Tunning down pump

[mojo]

Rbredding;613396 wrote: ball valves are not bad, but a gate valve would be better, IMO...

it's easier to fine tune a gate valve..

I agree, but I've tried this several times on my sequence pumps, and the gate valves always end up leaking on me. Either I'm not buying the right brand of gate valves, or their seals aren't as tight.

I've never had a ball valve leak.

 

[rbredding]

mojo;613553 wrote: I agree, but I've tried this several times on my sequence pumps, and the gate valves always end up leaking on me. Either I'm not buying the right brand of gate valves, or their seals aren't as tight.

I've never had a ball valve leak.

probably because they're almost always "all on" or "all off"



interesting, though...

The ones that I have, King I think, can be rebuilt without removal. Water must be drained off them, of course..

 

[rbredding]

graph it... !


:woohoo:

 

[grouper therapy]

Acroholic;613468 wrote: I saw zero drop on a kill a watt when I closed it, and I tested from open to closed and all stages in-between. Either way, I'd consider an 8 watt drop negligible, especially on a pump like a PW 200 that draws 290 watts. If anyone has to close a pump output 2/3 to get the flow they need, they definitely need a smaller pump. I don't know which of our meters was correct, but I saw no drop with PW/Iwaki type pumps. The meter I used was borrowed from Sailfish.

The drive mechanism of PW pumps is different that Mag Drive/Eheim types and Reeflo types. PW pumps spin at the same rate regardless of whether you throttle them down or not because it is a magnet attached to a motor, that makes another independent magnet/impeller assembly spin. Reeflos do not because the drive shaft is directly connected to the impeller, and Eheim/mag drive types use a non moving electric coil that drives a round magnet attached to the impeller. (I know you know all this Dave, just FYI to others reading that may not).

Not sure of the actual physics behind it, but I would guess if there is a tiny drop in wattage draw on a PW/Iwaki type pump when mostly closed, it is because the impeller magnet is causing a bit of drag on the constant speed magnet attached to the drive motor. The impeller magnet is spinning slower because the output is restricted, causing a bit more drag on the motor side magnet. Just a guess.

I can't say that my kilowatt is dead on but I checked these readings with a fairly nice multimeter and it was dead on with the kilowatt in ampere readings which I converted to watts.

 

[ichthyoid]

ichthyoid;613449 wrote: If you refer to the seals part Dave, on a magnetically coupled pump you are correct, as they are seal-less.

These do have shaft end bushings that will wear prematurely, though.

However the efficiency part is still valid.

Per my easrlier post.

grouper therapy;613514 wrote: Man guessing at flow restriction by the position of the ball valve handle is deceiving!!!
Ok here is what I ended up with I tested a Coralife 1100 p pressure pump
164 watts @ 15 GPM
147 watts @ 7.5 GPM 50 % reduction of flow and 9.64% wattage reduction
137 watts @ 5 GPM 75% reduction of flow and 16% wattage reduction

Interesting.

(FWIW- The third one above is a 66% reduction in flow, not 75%)

However, as to efficiency...

Here is a calculation of how much power is required per gallon of water flow (w/gpm) or efficiency, for this particular pump with the ball valve open and with the ball valve reducing the flow, as mentioned above.

Efficiency=
164 watts/15 gpm = 10.93 w/gpm (baseline efficiency)
147 watts/7,5 gpm= 19.6 w/gpm (45% reduction in efficiency)
137 watts/5 gpm = 27.4 w/gpm (60.1% reduction in efficiency)

 

[grouper therapy]

Acroholic;613468 wrote: I saw zero drop on a kill a watt when I closed it, and I tested from open to closed and all stages in-between. Either way, I'd consider an 8 watt drop negligible, especially on a pump like a PW 200 that draws 290 watts. If anyone has to close a pump output 2/3 to get the flow they need, they definitely need a smaller pump. I don't know which of our meters was correct, but I saw no drop with PW/Iwaki type pumps. The meter I used was borrowed from Sailfish.

The drive mechanism of PW pumps is different that Mag Drive/Eheim types and Reeflo types. PW pumps spin at the same rate regardless of whether you throttle them down or not because it is a magnet attached to a motor, that makes another independent magnet/impeller assembly spin. Reeflos do not because the drive shaft is directly connected to the impeller, and Eheim/mag drive types use a non moving electric coil that drives a round magnet attached to the impeller. (I know you know all this Dave, just FYI to others reading that may not).

Not sure of the actual physics behind it, but I would guess if there is a tiny drop in wattage draw on a PW/Iwaki type pump when mostly closed, it is because the impeller magnet is causing a bit of drag on the constant speed magnet attached to the drive motor. The impeller magnet is spinning slower because the output is restricted, causing a bit more drag on the motor side magnet. Just a guess.

I did not get a drop of wattage at all either on one of my test .Then I realized that I had not reset the meter to watts when I changed pumps. The Kill a watt meter defaults back to the line voltage reading that doesn't change. That may be what happened to you.

 

[budsreef]

The only gate valve or ball valve I have ever had leak were threaded types. I have never had a glued slip connection leak of any type.

mojo;613553 wrote: I agree, but I've tried this several times on my sequence pumps, and the gate valves always end up leaking on me. Either I'm not buying the right brand of gate valves, or their seals aren't as tight.

I've never had a ball valve leak.

 

[rbredding]

I've got a gatevalve right now that will leak if you "pull on the knob" (stop.it.)....



it's fully open right now and doesn't leak.

 

[grouper therapy]

Just for some nonbelievers, this was taken from Sequence website

ALL OF OUR PUMPS CAN BE “VALVED BACK” AS LONG AS ITS DONE ON THE DISCHARGE
LINE. IT WILL NOT ONLY REDUCE THE FLOW, IT WILL LOWER THE WATT USEAGE AND
EXTEND THE LIFE OF THE MOTOR AND THE SEAL!

 

[rbredding]

yeah... I've quoted that from the reeflo site dozens of times.. people still doubt it...


I guess... Hater's gonna Hate?