Messages

1

Frequently Asked Questions / Suggestions for a cheap inline flowmeter (jet pump)

« on: March 30, 2015, 12:55:51 PM »

I'm noticing that I really would like to have a flow meter on the output of my RJC-100 jet pump, for a variety of reasons.
The timed-bucket method is too slow, and I often am not pumping into an open bucket.
It would help optimize the setting of that brass 'jet-control' screw adjustment.
It would be much easier than trying to infer the flow from the very incomplete pump performance table provided by Red Lion.

I'm just seeking a tapered tube, and the peak pressure of my pump is less than 100 psi.
I assume it would be harder to find one for those deep-well sumbersibles.

If you don't have a favorite, maybe you could suggest niches where i might search around.
I don't need high accuracy, don't want any more electrical units on my pump.
As I am monkeying around with different configurations, I often have dripping fittings, and occasional deluges due to priming, venting, etc.

Thanks,
John

2

Frequently Asked Questions / Re: Cycle Sensor Question; use of current as a flow rate proxy

« on: March 26, 2015, 12:39:00 AM »

I expect you are correct regarding current drain decrease with decrease of water height in the well. My vacuum gauge is over at the well, 100 yard dash to or from the pump and current probe. No way to assess correlation until I can re plumb the RJC to fit suction and discharge gauges. The ports are too close for my gauges to both fit. My pump house roof is 8 feet up, although putting the pump on the roof rather defeats the concept of protective housing...
Am travelling on a troubleshooting, no progress to report.
John

3

Frequently Asked Questions / Re: Cycle Sensor Question; use of current as a flow rate proxy

« on: March 24, 2015, 03:33:16 PM »

OK, very helpful.

I was running more tests today, and I managed to overpump the well...
The pump sure sounds different with air in the jet!

Good news, at that point the run current dropped to 7.31 A (and pressure dropped to zero), so I could certainly differentiate that from the run current which is 7.53 when I have flow and maybe 7.48 when i have very little flow.
So, at minimum,  the Cycle Sensor would release me from babysitting the pump whenever it is on.

I have one other idea, to raise up the jet pump off the ground by 8 feet, so that the pump output will stall before I can pull air and lose prime. (23 feet down to the top of the foot valve). The Red Lion literature had mentioned the use of a 30 foot 'drop pipe' below a suspended jet in a low yield well. Now I understand 'drop pipe'. Probably some leftover wisdom from the guys who knew stuff...

One other way to use the CycleSensor is essentially a motor temperature sensor, and thus a pseudo-runtime controller.  I live close enough to the ocean that we don't have big air temp excursions. As the motor warms up from cold, the current creeps down, roughly 5% over 15 minutes. The 10mA resolution of the CycleSensor should be plenty good, if it is relatively insensitive to ambient temperature. If necessary I can thermally isolate the CycleSensor from the heated air coming from the motor.
Thanks again,
John

4

Frequently Asked Questions / Re: Cycle Sensor Question; use of current as a flow rate proxy

« on: March 24, 2015, 01:27:01 PM »

What resolution of  threshold current does the Cycle Sensor offer?
Thanks,
John

5

Frequently Asked Questions / Re: Does a CSV valve have backflow? Updated after studying your site

« on: March 24, 2015, 01:20:19 PM »

thanks, I'll get the stuff and try it out, and let you know if I need more ideas.
John

6

Frequently Asked Questions / Re: Cycle Sensor Question; use of current as a flow rate proxy

« on: March 23, 2015, 08:02:44 PM »

Well, I wired up a pigtail so I could get my current probe around the black wire. (Amprobe DcG-1000)
RedLion RJC-100, jet control roughly two turns from closed.

Three observations;
 1. with the jet suction at -17.5 inHg and the pump output up at 60psi (very little flow), the pump was drawing maybe 7.48A . when I cracked open a bib on the output to get the pressure down to 55, higher flow, the pump drew 7.53 A.

2. At first, the 60psi current was maybe 7.73 amps. this seemed to decline uniformly over time, without regard to pumping. I assume this is the motor heating up and having higher ohmic resistance of the windings.

3. When I open up the bib to get the pressure down to 40, the  current does go up a lot.

After 1/2 day of testing, The jet pump current seems rather insensitive to the input suction pressure, when the flow is limited by the peak pressure. I may try again tomorrow with higher flow, but I'm leery of losing prime during these experiments.

I didn't have a very good way to modulate the depth in the well, but I am not optimistic at this point.
Maybe my technique was not flawless, but i didn't have a flow meter.
I have no idea about the effect of that discharge control, and Red Lion was coy at best about what it actually does.

Thanks for your ideas.
John

7

Frequently Asked Questions / Cycle Sensor Question; use of current as a flow rate proxy

« on: March 23, 2015, 12:09:17 PM »

I'm wondering about using the Cycle Sensor to run my jet pump (which is refilling a tank) from my low yield well.

