Return pump to big? Vectra L1

[jimmyzhou]

just for clarity
drain is 1 inch
return is 1/2 inch

pump is 1 inch

On mine is pump 1 1/2 return 1 1/2to 1 inch and drain is 1 inch also

 

[Sleepydoc]

It is a fact , I work in heavy industry (petroleum chemical) and it's a standard, all pumps are fitted with a discharge check-valve. If u think about it, when you reduce the power on the pump it will not be able to push the main discharge column of water forward such as during feed mode , it will still be running but at a slower speed to continue feeding the manifold , chiller etc. without a check valve the water column has no where to go but backwards whilst the pump is still pushing water forward, these two opposing forces can severely damage the PLASTIC rotating components of the pump.

That still doesn't make sense. Think about the 'stress' put on the volute when the pump is running full speed. It's going to have the head pressure from the vertical rise (say 5 feet for an average setup) plus the pressure needed for the water to flow against the pipe resistance. This is dependent on the plumbing and flow, but another 6 feet of head pressure is not unreasonable. This means that at baseline flow, the volute is pushing against 11 feet of head pressure.

Now say we slow down the pump (assuming it's adjustable) to the point where the flow is exactly zero. at this point the pump is seeing 5 feet of head pressure, perhaps a bit less if you're running a manifold . If we slow down the pump even further to its lowest setting then we have a column of water flowing against the slowly turning pump. Even at this point, it's impossible for the stresses to exceed those at baseline flow. If we turn the pump off completely and let water siphon down, then the impeller will turn backwards, but even if it were fixed, then you have 5 feet of head pressure against the volute & impeller.

Most DC pumps are soft start pumps, but AC pumps ramp up to full speed virtually instantaneously. The stresses generated during start up far exceed the relatively gentle pressure caused by water back-siphoning.

Like mfinn said, conditions may be different for industrial sized systems, but if this was an actual concern for our systems the manufacturers would have made it clear by now.

OP:
Yes, if you do put a check valve in it has to be above any branching for a manifold. I would recommend putting a ball valve in as they can be handy for maintenance.

Something else you may want to do after you have everything set up and plumbed is turn the pump up to full speed to make sure it won't cause major issues if it accidentally gets turned on full power. The half inch bulkhead may actually serve as a safety limiter since the head pressure through it will increase rapidly with increasing flow.

 

[Dumaurier7]

Yeah, I worked in oil refinery's and other mills for 40+ years, and maybe you are right about the industrial sized pumps and pipes ( 2" up to 20" or even bigger) , but I highly doubt the same principles apply in aquarium pumps.
If this did apply, the pump makers would be all over it with warnings where warranty claims were made.

The same principles do apply, I've seen pumps with broken impellers which did not suck in anything and I've also seen impellers come loose for no reason at all. The warranty issue is a complicated one as there are way too many configurations possible when installing a pump, I decided to protect my $1100 investment by installing a $30 check valve, we are all free to do as we like!

 

[mfinn]

The same principles do apply, I've seen pumps with broken impellers which did not suck in anything and I've also seen impellers come loose for no reason at all. The warranty issue is a complicated one as there are way too many configurations possible when installing a pump, I decided to protect my $1100 investment by installing a $30 check valve, we are all free to do as we

I too own Red Dragon pumps and have been in contact with a company rep at Royal ExclusivUSA and he didn't mention anything to me. And being involved with this and a few other forums, this is a first for me.

Do you have any supporting links to discussions on the matter?

 

[mfinn]

[QUOTE="Dumaurier7, post: 3841607, member: 61797", I decided to protect my $1100 investment by installing a $30 check valve, we are all free to do as we [/QUOTE]

I agree there is many different ways to skin a cat and but I am standing firm on my statement when I said to skip the check valve when it is used for flood control.
Putting the return is a position so it doesn't overflow the sump ( power outage) is the best way to plumb a return.

 

[slief]

It is a fact , I work in heavy industry (petroleum chemical) and it's a standard, all pumps are fitted with a discharge check-valve. If u think about it, when you reduce the power on the pump it will not be able to push the main discharge column of water forward such as during feed mode , it will still be running but at a slower speed to continue feeding the manifold , chiller etc. without a check valve the water column has no where to go but backwards whilst the pump is still pushing water forward, these two opposing forces can severely damage the PLASTIC rotating components of the pump.

