First try: really low flow outta my pump?!?

[Moe_K]

I fired up the return lines tonight for the first time.

I don't have any leaks in the plumbing, thank goodness.

But I am getting a trickle out of each of the return lines.

The pump is a brand new Dolphin Ampmaster 2100. I'm dealing with 10 feet of head. On the graph, the pump should be pushing 20 gal/min, which is 1200 gal/hr.
Divide that in half (because I have two return lines), and I should be seeing 600 gph from each lockline, right?

The main return line from the pump rises 8' to a T, than runs horizonally for 3 feet (to each side). There's another 90 degree turn there, as the lines go vertical again under the bulkheads. From there they go up a couple of feet to a last 90 degree turn to flow through the locklines and into the tank. So that's three 90 degree turns. Those turns still shouldn't cut my flow down to a trickle, right?

Any ideas on why so little flow?

I checked, and the two ball valves are in the open position.
Is there an adjustment on the pump to dial back the output?

 

[Tstone]

Moe I think every 90 is equal to one foot of head. So if you have three 90's on each side, that's six 90's total along with a T which probably equals another foot of head.

That makes me think you could theoretically be looking at about 17 or 18 ft of head total??

 

[Moe_K]

Ok, I see. The T was included as one of the 90's; so we're looking at 6 extra feet (3 per side).
Just checked the graph, jeez, with 15' of head the flow drops of to zero.

 

[nichols]

Moe I think every 90 is equal to one foot of head. So if you have three 90's on each side, that's six 90's total along with a T which probably equals another foot of head.

That makes me think you could theoretically be looking at about 17 or 18 ft of head total??

Moe I ran into the same problem plumbing my 210. I switched the T out to a Y and could then change the 90's to 45's. It made a huge difference. Your welcome to check out my system if it helps.

 

[Tstone]

You need a bigger pump.

 

[Moe_K]

Moe I ran into the same problem plumbing my 210. I switched the T out to a Y and could then change the 90's to 45's. It made a huge difference. Your welcome to check out my system if it helps.

Ugh. Good gawd, I don't want to replumb this thing.


Looks like I have to, though.
I'll lift the sump a foot; and use spaflex instead of rigid PVC after the split.

 

[wrassefan]

Moe, shut down one side of the return and see if the return flow improves. Disconnect the pump to see if no blockage coming from the bulkhead feed.

 

[nichols]

Ugh. Good gawd, I don't want to replumb this thing.


Looks like I have to, though.
I'll lift the sump a foot; and use spaflex instead of rigid PVC after the split.

Want to take a guess how many times I replumbed mine?

 

[Scuba_Dave]

I have a Dolphin pump that puts out 5000gph

That'll do it

 

[nunofs]

Also, the locline cuts down on the flow quite a bit (especially if you're going from a larger diameter PVC pipe to locline and/or are using the flat locline nozzles).

Nuno

 

[Moe_K]

Ugh. Messing around with the RC head loss calculator, I find I'm losing most flow when the return line drops to 3/4" diameter. No way to avoid that, as the hole in the bottom of the overflow only allows a 3/4" line.

 

[Moe_K]

Moe, shut down one side of the return and see if the return flow improves. Disconnect the pump to see if no blockage coming from the bulkhead feed.

Yeah, plugged the right side, and the left side improved a bunch (and vice versa).
Good idea.

 

[delta]

are there 90s at the top where the loc line is? so instead of three you have
five? if thats the case rc calc says
"Total losses are 11.32 feet of head pressure, or 4.89 PSI. with a flow rate of 245 GPH. Process took 26 iterations."

 

[Moe_K]

I counted that 90 turn (x2), Greg.

Total: six 90 degree turns on the return lines, including the T, the turn up, then the turn horizontal before the lockline.

 

[Chris L]

moe use the no kink black hose. i used it in my basement sump and i had to throttle my little giant three back to more then half. the only 90 degrees is going into the tank. so almost no head loss

 

[Chris L]

and tank back

 

[Moe_K]

Interesting note: I let the RO/DI drip for a few hours last night. The more water that went into the sump, the faster the flow in the return lines.
As Matt told us in his presentation on fluid dynamics, head loss is measured from the top of the water level in the tank to the top of the water in the sump. If I rasie the water level in the sump, I cut down on head pressure.
Sweet physics.

 

[Scuba_Dave]

I have the same "issue" with my skimmer. As water volume drops in the sump, the skimmer level drops, and it doesn't work as well
And if the return pump goes out, the water level rises too high, & the input fitting leaks

 

[RichConley]

Moe I think every 90 is equal to one foot of head. So if you have three 90's on each side, that's six 90's total along with a T which probably equals another foot of head.

That makes me think you could theoretically be looking at about 17 or 18 ft of head total??

Thats not true.

Every 90 degree is equal to 1 foot of horizontal run. Not one foot of head.