Might it be possible to set a somewhat higher threshold than the 'dry run' condition which I abhor due to loss of prime? ( 300 feet of 2" suction, 25 foot well, etc.) My purported 'rationale' follows:
 
At first, the well has recharged and the suction is less negative, the flow rate is higher and thus the current might be higher, (with more water being raised from -5psi to +60)
 
As i draw down the well volume, the suction pressure goes to a more negative value,
 (let's say with the pump discharging through a ~PRV or CSV  into an open tank),
(more work for the pump to raise from -10psi to +60, but the venturi is becoming less efficient faster, and the throughput decreases faster than linearly)

Perhaps the current will  then go down below my elevated 'dry run' threshold, and the CS would shutdown for a delayed restart maybe 15 minutes later, to have less than 100 cycles/day.
If this worked, it would be an adaptive way to cycle the pump which would  not exceed the well yield ,
if I wait long enough between cycles so that the startup flow surge doesn't overpump immediately , in the first 10 seconds.


I'm sold on the Cycle Sensor, but just wondering what to expect from it before I order.
Also, does the Dry Pump detection require current continuously below threshold  10 seconds?
Does the threshold have 'hysteresis', where the current must  first exceed the threshold prior to detecting subthreshold current?

Before I go spend half a day testing, how reflective of  GPM throughput is the jet pump current? I imagine the inefficiency of the jet relative to a submersible would make this approach harder to do with a jet pump.

I'm paying $0.35 for my kwh, so, the intermittent operation seems attractive vs continuous  24 hr operation of a 1 HP jet throttled to 0.75 gpm.
Also, speaking of $0.35/kwh, what is the power supply current consumed by Cycle Sensor unit?
Thanks,
John

8

Frequently Asked Questions / Re: Does a CSV valve have backflow? Updated after studying your site

« on: March 23, 2015, 11:06:31 AM »

Cary,
thanks for the advice. I'm still wondering about the best way to keep the (jet support) pressure tank pressurized when the pump shuts off. I think it would just drain out into the big holding tank . I've been using a hose bib I crack open during pumping and close before I shut down manually. I guess a solenoid valve would work, but it seems kludgey. Can I just use a PRV for this?
John

9

Frequently Asked Questions / Re: Does a CSV valve have backflow? Updated after studying your site

« on: March 23, 2015, 03:19:57 AM »

I just read the post from Dovecreek, and suddenly realized that 'Dole'  flow regulation 'valves'  might be very good for me,
at least on avoiding overpumping. Those valves seem like a constant current diode, where the PRV seems more like a zener, or maybe a PNP with the zener from base to ground.

I'll still be looking for a way to maintain some minimum pressure in the jet pump after I shut it down, regardless of whatever else can happen. I'm increasingly of a mind to put another checkvalve at the jet pump input, even though it will foil my ability to prime the suction line through the priming port of the jet pump. I run the risk of sucking outside air into the loooong suction line, but I don't like cycling it from -10psi to ~ +40  either. The other good thing about the input check valve is I can install a 'float valve' to vent any air bubbles automatically, without it operating in reverse...

I guess I need a traditional PRV, somewhere in the 30-50 PSI range,   on the output manifold, with a Dole valve after that. The PRV is to not allow the tank fill to drain out the (jet support) pressure tank after the pump is stopped , while the Dole valve would prevent  the tank fill process from overpumping the well.j
,
Similarly, I think I might need a Dole valve between the pump and the (Jet Support) pressure tank, maybe with a reversed direction check valve in parallel, to allow rapid recharge of the jet  as needed for hiccups, while avoiding overpumping the well to fill the (Jet Support) pressure tank at startup.

This whole system is just to fill my storage tank, which is probably where a CSV would be useful to minimize pressure variation from cut-in to cut-out of the distribution pump.
Thanks for your patience with this challenging situation.
John

10

Frequently Asked Questions / Any ideas about how to fix a leaky redwood tank?

« on: March 23, 2015, 02:52:09 AM »

 One problem is the high leak rate when you are restarting an old dried out tank.

I had some luck with hanging a rainbird sprinkler inside to wet down the whole thing instead of just filling it from the bottom. I had some water in the creek after a big storm and got the tank full  that way,
but,
there are some leaks at the bottom that didn't get better with time.
(where the ones on the sides tended to seal themselves off.
It leaks out 10K gallons in a few days.

I get the impression that maybe at the lowest point in the tank, the rain has been washing through there and maybe washed the tannins out of the wood there?

I enjoyed your tubing-down-the-well sensor for water depth, and hoped you might have some ideas for the tank.

The tank bands are working, but the nuts are rusted in place, and I am not eager to try to get them moving.
I did put a couple of 2inch nylon straps around the tank and winch them down, as a way to reduce the initial leaks.
But when I got it full, the bands were all tight and apparently OK.
I'd really rather not take the bands off if there is any way to avoid it.