It may be fact in the petroleum industry but check valves are not needed and should be avoided in the aquarium industry. They are a liability and create unneeded head and friction loss and do nothing to reduce head pressure. As somebody who has been in the hobby for 30 years and works for a very well regarded pump and skimmer manufacturer, the idea that a check valve should be used because head pressure will create unwanted or unneeded back flow is a flawed logic for this hobby. Aquarium pumps are designed to overcome head pressure without worry about backflow. Any back flow if the power goes out will not harm the pumps.

Check valves rob pumps of flow and and with a DC or variable speed pump, they force you to run the pump at higher speeds to overcome pressure. The higher speeds can create additional stress on the pump as well as it's power supply because it's working harder, consuming more wattage and generating more heat. All of which can cause longevity issues with some pumps. While an AC pump may not generate more heat and may even consume less power with additional head, the head pressure or back flow (which is non existent when the pump is powered on) is not an issue at all. I suppose if you have an exceedingly high head, there may be some merit to this logic but most of us aren't running 20' of head pressure and those that are would be using suitable pumps such as pressure rated AC pumps or pressure rated DC pumps that are designed to deal with those kinds of head pressure.

There is NO reason to run a check valve on a return pump if the system and plumbing are properly designed and they should be avoid at all costs in our hobby.

 

[slief]

It is a fact , I work in heavy industry (petroleum chemical) and it's a standard, all pumps are fitted with a discharge check-valve. If u think about it, when you reduce the power on the pump it will not be able to push the main discharge column of water forward such as during feed mode , it will still be running but at a slower speed to continue feeding the manifold , chiller etc. without a check valve the water column has no where to go but backwards whilst the pump is still pushing water forward, these two opposing forces can severely damage the PLASTIC rotating components of the pump.

The ONLY plastic rotating components in a quality pump is the impeller. The shafts on quality pumps are either stainless, titanium or other quality material. If the impellers are getting damaged because of backflow when you switch to feed mode, I would suggest you find a different pump. Head pressure will NOT damage a quality pump regardless of the speed you run it at. Even if you use feed mode which in my opinion is silly since the flow from the return helps distribute food throughout the tank to fish and corals. It also impacts the skimmer since that typically needs to be shut off so it doesn't overflow. Return pumps should be set it and forget it. Shutting off or turning down power heads for feeding is a different story in some systems.

 

[Dumaurier7]

The ONLY plastic rotating components in a quality pump is the impeller. The shafts on quality pumps are either stainless, titanium or other quality material. If the impellers are getting damaged because of backflow when you switch to feed mode, I would suggest you find a different pump. Head pressure will NOT damage a quality pump regardless of the speed you run it at. Even if you use feed mode which in my opinion is silly since the flow from the return helps distribute food throughout the tank to fish and corals. It also impacts the skimmer since that typically needs to be shut off so it doesn't overflow. Return pumps should be set it and forget it. Shutting off or turning down power heads for feeding is a different story in some systems.

The plumbing in my system is 1.25" so I went with an oversized 1.5" check valve to ensure the valve does not actually restrict the flow, the flapper is " spring less" and is very light which makes it easily opened by the pumps pressure. When in feed mode the back flowing water pressure slams the valve closed making a noticeable sound, I do not want this pressure getting back to my pump. As for slowing or stopping the pump when feeding, I think this is a no brainer when your tank has an overflow as the food will go down the overflow before the fish can get to it, distribution throughout the tank is handled by the circulators (4 Gyres in my case) which are also slowed , but as I said before, to each their own !

 

[slief]

The plumbing in my system is 1.25" so I went with an oversized 1.5" check valve to ensure the valve does not actually restrict the flow, the flapper is " spring less" and is very light which makes it easily opened by the pumps pressure. When in feed mode the back flowing water pressure slams the valve closed making a noticeable sound, I do not want this pressure getting back to my pump. As for slowing or stopping the pump when feeding, I think this is a no brainer when your tank has an overflow as the food will go down the overflow before the fish can get to it, distribution throughout the tank is handled by the circulators (4 Gyres in my case) which are also slowed , but as I said before, to each their own !

Good choice on oversizing the plumbing. That always helps in reducing friction loss and I do the same thing when ever plumbing a system. That said, the check valve still creates additional head pressure even if it's oversized and it creates more than a valve or a T. Also, flapper valves are about the worse check valves you can use because they tend to seperate overtime which can create a catostrophic problem. The only kind of check valve I would ever condone are the rebuildable ones with the balls.

