Royal Exclusiv Red Dragon 3 - High Pressure vs Flow?

[Mike.P]

I'm trying to figure out the difference between the two versions of the RD3 Speedy pump... Does anyone here have experience with them? I presume that the high pressure is meant to be used as a return, and the flow is meant to be used as a closed loop circulation pump; but both product pages say it can be converted to be used for circulation.

Any thoughts?

 

[Breadman03]

The pressure is tailored more toward people with basement sumps. What is your intended use?

 

[KStatefan]

Without pump curves I do not know how you can compare/determine any pump.

 

[Breadman03]

You can find them on the data sheets here.

http://royalexclusiv.net/en/flow-de...peedy-flow-230-watt-24-0m-10v-connection.html (flow)

http://royalexclusiv.net/en/flow-de...y-pressure-230-watt-19-0m-10v-connection.html (pressure)

 

[Mike.P]

The pressure is tailored more toward people with basement sumps. What is your intended use?

I'm looking to run it as a return pump for a Reefer XXL 625. It would also be split to a manifold, and possibly to a behind-the-wall refugium.

 

[KStatefan]

I do not know why retailers do not include that on the info page. To me that is just as important as price.

 

[Breadman03]

If the sump is under your stand, either will provide plenty. I had the flow for my 150 with basement sump and it could flow way more water than I needed.

 

[ca1ore]

The difference is almost certainly in impeller/volute design. Generally pumps designed for pressure will move less water at 100%, but lose less flow as back pressure increases. So it’s not return versus closed loop necessarily - though most closed loop application would be better served by a flow pump since back pressure is generally minimal. For a return pump you’d have to see which maintains higher flow at the back pressure in your system. Probably with a system that uses an in-stand sump with only modest back pressure the flow version would still be favored, but you’d have to check the published flow curves. Usually the pressure pumps only provide an advantage when head exceeds 10 feet, like in a basement return system (like mine).

 

[Mike.P]

The difference is almost certainly in impeller/volute design. Generally pumps designed for pressure will move less water at 100%, but lose less flow as back pressure increases. So it’s not return versus closed loop necessarily - though most closed loop application would be better served by a flow pump since back pressure is generally minimal. For a return pump you’d have to see which maintains higher flow at the back pressure in your system. Probably with a system that uses an in-stand sump with only modest back pressure the flow version would still be favored, but you’d have to check the published flow curves. Usually the pressure pumps only provide an advantage when head exceeds 10 feet, like in a basement return system (like mine).

Maybe both of these pumps are going to be overkill then, as my sump is in the stand, under the tank. These just caught my eye because of the build quality... Titanium components, bypass, etc., and German made doesn't hurt either. Thank you all for the feedback!

 

[Water Dog]

Let’s see if @slief will chime in. He’s a Royal Exclusiv USA rep.

 

[KStatefan]

Maybe both of these pumps are going to be overkill then, as my sump is in the stand, under the tank. These just caught my eye because of the build quality... Titanium components, bypass, etc., and German made doesn't hurt either. Thank you all for the feedback!

They have a 50 and 80 watt model also

 

[ca1ore]

Ultimately each of us must decide whether spending $700 plus on a return pump constitutes value. It does not for me, but might for you. I’m sure the build quality IS excellent .... frankly, it’d better be LOL.

 

[Breadman03]

I'll vouch for the noise of them, or rather the lack thereof. That is the main difference between my Blueline 70 and the RD3-230 (flow). If noise is your concern, then the price may be worth it.

 

[rkpetersen]

Those look like really nice pumps; I bet they are. Red Dragons are pretty well known for quality.
Next time I have a return pump fail, I may give one of these a try.

 

[slief]

The 100w pressure version is designed more towards systems with smaller returns. It has a 1” output where as the 100 watt flow version has 1.25” output. The pressure version consquently suffer less from friction loss with smaller plumbing than the flow version which doesn’t deal with head losses quite as well. In a system where the output or intake size isn’t restricted, the Flow version will hold its own against the pressure version so it really boils down to total head loss and or plumbing size restrictions. If you have restrictions with the return size, then the pressure version will likely be more efficient in terms of flow per watt than the flow version and in an unrestricted situation where you can deal with larger return sizes, then the flow version will be the more efficient pump watt for watt. At least unless you have much high head height or lots of elbows creating friction loss.

 

[Brian-222]

The 100w pressure version is designed more towards systems with smaller returns. It has a 1” output where as the 100 watt flow version has 1.25” output. The pressure version consquently suffer less from friction loss with smaller plumbing than the flow version which doesn’t deal with head losses quite as well. In a system where the output or intake size isn’t restricted, the Flow version will hold its own against the pressure version so it really boils down to total head loss and or plumbing size restrictions. If you have restrictions with the return size, then the pressure version will likely be more efficient in terms of flow per watt than the flow version and in an unrestricted situation where you can deal with larger return sizes, then the flow version will be the more efficient pump watt for watt. At least unless you have much high head height or lots of elbows creating friction loss.

What would be a good start point to set the red dragon 3-100w flow pump at for a 150 gallon tank with a 39 gallon sump. I can't find a head pressure or flow chart anywhere for that pump. Any help would be appreciated.