I seem to have one leak through the floor, and one at the joint between floor and staves at that low point.
I was hoping to put something in there that would be hygroscopic and swell up, but I couldn't find anywhere I could say was 'the leak'. Maybe I need to really dry it out, like tarp the thing and put a dehumidifier in there...

Thanks,
John

11

Frequently Asked Questions / Does a CSV valve have backflow? Updated after studying your site

« on: March 20, 2015, 06:17:57 PM »

Hello;
UPDATED: I spent more time reading and realized I want to ask different questions.
I deleted the old ones as they didn't make much sense in light of what I now understand you have....

 I was going to start by saying I have an unusual situation, but I  then read enough posts to realize the tremendous diversity of situations, and I won't claim to be unusual. I didn't see it covered elsewhere.

Anyway, I have a low-yield 25' well, at about 200 feet above sea level; i.e. usually 29.98 inHg barometric pressure.
It is about 300 feet away from my pump house, connected by a buried 2" Pvc pipe.
I have been using a 1HP Red Lion RJC-100 to pump it.
The 2inch PVC does *not* slope uniformly upwards to the pump, and thus it is a pain(!) to get primed.
There is a foot valve at the bottom of the suction line in the well.

The only way I can avoid overpumping the well (and sucking air, and losing prime) is to restrict the outflow to be up at 60psi. I have been trying to use a (old 1.5") pressure relief valve set at 60, but the setpoint is not very abrupt; i.e. not much difference between 60psi and 63 psi.
I'm still trying to get a good reading on the yield, but I think it is less than 1 GPM.

I also have a bubble trap I can vent , in piping above the jet pump output.
The other key to success is to have the pressure tank sitting at at least 50 PSI for startup;
this ensures the pump gets started without the dreaded 0PSI situation where there is no water in the jet.
Also, having the pressure tank helps make the jet pump more robust against entrained air;
when the pump gets an air bubble hiccup, the tank pressure pushes some water back into the jet pump and it burps and bounces around and then gets back to work. If i have gotten some air in the line, i  can carefully vent it without losing the jet venturi action.

(I haven't explored the lower bound of pressure tank PSI to ensure startup.
Admittedly, the pump stutters  badly initially until I vent some water and it settles down at ~75PSI, ramping down to 60 as the 2inch PVc transitions from +50psi to -10psi.
this is less than elegant... UPDATE; I realize I  need to just bypass the pressure switch on the RJC instead of trying to crank it up to 11ty...).
(At present, when I turn off the jet pump, the entire jet pump goes down to -10psi unless I allow it to suck water back in from the pressure tank).

Anyway, I'm trying to get this rig into a situation where it could operate unattended, and exploit the low-yield resource by filling up my 10K gallon redwood tank. (which presently leaks...)
I need a better PRV with a sharp cutoff, vs. gradual opening above the breakpoint.
It seems that you have this this behavior in the CSV, with the additional feature of the bypass flow.

My UPdated questions;
1. Where can I find data for flow vs. pressure when the CSV is shut, particularly in reverse pressure situations?
(somehow I am dubious that it is 1GPM regardless of differential pressure)
2. How do the smart people utilize the friction loss vs. flow rate data?
( i.e., CSV2  has ~7psi of friction loss at 0 GPM? I don't get that at all).
3. At this point I think I need a CSV (set at ~50Psi (or maybe PRV) to a pressure tank , which has a reverse check valve in parallel with the CSV to allow the suction line to recharge? and also on the pump output manifold, a PRV set to 60PSI which refills my big open tank. The idea of all of this is to insure the jet pump will restart, and then have it's output flowrate-limited to not overpump. (maybe I could add an input check valve, to minimize pressure cycling of my looooong  2inch PVC suction line. This goes against your generic advice of mutiple check valves in a single line.


Right now I have a 80 gal pressure tank, and I can overpump the well  (suck air, lose prime) just trying to get it filled up if it is empty and the well has not recovered any depth.

So, the remote shallow well that is only 25" deep is the source of many headaches.
I am hoping to find a way to keep my jet pump happy without needing an engineer to babysit it, and then use the ~1GPM to fill my big tank, which has it's own pump and hydrant network.

So, the  low yield shallow remote well  requires jet pump operating into a sharp PRV.
 The only way  I see to avoid overpumping is to sit up at the very high  pressure end of the pump curve, maybe 60pSI where zero flow pressure is 63 psi.
Thus, I am grasping at straws, to see if your fine CSV could help me out here.
(I don't seem to find any 1 GPM pumps that can pull from 25 feet down...)
 
So, whadayatink?
John
 I realize the 'reasonable' approach is to get power out to the well, and install one of your Cycle Sensors on a submersible.
Right now that is not feasible.