like the simplicity of no accumulator tank. I know others have reported problems over the years, but based on my experience I would stick with variable speed (or the bypass type pump which I'm just hearing about) and skip the accumulator tank. I fully agree with carrying a spare.

Curious what brand(s) are you and others having success with in variable speed drive?

FWIW the bypass-style pump I'm using is the Shurflo 4048153E75. Wouldn't recommend due to the annual switch failure, but hoping it'll be more reliable with the relay I installed. If it's not, I'll look into variable speed drives.

 

[DDW]

There are two kinds of variable speed: membrane and Marco (gear type). I've had several membrane (both Jabsco and Sureflo) variable speed pumps fail, now have two Marco pumps which have not failed. The Marco seems superior but does cost more. If you have a very small water system, it works better with a small (RV 1 pint type) accumulator. With a normal sized water system, that makes little difference.

One downside of the Marco is it is not really a positive displacement pump, and will not self prime well. Not a problem if the pump is below the water tank, but if installed above the water tank it can have problems.

 

[arthurn]

I have a Marco UPE6 variable speed pump on my 38 ft helmsman. I have had this pump for 3 years without a problem. The first Marco I had when I purchased the boat 4 yrs ago, the boat was 2 yrs old then failed 2nd to a stuck non-serviceable check valve. My problem was I left the pump on for relatively long periods of time when I wasn't on the boat. Now if I am not going to be on the boat for more than 3 days I turn off the fresh water pump and have not had a problem. I do agree with others though, I do carry a spare.

 

[Simi 60]

If you really want a reliable system don’t buy an inexpensive membrane pump. Buy a Marco screw pump. They are 3x more expensive.

What size Marco are you using?

 

[Simi 60]

We have been getting a good run with the 20 LPM 24v Vetus pumps at around $150.

3 year warranty did come into play on the smaller model, but Vetus upgraded us to the larger model when they replaced under warranty.

Accumulator tanks?
We have killed off two Jabsco ones and two larger household ones, bladders burst on all.
Now have a 1.25 litre soft drink bottle Macguyvered into the system, try bursting that.

Don't mind spending more on a better pump if it can be proven it is actually better.

.

 

[Simi 60]

I have a Marco UPE6 variable speed pump on my 38 ft helmsman. I have had this pump for 3 years without a problem. The first Marco I had when I purchased the boat 4 yrs ago, the boat was 2 yrs old then failed 2nd to a stuck non-serviceable check valve. My problem was I left the pump on for relatively long periods of time when I wasn't on the boat. Now if I am not going to be on the boat for more than 3 days I turn off the fresh water pump and have not had a problem. I do agree with others though, I do carry a spare.

Leaving it on how?
Surely they have a pressure switch that turns them off when taps are off.

 

[tiltrider1]

What size Marco are you using?

I use the UP12/E at 9.5 gallons per minute. This is more pump than is necessary. The UP6/E at 6.9 gallons per minute is the most commonly used model.

I have it connected to a 5 gallon accumulator.

There were three reasons why I ended up with the bigger unit.

1) matched my pipe size, no adapters needed.
2) Vendor wanted to reduce stock on the UP12 and made a sweet deal.
3) I thought a pump that doesn’t need to work hard would have a longer life.

 

[arthurn]

Leaving it on how?
Surely they have a pressure switch that turns them off when taps are off.

Your right, the pressure switch turns the pump off but it maintains the system pressurized. By turning the pump off on the panel, I then open a faucet to let the pressure off. This has kept the check valve from being stuck/sticky.

 

[Simi 60]

I use the UP12/E at 9.5 gallons per minute. This is more pump than is necessary. The UP6/E at 6.9 gallons per minute is the most commonly used model.

I have it connected to a 5 gallon accumulator.

There were three reasons why I ended up with the bigger unit.

1) matched my pipe size, no adapters needed.
2) Vendor wanted to reduce stock on the UP12 and made a sweet deal.
3) I thought a pump that doesn’t need to work hard would have a longer life.

Thanks
The UP12/E is a $1200 pump here
The UP6/E would do us, but still close enough to $1000

If I could be guaranteed it'd be the last pump install I ever did I'd probably have one

The pressure on the Marco could be a worry for us with our main bathroom on the top deck.

Marco is 36psi
Vetus is 61 psi

I know when we were running 240v pumps for a while, while the output was fine on the lower level it had noticeably dropped on the upper level forcing us back to the $150 Vetus

https://vetusonline.com/english/catalog/product/view/id/2106/s/wp2420/

 

[tiltrider1]

The Marco is 36psi at 1/2”. The Vetus is 61 psi at ?

 

[Simi 60]

The Marco is 36psi at 1/2”. The Vetus is 61 psi at ?

1/2 inch spigots on pump so I'm guessing 1/2 inch?

 

[tiltrider1]

I’m not enough of a plumbing expert to know if the Marco would do your job. Usually the GPM is the important number since most boats are not pumping vertical. Your needs are a little different. First you need to determine the vertical and then the pressure needed. Then we could check the GPM rate available at your required pressure.