I see you run an RD3.. As the director of support for Royal Exclusiv, I can assure you the check the valve isn't needed. I've never ever seen an rotor come off the shaft in this scenario. They only time I have ever seen that happen is when somebody mishandles the impeller and pulls the rotor off the shaft when trying to remove the impeller from the pump. Aside from that, you have a very good warranty. The only plastic rotating part in these pumps is the rotor and it will not come off under the circumstances you mention and if it did, you are coverered under the 2 year warranty.

As for using feed mode, I too have an overflow and while some food may go over the overflow it's always a small amount and the vast majority gets distributed throughout the water column. In my case, I have SeaSwirls and I do wait until they are pointed aware from my overflow. Obviously every system and display is different but if you have to shut your skimmer down to accommodate feed mode, you are impacting the skimmer efficiency to a minor degree too. Having setup countless systems over the years and having had my current display for over 20 years, I don't really advocate the feed mode idea. Yea, you may save a bit of food but you do create additional wear and tear on your pumps by starting and stopping them or at least slowing them way down and stopping your skimmer pump every day. The risks of a pump failing because of that is far greater than the siphon issue you are concerned with. This comes from decades of experience both in the aquarium industry and well as the IT industry where may of the same power supplies are used to power electronic devices. More often than not, failures with electronics occur when you power something up as opposed to during typical power on hours. This goes for pumps, lights, computers, hard drives, light bulbs, etc. Any how, just my 2 cents.

Your setup looks very nice by the way. Just want to help avoid potential issues and dispel some concerns regarding aquarium related equipment and save people issues down the line. Avoid check valves where ever possible.

 

[Tray333]

It may be fact in the petroleum industry but check valves are not needed and should be avoided in the aquarium industry. They are a liability and create unneeded head and friction loss and do nothing to reduce head pressure. As somebody who has been in the hobby for 30 years and works for a very well regarded pump and skimmer manufacturer, the idea that a check valve should be used because head pressure will create unwanted or unneeded back flow is a flawed logic for this hobby. Aquarium pumps are designed to overcome head pressure without worry about backflow. Any back flow if the power goes out will not harm the pumps.

Check valves rob pumps of flow and and with a DC or variable speed pump, they force you to run the pump at higher speeds to overcome pressure. The higher speeds can create additional stress on the pump as well as it's power supply because it's working harder, consuming more wattage and generating more heat. All of which can cause longevity issues with some pumps. While an AC pump may not generate more heat and may even consume less power with additional head, the head pressure or back flow (which is non existent when the pump is powered on) is not an issue at all. I suppose if you have an exceedingly high head, there may be some merit to this logic but most of us aren't running 20' of head pressure and those that are would be using suitable pumps such as pressure rated AC pumps or pressure rated DC pumps that are designed to deal with those kinds of head pressure.

There is NO reason to run a check valve on a return pump if the system and plumbing are properly designed and they should be avoid at all costs in our hobby.

1+, In addition ,the petroleum industry use of check valves on their discharge side of centrifugal and positive displacement pumps reason is not to stop damage to the pump, but to stop the backflow of nasty chemicals from spilling everywhere when they are using when the pump is not pumping. Hydro static testing equipment also use check valves down stream just to hold pressure in the lines between needle valves, but I have yet to see a aquarium pump rated 7 g.p.m. at 2800 bar (40610 p.s.i.).

 

[George Lopez]

Dry fitting the plumbing. I decided to use the 3/4 inch pipe and reduce to 1/2 right under the tank just before the bulk head.

I was trying to fit a check valve in. I am running out of vertical space though. I was contemplating branching from the vertical bar to a horizontal manifold (last picture), but I think it might defeat the purpose of trying to use the check valve in the first place (if I have a branch before the check valve, I am thinking that it will just siphon out through the manifold.).

Please let me know if the current setup looks good or if there are any foreseeable problems with this plumbing.

Thanks!!

Ok imo id loose the ball check. I don't have any experiences with them in tanks but i do in the industrial field as a water plant mechanic and we have had issues with them locking in the open position or getting anything inside them and clogging (zip ties and small pieces of electrical were most of its culprits for not closing) so I'm thinking a small piece of algea will clog out open. The good part is they are easy to take apart but you won't know its clogged until you need it to work. If you want a checkid go with a clear y style or just adjust your water level to compensate for a power outage.

 

[butrflynlambie]

Thank you.. I have plumbed it without the check valve..